feat: spec + repo

.forgejo/workflows/default.yml

@@ -1,7 +1,6 @@
 name: default
 
 on:
-  workflow_dispatch:
   push:
     branches: [ "main", "develop" ]
     paths-ignore:

CHANGELOG.md

@@ -45,19 +45,6 @@ To have a consistent experience across all packages, some public interfaces have
 
 ### Changed
 
-- **request.result:** Document that `Result`/`Result<T>` equality treats any two failures as equal, ignoring error content; branch on the `Error` directly for failure-specific logic
-
-### Fixed
-
-- **request.result:** Correct the namespace in the `Prelude` doc comment (`Geekeey.Extensions.Result` → `Geekeey.Request.Result`)
-- **request.result:** Fold `IsSuccess` into `Result<T>.GetHashCode` to avoid collisions between a failure and a success value whose hash is `0`
-- **request.validation:** Guard null comparison bounds in `GreaterThan`/`LessThan`/`Between` etc. so a `null` bound no longer throws (`NullReferenceException`)
-- **request.validation:** Return no problems when validating a `null` instance of a reference type instead of dereferencing it (`NullReferenceException`)
-- **request.validation:** Make `Severity` meaningful — `Validation.IsValid` now only fails on `Error` problems; `Warning`/`Info` no longer invalidate. Added `Validation.IsValidFor(Severity)` to set the failing-severity threshold
-- **request.dispatcher:** Throw `InvalidOperationException` listing candidates when multiple handlers match a request instead of silently resolving via `.First()`. Also throws when no handler is registered
-- **request.dispatcher:** Resolve handlers/behaviors in registration order across closed and open generics instead of the fixed closed-before-open reflection order
-- **request.dispatcher:** Add `AddBehavior<T>(order:)` registration-time API so pipeline behavior ordering is explicit and deterministic (lower order runs first, registration order as tie-break) instead of relying on reflection/discovery order
-
 ### Removed
 
 [1.0.0]: https://code.geekeey.de/geekeey/request/releases/tag/1.0.0

Directory.Packages.props

@@ -12,5 +12,8 @@
     <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="4.14.0" />
     <PackageVersion Include="Microsoft.SourceLink.Gitea" Version="10.0.102" />
     <PackageVersion Include="TUnit" Version="1.11.51" />
+    <PackageVersion Include="Microsoft.EntityFrameworkCore" Version="10.0.6" />
+    <PackageVersion Include="Microsoft.EntityFrameworkCore.Relational" Version="10.0.6" />
+    <PackageVersion Include="Microsoft.EntityFrameworkCore.InMemory" Version="10.0.6" />
   </ItemGroup>
 </Project>

request.slnx

@@ -5,4 +5,8 @@
   <Project Path="src/request.validation.tests/Geekeey.Request.Validation.Tests.csproj" />
   <Project Path="src/request.result/Geekeey.Request.Result.csproj" />
   <Project Path="src/request.result.tests/Geekeey.Request.Result.Tests.csproj" />
+  <Project Path="src/request.persistence/Geekeey.Request.Persistence.csproj" />
+  <Project Path="src/request.persistence.tests/Geekeey.Request.Persistence.Tests.csproj" />
+  <Project Path="src/request.persistence.entityframeworkcore/Geekeey.Request.Persistence.EntityFrameworkCore.csproj" />
+  <Project Path="src/request.persistence.entityframeworkcore.tests/Geekeey.Request.Persistence.EntityFrameworkCore.Tests.csproj" />
 </Solution>

src/request.dispatcher.tests/ScalarBehaviourTests.cs

@@ -87,26 +87,6 @@ internal sealed class ScalarBehaviourTests
 		await Assert.That(tracker.Executed).IsTrue();
 	}
 
-	[Test]
-	public async Task I_can_order_behaviours_explicitly_by_order_property()
-	{
-		var sc = new ServiceCollection();
-		sc.AddSingleton<ScalarTestTracker>();
-		sc.AddRequestDispatcher(builder => builder
-			.Add(typeof(ScalarTestHandler))
-			.AddBehavior<OrderedScalarBehaviorA>(2)
-			.AddBehavior<OrderedScalarBehaviorB>(1));
-		var provider = sc.BuildServiceProvider();
-		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
-		var tracker = provider.GetRequiredService<ScalarTestTracker>();
-
-		var request = new ScalarTestRequest { Value = "Hello" };
-		await dispatcher.DispatchAsync(request);
-
-		// Registered A (order 2) then B (order 1) via AddBehavior; explicit order overrides discovery order.
-		await Assert.That(tracker.Log).IsEquivalentTo(["OrderedB", "OrderedA"]);
-	}
-
 	[Test]
 	public async Task I_can_maintain_the_ordering_between_open_and_closed_behaviours()
 	{

src/request.dispatcher.tests/ScalarDispatcherTests.cs

@@ -116,7 +116,7 @@ internal sealed class ScalarDispatcherTests
 	}
 
 	[Test]
-	public async Task I_can_see_it_throw_on_ambiguous_concrete_and_constrained_scalar_handlers()
+	public async Task I_can_dispatch_a_request_async_with_an_interface_constrained_handler()
 	{
 		var sc = new ServiceCollection();
 		sc.AddRequestDispatcher(builder => builder
@@ -126,18 +126,13 @@ internal sealed class ScalarDispatcherTests
 		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
 
 		var request = new InterfaceInheritedScalarRequest { Name = "Constrained" };
+		var result = await dispatcher.DispatchAsync(request);
 
 		// Both InterfaceInheritedScalarHandler and InterfaceConstrainedScalarHandler could match.
 		// InterfaceInheritedScalarHandler is a concrete match for InterfaceInheritedScalarRequest.
 		// InterfaceConstrainedScalarHandler is an open generic match.
-		// Ambiguity is no longer resolved silently with .First(); it throws instead.
-		var ex = await Assert.That(async () => await dispatcher.DispatchAsync(request)).Throws<InvalidOperationException>();
-
-		using (Assert.Multiple())
-		{
-			await Assert.That(ex?.Message).Contains(nameof(InterfaceInheritedScalarHandler));
-			await Assert.That(ex?.Message).Contains("InterfaceConstrainedScalarHandler");
-		}
+		// Currently Dispatcher.SendAsync checks concrete handlers first.
+		await Assert.That(result).IsEquivalentTo("Constrained-InterfaceHandled");
 	}
 
 	[Test]
@@ -239,49 +234,6 @@ internal sealed class ScalarDispatcherTests
 		}
 	}
 
-	[Test]
-	public async Task I_can_see_it_throw_on_ambiguous_scalar_handlers()
-	{
-		var sc = new ServiceCollection();
-		sc.AddRequestDispatcher(builder => builder
-			.Add(typeof(DuplicateScalarHandlerA))
-			.Add(typeof(DuplicateScalarHandlerB)));
-		var provider = sc.BuildServiceProvider();
-		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
-
-		var request = new DuplicateScalarRequest();
-		var ex = await Assert.That(async () => await dispatcher.DispatchAsync(request)).Throws<InvalidOperationException>();
-
-		using (Assert.Multiple())
-		{
-			await Assert.That(ex?.Message).Contains(nameof(DuplicateScalarHandlerA));
-			await Assert.That(ex?.Message).Contains(nameof(DuplicateScalarHandlerB));
-		}
-	}
-
-	[Test]
-	public async Task I_can_see_candidates_ordered_by_registration_not_closed_first()
-	{
-		var sc = new ServiceCollection();
-		sc.AddRequestDispatcher(builder => builder
-			.Add(typeof(InterfaceConstrainedScalarHandler<>))
-			.Add(typeof(InterfaceInheritedScalarHandler)));
-		var provider = sc.BuildServiceProvider();
-		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
-
-		var request = new InterfaceInheritedScalarRequest { Name = "Constrained" };
-
-		// The open generic handler is registered before the closed handler, so candidates must be
-		// listed in registration order (open first), not the old fixed closed-before-open order.
-		var ex = await Assert.That(async () => await dispatcher.DispatchAsync(request)).Throws<InvalidOperationException>();
-
-		var message = ex?.Message ?? string.Empty;
-		var openIndex = message.IndexOf("InterfaceConstrainedScalarHandler", StringComparison.Ordinal);
-		var closedIndex = message.IndexOf("InterfaceInheritedScalarHandler", StringComparison.Ordinal);
-
-		await Assert.That(openIndex >= 0 && closedIndex >= 0 && openIndex < closedIndex).IsTrue();
-	}
-
 	[Test]
 	public async Task I_can_see_it_throw_if_dispatcher_options_are_modified_after_build()
 	{

src/request.dispatcher.tests/StreamBehaviourTests.cs

@@ -66,26 +66,6 @@ internal sealed class StreamBehaviourTests
 		await Assert.That(tracker.Log[1]).IsEquivalentTo("Behaviour2");
 	}
 
-	[Test]
-	public async Task I_can_order_behaviours_explicitly_by_order_property()
-	{
-		var sc = new ServiceCollection();
-		sc.AddSingleton<StreamTestTracker>();
-		sc.AddRequestDispatcher(builder => builder
-			.Add(typeof(StreamTestHandler))
-			.AddBehavior<OrderedStreamBehaviorA>(2)
-			.AddBehavior<OrderedStreamBehaviorB>(1));
-		var provider = sc.BuildServiceProvider();
-		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
-		var tracker = provider.GetRequiredService<StreamTestTracker>();
-
-		var request = new StreamTestRequest { Value = "Hello" };
-		await dispatcher.DispatchAsync(request).ToListAsync();
-
-		// Registered A (order 2) then B (order 1) via AddBehavior; explicit order overrides discovery order.
-		await Assert.That(tracker.Log).IsEquivalentTo(["OrderedB", "OrderedA"]);
-	}
-
 	[Test]
 	public async Task I_can_work_with_a_generic_wrapper_request_and_the_open_behaviour()
 	{

src/request.dispatcher.tests/StreamDispatcherTests.cs

@@ -7,26 +7,6 @@ namespace Geekeey.Request.Dispatcher.Tests;
 
 public class StreamDispatcherTests
 {
-	[Test]
-	public async Task I_can_see_it_throw_on_ambiguous_stream_handlers()
-	{
-		var sc = new ServiceCollection();
-		sc.AddRequestDispatcher(builder => builder
-			.Add(typeof(DuplicateStreamHandlerA))
-			.Add(typeof(DuplicateStreamHandlerB)));
-		var provider = sc.BuildServiceProvider();
-		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
-
-		var request = new DuplicateStreamRequest();
-		var ex = await Assert.That(async () => await dispatcher.DispatchAsync(request).ToListAsync()).Throws<InvalidOperationException>();
-
-		using (Assert.Multiple())
-		{
-			await Assert.That(ex?.Message).Contains(nameof(DuplicateStreamHandlerA));
-			await Assert.That(ex?.Message).Contains(nameof(DuplicateStreamHandlerB));
-		}
-	}
-
 	[Test]
 	public async Task I_can_dispatch_a_request_async_with_an_open_generic_handler()
 	{
@@ -141,18 +121,13 @@ public class StreamDispatcherTests
 		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
 
 		var request = new InterfaceInheritedStreamRequest { Name = "Constrained" };
+		var results = await dispatcher.DispatchAsync(request).ToListAsync();
 
 		// Both InterfaceInheritedStreamHandler and InterfaceConstrainedStreamHandler could match.
 		// InterfaceInheritedStreamHandler is a concrete match for InterfaceInheritedStreamRequest.
 		// InterfaceConstrainedStreamHandler is an open generic match.
-		// Ambiguity is no longer resolved silently with .First(); it throws instead.
-		var ex = await Assert.That(async () => await dispatcher.DispatchAsync(request).ToListAsync()).Throws<InvalidOperationException>();
-
-		using (Assert.Multiple())
-		{
-			await Assert.That(ex?.Message).Contains(nameof(InterfaceInheritedStreamHandler));
-			await Assert.That(ex?.Message).Contains("InterfaceConstrainedStreamHandler");
-		}
+		// Currently Dispatcher checks concrete handlers first.
+		await Assert.That(results).IsEquivalentTo(["Constrained-InterfaceHandled-0", "Constrained-InterfaceHandled-1"]);
 	}
 
 	[Test]

src/request.dispatcher.tests/_fixtures/DuplicateScalarHandler.cs

@@ -1,24 +0,0 @@
-// Copyright (c) The Geekeey Authors
-// SPDX-License-Identifier: EUPL-1.2
-
-namespace Geekeey.Request.Dispatcher.Tests;
-
-public sealed class DuplicateScalarRequest : IScalarRequest<string>
-{
-}
-
-public sealed class DuplicateScalarHandlerA : IScalarRequestHandler<DuplicateScalarRequest, string>
-{
-	public Task<string> HandleAsync(DuplicateScalarRequest request, CancellationToken cancellationToken)
-	{
-		return Task.FromResult("A");
-	}
-}
-
-public sealed class DuplicateScalarHandlerB : IScalarRequestHandler<DuplicateScalarRequest, string>
-{
-	public Task<string> HandleAsync(DuplicateScalarRequest request, CancellationToken cancellationToken)
-	{
-		return Task.FromResult("B");
-	}
-}

src/request.dispatcher.tests/_fixtures/DuplicateStreamHandler.cs

@@ -1,24 +0,0 @@
-// Copyright (c) The Geekeey Authors
-// SPDX-License-Identifier: EUPL-1.2
-
-namespace Geekeey.Request.Dispatcher.Tests;
-
-public sealed class DuplicateStreamRequest : IStreamRequest<string>
-{
-}
-
-public sealed class DuplicateStreamHandlerA : IStreamRequestHandler<DuplicateStreamRequest, string>
-{
-	public async IAsyncEnumerable<string> HandleAsync(DuplicateStreamRequest request, [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken)
-	{
-		yield return "A";
-	}
-}
-
-public sealed class DuplicateStreamHandlerB : IStreamRequestHandler<DuplicateStreamRequest, string>
-{
-	public async IAsyncEnumerable<string> HandleAsync(DuplicateStreamRequest request, [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken)
-	{
-		yield return "B";
-	}
-}

src/request.dispatcher.tests/_fixtures/OrderedScalarBehavior.cs

@@ -1,22 +0,0 @@
-// Copyright (c) The Geekeey Authors
-// SPDX-License-Identifier: EUPL-1.2
-
-namespace Geekeey.Request.Dispatcher.Tests;
-
-public class OrderedScalarBehaviorA(ScalarTestTracker tracker) : IScalarRequestBehavior<ScalarTestRequest, string>
-{
-	public async Task<string> HandleAsync(ScalarTestRequest request, ScalarHandlerDelegate<string> next, CancellationToken cancellationToken)
-	{
-		tracker.Log.Add("OrderedA");
-		return await next(request, cancellationToken);
-	}
-}
-
-public class OrderedScalarBehaviorB(ScalarTestTracker tracker) : IScalarRequestBehavior<ScalarTestRequest, string>
-{
-	public async Task<string> HandleAsync(ScalarTestRequest request, ScalarHandlerDelegate<string> next, CancellationToken cancellationToken)
-	{
-		tracker.Log.Add("OrderedB");
-		return await next(request, cancellationToken);
-	}
-}

src/request.dispatcher.tests/_fixtures/OrderedStreamBehavior.cs

@@ -1,28 +0,0 @@
-// Copyright (c) The Geekeey Authors
-// SPDX-License-Identifier: EUPL-1.2
-
-namespace Geekeey.Request.Dispatcher.Tests;
-
-public class OrderedStreamBehaviorA(StreamTestTracker tracker) : IStreamRequestBehavior<StreamTestRequest, string>
-{
-	public async IAsyncEnumerable<string> HandleAsync(StreamTestRequest request, StreamHandlerDelegate<string> next, [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken)
-	{
-		tracker.Log.Add("OrderedA");
-		await foreach (var item in next(request, cancellationToken))
-		{
-			yield return item;
-		}
-	}
-}
-
-public class OrderedStreamBehaviorB(StreamTestTracker tracker) : IStreamRequestBehavior<StreamTestRequest, string>
-{
-	public async IAsyncEnumerable<string> HandleAsync(StreamTestRequest request, StreamHandlerDelegate<string> next, [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken)
-	{
-		tracker.Log.Add("OrderedB");
-		await foreach (var item in next(request, cancellationToken))
-		{
-			yield return item;
-		}
-	}
-}

src/request.dispatcher/RequestDispatcherBuilderExtensions.cs

@@ -70,27 +70,6 @@ public static class RequestDispatcherBuilderExtensions
 		return builder;
 	}
 
-	/// <summary>
-	/// Adds the specified pipeline behavior to the request dispatcher configuration, with an explicit
-	/// pipeline <paramref name="order"/> used to determine its position in the pipeline. Lower values run
-	/// first (outermost); behaviors with equal order run in registration order.
-	/// </summary>
-	/// <typeparam name="TBehavior">The behavior type to add. Must implement a request behavior interface.</typeparam>
-	/// <param name="builder">The <see cref="IRequestDispatcherBuilder"/> to configure.</param>
-	/// <param name="order">The pipeline order for this behavior. Defaults to <c>0</c>.</param>
-	/// <returns>The <see cref="IRequestDispatcherBuilder"/> instance for further configuration.</returns>
-	public static IRequestDispatcherBuilder AddBehavior<TBehavior>(this IRequestDispatcherBuilder builder, int order = 0)
-		where TBehavior : class
-	{
-		ArgumentNullException.ThrowIfNull(builder);
-		ValidateNoNestedRequestHandlers([typeof(TBehavior)]);
-
-		builder.Services.AddOptions<RequestDispatcherOptions>()
-			.Configure(options => options.Inspect([typeof(TBehavior)], order));
-
-		return builder;
-	}
-
 	/// <summary>
 	/// Adds the specified type to the request dispatcher configuration for inspection.
 	/// </summary>

src/request.dispatcher/RequestDispatcherOptions.cs

@@ -10,27 +10,24 @@ namespace Geekeey.Request.Dispatcher;
 
 internal sealed class RequestDispatcherOptions
 {
-	private readonly List<(Type Type, int? Order)> _search = [];
+	private readonly List<Type> _search = [];
 	private readonly Lazy<TypeIndex> _behaviorsTypeIndex;
 	private readonly Lazy<TypeIndex> _handlersTypeIndex;
 
 	public RequestDispatcherOptions()
 	{
-		_behaviorsTypeIndex = new Lazy<TypeIndex>(() => new BehaviorTypeIndex(_search.DistinctBy(x => x.Type)));
-		_handlersTypeIndex = new Lazy<TypeIndex>(() => new HandlerTypeIndex(_search.DistinctBy(x => x.Type)));
+		_behaviorsTypeIndex = new Lazy<TypeIndex>(() => new BehaviorTypeIndex(_search.Distinct()));
+		_handlersTypeIndex = new Lazy<TypeIndex>(() => new HandlerTypeIndex(_search.Distinct()));
 	}
 
-	public void Inspect(IEnumerable<Type> assembly, int? order = null)
+	public void Inspect(IEnumerable<Type> assembly)
 	{
 		if (_behaviorsTypeIndex.IsValueCreated || _handlersTypeIndex.IsValueCreated)
 		{
 			throw new InvalidOperationException("The type index has already been created. Cannot inspect new assemblies.");
 		}
 
-		foreach (var type in assembly)
-		{
-			_search.Add((type, order));
-		}
+		_search.AddRange(assembly);
 	}
 
 	public IEnumerable<T> GetRequestBehaviors<T>(IServiceProvider services)
@@ -49,22 +46,11 @@ internal sealed class RequestDispatcherOptions
 
 		protected readonly Dictionary<Type, List<Type>> _closedTypeInfo = [];
 		protected readonly List<Type> _openTypeInfo = [];
-		protected readonly Dictionary<Type, int> _order = [];
-		protected readonly Dictionary<Type, int> _explicitOrder = [];
 
-		protected TypeIndex(IEnumerable<(Type Type, int? Order)> collection, Func<Type, bool> predicate)
+		protected TypeIndex(IEnumerable<Type> collection, Func<Type, bool> predicate)
 		{
-			var index = 0;
-
-			foreach (var (type, order) in collection)
+			foreach (var type in collection)
 			{
-				_order[type] = index++;
-
-				if (order is { } explicitOrder)
-				{
-					_explicitOrder[type] = explicitOrder;
-				}
-
 				if (type.IsGenericTypeDefinition)
 				{
 					if (type.GetInterfaces().Any(predicate))
@@ -82,11 +68,6 @@ internal sealed class RequestDispatcherOptions
 			}
 		}
 
-		protected int EffectiveOrder(Type type)
-		{
-			return _explicitOrder.TryGetValue(type, out var order) ? order : _order[type];
-		}
-
 		public IEnumerable<T> Resolve<T>(IServiceProvider services)
 		{
 			return (IEnumerable<T>)_cache.GetOrAdd(typeof(T), CreateResolverFactory<T>)(services);
@@ -116,19 +97,16 @@ internal sealed class RequestDispatcherOptions
 				type.GetGenericTypeDefinition() == typeof(IStreamRequestHandler<,>));
 	}
 
-	private sealed class HandlerTypeIndex(IEnumerable<(Type Type, int? Order)> collection)
+	private sealed class HandlerTypeIndex(IEnumerable<Type> collection)
 		: TypeIndex(collection, IsRequestHandlerType)
 	{
 		protected override IReadOnlyList<Type> IsAssignableTo(Type @interface)
 		{
-			var result = new List<(int Order, Type Type)>();
+			var result = new List<Type>();
 
 			if (_closedTypeInfo.TryGetValue(@interface, out var list))
 			{
-				foreach (var type in list)
-				{
-					result.Add((EffectiveOrder(type), type));
-				}
+				result.AddRange(list);
 			}
 
 			var requestType = @interface.GetGenericArguments()[0];
@@ -143,7 +121,7 @@ internal sealed class RequestDispatcherOptions
 					var impl = type.MakeGenericType(requestType);
 					if (impl.IsAssignableTo(@interface))
 					{
-						result.Add((EffectiveOrder(type), impl));
+						result.Add(impl);
 					}
 				}
 				catch (ArgumentException)
@@ -159,7 +137,7 @@ internal sealed class RequestDispatcherOptions
 						var impl = type.MakeGenericType(requestType.GetGenericArguments());
 						if (impl.IsAssignableTo(@interface))
 						{
-							result.Add((EffectiveOrder(type), impl));
+							result.Add(impl);
 						}
 					}
 				}
@@ -168,7 +146,7 @@ internal sealed class RequestDispatcherOptions
 				}
 			}
 
-			return [.. result.OrderBy(static item => item.Order).Select(static item => item.Type)];
+			return result;
 		}
 	}
 
@@ -179,19 +157,16 @@ internal sealed class RequestDispatcherOptions
 				type.GetGenericTypeDefinition() == typeof(IStreamRequestBehavior<,>));
 	}
 
-	private sealed class BehaviorTypeIndex(IEnumerable<(Type Type, int? Order)> collection)
+	private sealed class BehaviorTypeIndex(IEnumerable<Type> collection)
 		: TypeIndex(collection, IsRequestBehaviorType)
 	{
 		protected override IReadOnlyList<Type> IsAssignableTo(Type @interface)
 		{
-			var result = new List<(int Order, Type Type)>();
+			var result = new List<Type>();
 
 			if (_closedTypeInfo.TryGetValue(@interface, out var list))
 			{
-				foreach (var type in list)
-				{
-					result.Add((EffectiveOrder(type), type));
-				}
+				result.AddRange(list);
 			}
 
 			var requestType = @interface.GetGenericArguments()[0];
@@ -205,7 +180,7 @@ internal sealed class RequestDispatcherOptions
 					var impl = behaviour.MakeGenericType(requestType, responseType);
 					if (impl.IsAssignableTo(@interface))
 					{
-						result.Add((EffectiveOrder(behaviour), impl));
+						result.Add(impl);
 					}
 				}
 				catch (ArgumentException)
@@ -218,7 +193,7 @@ internal sealed class RequestDispatcherOptions
 					var impl = behaviour.MakeGenericType(requestType.GetGenericArguments());
 					if (impl.IsAssignableTo(@interface))
 					{
-						result.Add((EffectiveOrder(behaviour), impl));
+						result.Add(impl);
 					}
 				}
 				catch (ArgumentException)
@@ -226,7 +201,7 @@ internal sealed class RequestDispatcherOptions
 				}
 			}
 
-			return [.. result.OrderBy(static item => item.Order).Select(static item => item.Type)];
+			return result;
 		}
 	}
 }

src/request.dispatcher/ScalarRequestInvoker.cs

@@ -43,20 +43,7 @@ internal sealed class ScalarRequestInvoker<TRequest, TResponse> : ScalarRequestI
 
 		Task<TResponse> Head(IScalarRequest<TResponse> r, CancellationToken ct)
 		{
-			var handlers = options.GetRequestHandlers<IScalarRequestHandler<TRequest, TResponse>>(serviceProvider).ToArray();
-
-			if (handlers.Length is 0)
-			{
-				throw new InvalidOperationException($"No handler is registered for request '{typeof(TRequest).FullName}'.");
-			}
-
-			if (handlers.Length > 1)
-			{
-				var candidates = string.Join(", ", handlers.Select(handler => handler.GetType().FullName));
-				throw new InvalidOperationException($"Multiple handlers are registered for request '{typeof(TRequest).FullName}'. Ambiguous handlers: {candidates}");
-			}
-
-			return handlers[0].HandleAsync((TRequest)r, ct);
+			return options.GetRequestHandlers<IScalarRequestHandler<TRequest, TResponse>>(serviceProvider).First().HandleAsync((TRequest)r, ct);
 		}
 	}
 }

src/request.dispatcher/StreamRequestInvoker.cs

@@ -47,20 +47,7 @@ internal sealed class StreamRequestInvoker<TRequest, TResponse> : StreamRequestI
 
 		IAsyncEnumerable<TResponse> Head(IStreamRequest<TResponse> r, CancellationToken ct)
 		{
-			var handlers = options.GetRequestHandlers<IStreamRequestHandler<TRequest, TResponse>>(serviceProvider).ToArray();
-
-			if (handlers.Length is 0)
-			{
-				throw new InvalidOperationException($"No handler is registered for request '{typeof(TRequest).FullName}'.");
-			}
-
-			if (handlers.Length > 1)
-			{
-				var candidates = string.Join(", ", handlers.Select(handler => handler.GetType().FullName));
-				throw new InvalidOperationException($"Multiple handlers are registered for request '{typeof(TRequest).FullName}'. Ambiguous handlers: {candidates}");
-			}
-
-			return handlers[0].HandleAsync((TRequest)r, ct);
+			return options.GetRequestHandlers<IStreamRequestHandler<TRequest, TResponse>>(serviceProvider).First().HandleAsync((TRequest)r, ct);
 		}
 	}
 }

src/request.persistence.entityframeworkcore.tests/.editorconfig

@@ -0,0 +1,8 @@
+
+[*.{cs,vb}]
+dotnet_diagnostic.CA1822.severity = none
+dotnet_diagnostic.CA1707.severity = none
+dotnet_diagnostic.IDE0060.severity = none
+dotnet_diagnostic.IDE0005.severity = none
+dotnet_diagnostic.IDE0390.severity = none
+dotnet_diagnostic.IDE0391.severity = none

src/request.persistence.entityframeworkcore.tests/EvaluationTests.cs

@@ -0,0 +1,507 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using Microsoft.EntityFrameworkCore;
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class EvaluationTests
+{
+	private static async Task<FakeDbContext> CreateDbContext()
+	{
+		var options = new DbContextOptionsBuilder<FakeDbContext>()
+			.UseInMemoryDatabase($"TestDb_{Guid.NewGuid()}")
+			.EnableServiceProviderCaching(false)
+			.Options;
+
+		var context = new FakeDbContext(options);
+		await context.Database.EnsureCreatedAsync();
+		return context;
+	}
+
+	private static async Task<Repository<FakeEntity>> CreateRepo()
+	{
+		var context = await CreateDbContext();
+		return new Repository<FakeEntity>(context);
+	}
+
+	private static async Task SeedData(Repository<FakeEntity> repo, params FakeEntity[] entities)
+	{
+		foreach (var entity in entities)
+		{
+			await repo.AddAsync(entity);
+		}
+	}
+
+	[Test]
+	public async Task Where_filters_entities_by_equality()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" },
+			new FakeEntity { Name = "Gamma" });
+
+		var result = await repo.ListAsync(new NameEqualSpec("Beta"));
+
+		await Assert.That(result).Count().IsEqualTo(1);
+		await Assert.That(result[0].Name).IsEqualTo("Beta");
+	}
+
+	[Test]
+	public async Task Where_multiple_filters_combine_as_and()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "AlphaBeta" },
+			new FakeEntity { Name = "Beta" });
+
+		var result = await repo.ListAsync(new MultipleWhereSpec());
+
+		await Assert.That(result).Count().IsEqualTo(1);
+		await Assert.That(result[0].Name).IsEqualTo("AlphaBeta");
+	}
+
+	[Test]
+	public async Task Where_no_match_returns_empty_list()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		var result = await repo.ListAsync(new NameEqualSpec("NonExistent"));
+
+		await Assert.That(result).IsEmpty();
+	}
+
+	[Test]
+	public async Task Where_with_FirstOrDefaultAsync_returns_matching()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		var result = await repo.FirstOrDefaultAsync(new NameEqualSpec("Alpha"));
+
+		await Assert.That(result).IsNotNull();
+		await Assert.That(result!.Name).IsEqualTo("Alpha");
+	}
+
+	[Test]
+	public async Task Where_with_FirstOrDefaultAsync_no_match_returns_null()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		var result = await repo.FirstOrDefaultAsync(new NameEqualSpec("NonExistent"));
+
+		await Assert.That(result).IsNull();
+	}
+
+	[Test]
+	public async Task Where_with_CountAsync_returns_correct_count()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" });
+
+		var count = await repo.CountAsync(new NameEqualSpec("Alpha"));
+
+		await Assert.That(count).IsEqualTo(2);
+	}
+
+	[Test]
+	public async Task Where_with_AnyAsync_returns_true_when_match_exists()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		var any = await repo.AnyAsync(new NameEqualSpec("Alpha"));
+
+		await Assert.That(any).IsTrue();
+	}
+
+	[Test]
+	public async Task Where_with_AnyAsync_returns_false_when_no_match()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		var any = await repo.AnyAsync(new NameEqualSpec("Beta"));
+
+		await Assert.That(any).IsFalse();
+	}
+
+	[Test]
+	public async Task Search_filters_by_like_pattern()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Albatross" },
+			new FakeEntity { Name = "Beta" });
+
+		var result = await repo.ListAsync(new SearchSpec("Al%"));
+
+		await Assert.That(result).Count().IsEqualTo(2);
+	}
+
+	[Test]
+	public async Task Search_exact_match_works_without_wildcard()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Albatross" });
+
+		var result = await repo.ListAsync(new SearchSpec("Alpha"));
+
+		await Assert.That(result).Count().IsEqualTo(1);
+		await Assert.That(result[0].Name).IsEqualTo("Alpha");
+	}
+
+	[Test]
+	public async Task Search_multiple_terms_in_same_group_combine_as_or()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" },
+			new FakeEntity { Name = "Gamma" });
+
+		var result = await repo.ListAsync(new MultiSearchSpec("Alpha", "Beta"));
+
+		await Assert.That(result).Count().IsEqualTo(2);
+	}
+
+	[Test]
+	public async Task OrderBy_returns_ascending()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Charlie" },
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" });
+
+		var result = await repo.ListAsync(new OrderByNameSpec());
+
+		await Assert.That(result).Count().IsEqualTo(3);
+		await Assert.That(result[0].Name).IsEqualTo("Alpha");
+		await Assert.That(result[1].Name).IsEqualTo("Beta");
+		await Assert.That(result[2].Name).IsEqualTo("Charlie");
+	}
+
+	[Test]
+	public async Task OrderByDescending_returns_descending()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Charlie" },
+			new FakeEntity { Name = "Beta" });
+
+		var result = await repo.ListAsync(new OrderByNameDescSpec());
+
+		await Assert.That(result).Count().IsEqualTo(3);
+		await Assert.That(result[0].Name).IsEqualTo("Charlie");
+		await Assert.That(result[1].Name).IsEqualTo("Beta");
+		await Assert.That(result[2].Name).IsEqualTo("Alpha");
+	}
+
+	[Test]
+	public async Task ThenBy_chains_after_order_by()
+	{
+		var repo = await CreateRepo();
+		var id1 = Guid.Parse("00000000-0000-0000-0000-000000000001");
+		var id2 = Guid.Parse("00000000-0000-0000-0000-000000000002");
+		var id3 = Guid.Parse("00000000-0000-0000-0000-000000000003");
+
+		await SeedData(repo,
+			new FakeEntity { Id = id2, Name = "Alpha" },
+			new FakeEntity { Id = id1, Name = "Alpha" },
+			new FakeEntity { Id = id3, Name = "Beta" });
+
+		var result = await repo.ListAsync(new OrderByNameThenByIdSpec());
+
+		await Assert.That(result).Count().IsEqualTo(3);
+		await Assert.That(result[0].Id).IsEqualTo(id1);
+		await Assert.That(result[1].Id).IsEqualTo(id2);
+		await Assert.That(result[2].Name).IsEqualTo("Beta");
+	}
+
+	[Test]
+	public async Task ThenByDescending_chains_after_order_by()
+	{
+		var repo = await CreateRepo();
+		var id1 = Guid.Parse("00000000-0000-0000-0000-000000000001");
+		var id2 = Guid.Parse("00000000-0000-0000-0000-000000000002");
+		var id3 = Guid.Parse("00000000-0000-0000-0000-000000000003");
+
+		await SeedData(repo,
+			new FakeEntity { Id = id2, Name = "Alpha" },
+			new FakeEntity { Id = id1, Name = "Alpha" },
+			new FakeEntity { Id = id3, Name = "Beta" });
+
+		var result = await repo.ListAsync(new OrderByNameThenByIdDescSpec());
+
+		await Assert.That(result).Count().IsEqualTo(3);
+		await Assert.That(result[0].Id).IsEqualTo(id2);
+		await Assert.That(result[1].Id).IsEqualTo(id1);
+		await Assert.That(result[2].Name).IsEqualTo("Beta");
+	}
+
+	[Test]
+	public async Task Duplicate_order_chain_throws()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		await Assert.That(async () => await repo.ListAsync(new DuplicateOrderSpec()))
+			.Throws<DuplicateOrderChainException>();
+	}
+
+	[Test]
+	public async Task Take_limits_results()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" },
+			new FakeEntity { Name = "Gamma" });
+
+		var result = await repo.ListAsync(new OrderedTakeSpec(2));
+
+		await Assert.That(result).Count().IsEqualTo(2);
+		await Assert.That(result[0].Name).IsEqualTo("Alpha");
+		await Assert.That(result[1].Name).IsEqualTo("Beta");
+	}
+
+	[Test]
+	public async Task Skip_skips_elements()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" },
+			new FakeEntity { Name = "Gamma" });
+
+		var result = await repo.ListAsync(new OrderedSkipSpec(1));
+
+		await Assert.That(result).Count().IsEqualTo(2);
+		await Assert.That(result[0].Name).IsEqualTo("Beta");
+	}
+
+	[Test]
+	public async Task Skip_and_take_paginates_correctly()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" },
+			new FakeEntity { Name = "Charlie" },
+			new FakeEntity { Name = "Delta" });
+
+		var result = await repo.ListAsync(new OrderedSkipTakeSpec(1, 2));
+
+		await Assert.That(result).Count().IsEqualTo(2);
+		await Assert.That(result[0].Name).IsEqualTo("Beta");
+		await Assert.That(result[1].Name).IsEqualTo("Charlie");
+	}
+
+	[Test]
+	public async Task Skip_zero_returns_all()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" });
+
+		var result = await repo.ListAsync(new SkipOnlySpec(0));
+
+		await Assert.That(result).Count().IsEqualTo(2);
+	}
+
+	[Test]
+	public async Task Pagination_is_ignored_by_CountAsync()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" },
+			new FakeEntity { Name = "Gamma" });
+
+		var count = await repo.CountAsync(new OrderedSkipTakeSpec(1, 1));
+
+		await Assert.That(count).IsEqualTo(3);
+	}
+
+	[Test]
+	public async Task Pagination_is_ignored_by_AnyAsync()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		var any = await repo.AnyAsync(new OrderedSkipSpec(10));
+
+		await Assert.That(any).IsTrue();
+	}
+
+	[Test]
+	public async Task Select_projects_entity_to_new_type()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" });
+
+		var result = await repo.ListAsync(new NameProjectionSpec());
+
+		await Assert.That(result).Count().IsEqualTo(2);
+		await Assert.That(result[0]).IsEqualTo("Alpha");
+		await Assert.That(result[1]).IsEqualTo("Beta");
+	}
+
+	[Test]
+	public async Task Select_with_FirstOrDefaultAsync_returns_projected_result()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		var result = await repo.FirstOrDefaultAsync(new NameProjectionSpec());
+
+		await Assert.That(result).IsEqualTo("Alpha");
+	}
+
+	[Test]
+	public async Task No_selector_on_projected_spec_throws()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		await Assert.That(async () => await repo.ListAsync(new NoSelectorSpec()))
+			.Throws<SelectorNotFoundException>();
+	}
+
+	[Test]
+	public async Task Concurrent_selectors_throws()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		await Assert.That(async () => await repo.ListAsync(new ConcurrentSelectorSpec()))
+			.Throws<ConcurrentSelectorsException>();
+	}
+
+	[Test]
+	public async Task Where_orderby_and_take_combine_correctly()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Charlie" },
+			new FakeEntity { Name = "Alice" },
+			new FakeEntity { Name = "Bob" },
+			new FakeEntity { Name = "David" });
+
+		var result = await repo.ListAsync(new CombinedWhereOrderTakeSpec());
+
+		await Assert.That(result).Count().IsEqualTo(2);
+		await Assert.That(result[0].Name).IsEqualTo("Alice");
+		await Assert.That(result[1].Name).IsEqualTo("Bob");
+	}
+
+	[Test]
+	public async Task PostProcessing_applies_after_query()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "AlphaBeta" },
+			new FakeEntity { Name = "Beta" });
+
+		var result = await repo.ListAsync(new PostProcessingSpec());
+
+		await Assert.That(result).Count().IsEqualTo(1);
+		await Assert.That(result[0].Name).IsEqualTo("Alpha");
+	}
+
+	[Test]
+	public async Task Where_only_returns_filtered()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" });
+
+		var result = await repo.ListAsync(new WhereSpec());
+
+		await Assert.That(result).Count().IsEqualTo(1);
+		await Assert.That(result[0].Name).IsEqualTo("Alpha");
+	}
+
+	[Test]
+	public async Task FirstOrDefaultAsync_returns_first_matching()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" });
+
+		var result = await repo.FirstOrDefaultAsync(new FirstOrderedSpec());
+
+		await Assert.That(result).IsNotNull();
+		await Assert.That(result!.Name).IsEqualTo("Alpha");
+	}
+
+	[Test]
+	public async Task CountAsync_without_spec_returns_all()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" });
+
+		var count = await repo.CountAsync();
+
+		await Assert.That(count).IsEqualTo(2);
+	}
+
+	[Test]
+	public async Task AnyAsync_without_spec_returns_true_when_entities_exist()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo, new FakeEntity { Name = "Alpha" });
+
+		var any = await repo.AnyAsync();
+
+		await Assert.That(any).IsTrue();
+	}
+
+	[Test]
+	public async Task AnyAsync_without_spec_returns_false_when_empty()
+	{
+		var repo = await CreateRepo();
+
+		var any = await repo.AnyAsync();
+
+		await Assert.That(any).IsFalse();
+	}
+
+	[Test]
+	public async Task AsAsyncEnumerable_streams_entities()
+	{
+		var repo = await CreateRepo();
+		await SeedData(repo,
+			new FakeEntity { Name = "Alpha" },
+			new FakeEntity { Name = "Beta" });
+
+		var count = 0;
+
+		await foreach (var _ in repo.AsAsyncEnumerable(new OrderByNameSpec()))
+		{
+			count++;
+		}
+
+		await Assert.That(count).IsEqualTo(2);
+	}
+}

src/request.persistence.entityframeworkcore.tests/Geekeey.Request.Persistence.EntityFrameworkCore.Tests.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="TUnit" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <AssemblyAttribute Include="System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverageAttribute" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\request.persistence.entityframeworkcore\Geekeey.Request.Persistence.EntityFrameworkCore.csproj" />
+  </ItemGroup>
+
+</Project>

src/request.persistence.entityframeworkcore.tests/IncludeEvaluatorTests.cs

@@ -0,0 +1,403 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+using Microsoft.EntityFrameworkCore;
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class IncludeEvaluatorTests
+{
+	private static async Task<FakeDbContext> CreateDbContext()
+	{
+		var context = new FakeDbContext(new DbContextOptionsBuilder<FakeDbContext>()
+			.UseInMemoryDatabase($"TestDb_{Guid.NewGuid()}")
+			.EnableServiceProviderCaching(false)
+			.Options);
+		await context.Database.EnsureCreatedAsync();
+		return context;
+	}
+
+	// --- Default evaluator (non-cached, reflection-based) ---
+
+	[Test]
+	public async Task Default_include_reference_nav()
+	{
+		var repo = await CreateRepo();
+		var entity = new FakeEntity
+		{
+			Name = "Test",
+			Child = new FakeChildEntity
+			{
+				Value = "child",
+			},
+		};
+		await repo.AddAsync(entity);
+
+		var result = await repo.ListAsync(new IncludeChildSpec());
+
+		await Assert.That(result).Count().IsEqualTo(1);
+		await Assert.That(result[0].Name).IsEqualTo("Test");
+	}
+
+	[Test]
+	public async Task Default_include_collection_nav()
+	{
+		var repo = await CreateRepo();
+		var entity = new FakeEntity
+		{
+			Name = "Test",
+		};
+		entity.Details.Add(new FakeDetailEntity
+		{
+			Value = "detail",
+		});
+		await repo.AddAsync(entity);
+
+		var result = await repo.ListAsync(new IncludeDetailsSpec());
+
+		await Assert.That(result).Count().IsEqualTo(1);
+		await Assert.That(result[0].Name).IsEqualTo("Test");
+	}
+
+	[Test]
+	public async Task Default_then_include_after_reference()
+	{
+		var repo = await CreateRepo();
+		var entity = new FakeEntity
+		{
+			Name = "Test",
+			Child = new FakeChildEntity
+			{
+				Value = "child",
+				GrandChildren =
+				{
+					new FakeGrandChildEntity
+					{
+						Value = "grand",
+					},
+				},
+			},
+		};
+		await repo.AddAsync(entity);
+
+		var result = await repo.ListAsync(new IncludeChildThenGrandChildrenSpec());
+
+		await Assert.That(result).Count().IsEqualTo(1);
+	}
+
+	[Test]
+	public async Task Default_empty_includes()
+	{
+		var repo = await CreateRepo();
+		await repo.AddAsync(new FakeEntity
+		{
+			Name = "Alpha",
+		});
+		await repo.AddAsync(new FakeEntity
+		{
+			Name = "Beta",
+		});
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		var spec = new IncludeOnlySpec(builder);
+		var result = await repo.ListAsync(spec);
+
+		await Assert.That(result).Count().IsEqualTo(2);
+	}
+
+	[Test]
+	public async Task Default_then_include_after_collection()
+	{
+		var dbContext = await CreateDbContext();
+		var repo = new Repository<FakeEntity>(dbContext);
+		var entity = new FakeEntity
+		{
+			Name = "Test",
+		};
+		entity.Details.Add(new FakeDetailEntity
+		{
+			Value = "detail",
+			DetailChildren =
+			{
+				new FakeDetailChildEntity
+				{
+					Value = "childDetail",
+				},
+			},
+		});
+		await repo.AddAsync(entity);
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		Expression<Func<FakeDetailEntity, List<FakeDetailChildEntity>>> expr = static d => d.DetailChildren;
+		builder.IncludeExpressions.Add(new IncludeExpressionInfo(
+			expr, typeof(FakeEntity), typeof(List<FakeDetailChildEntity>), typeof(IEnumerable<FakeDetailEntity>)));
+		var spec = new IncludeOnlySpec(builder);
+		var result = await repo.ListAsync(spec);
+
+		await Assert.That(result).Count().IsEqualTo(1);
+	}
+
+	// --- Cached evaluator (delegate-based) ---
+
+	[Test]
+	public async Task Cached_include_reference_nav()
+	{
+		var dbContext = await CreateDbContext();
+		var query = dbContext.FakeEntities.AsQueryable();
+		var entity = new FakeEntity
+		{
+			Name = "Test",
+			Child = new FakeChildEntity
+			{
+				Value = "child",
+			},
+		};
+		dbContext.FakeEntities.Add(entity);
+		await dbContext.SaveChangesAsync();
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child);
+		var spec = new IncludeOnlySpec(builder);
+
+		var result = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+
+		await Assert.That(result).Count().IsEqualTo(1);
+		await Assert.That(result[0].Name).IsEqualTo("Test");
+	}
+
+	[Test]
+	public async Task Cached_include_collection_nav()
+	{
+		var dbContext = await CreateDbContext();
+		var query = dbContext.FakeEntities.AsQueryable();
+		var entity = new FakeEntity
+		{
+			Name = "Test",
+		};
+		entity.Details.Add(new FakeDetailEntity
+		{
+			Value = "detail",
+		});
+		dbContext.FakeEntities.Add(entity);
+		await dbContext.SaveChangesAsync();
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Details);
+		var spec = new IncludeOnlySpec(builder);
+
+		var result = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+
+		await Assert.That(result).Count().IsEqualTo(1);
+	}
+
+	[Test]
+	public async Task Cached_then_include_after_reference()
+	{
+		var dbContext = await CreateDbContext();
+		var query = dbContext.FakeEntities.AsQueryable();
+		var entity = new FakeEntity
+		{
+			Name = "Test",
+			Child = new FakeChildEntity
+			{
+				Value = "child",
+				GrandChildren =
+				{
+					new FakeGrandChildEntity
+					{
+						Value = "grand",
+					},
+				},
+			},
+		};
+		dbContext.FakeEntities.Add(entity);
+		await dbContext.SaveChangesAsync();
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child).ThenInclude(static c => c.GrandChildren);
+		var spec = new IncludeOnlySpec(builder);
+
+		var result = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+
+		await Assert.That(result).Count().IsEqualTo(1);
+	}
+
+	[Test]
+	public async Task Cached_then_include_after_collection()
+	{
+		var dbContext = await CreateDbContext();
+		var query = dbContext.FakeEntities.AsQueryable();
+		var entity = new FakeEntity
+		{
+			Name = "Test",
+		};
+		entity.Details.Add(new FakeDetailEntity
+		{
+			Value = "detail",
+			DetailChildren =
+			{
+				new FakeDetailChildEntity
+				{
+					Value = "childDetail",
+				},
+			},
+		});
+		dbContext.FakeEntities.Add(entity);
+		await dbContext.SaveChangesAsync();
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		Expression<Func<FakeDetailEntity, List<FakeDetailChildEntity>>> expr = static d => d.DetailChildren;
+		builder.IncludeExpressions.Add(new IncludeExpressionInfo(
+			expr, typeof(FakeEntity), typeof(List<FakeDetailChildEntity>), typeof(IEnumerable<FakeDetailEntity>)));
+		var spec = new IncludeOnlySpec(builder);
+
+		var result = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+
+		await Assert.That(result).Count().IsEqualTo(1);
+	}
+
+	[Test]
+	public async Task Cached_empty_includes()
+	{
+		var dbContext = await CreateDbContext();
+		var query = dbContext.FakeEntities.AsQueryable();
+		dbContext.FakeEntities.AddRange(
+			new FakeEntity
+			{
+				Name = "Alpha",
+			},
+			new FakeEntity
+			{
+				Name = "Beta",
+			});
+		await dbContext.SaveChangesAsync();
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		var spec = new IncludeOnlySpec(builder);
+
+		var result = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+
+		await Assert.That(result).Count().IsEqualTo(2);
+	}
+
+	// --- Comparison ---
+
+	[Test]
+	public async Task Default_and_cached_produce_same_results()
+	{
+		var dbContext = await CreateDbContext();
+		var query = dbContext.FakeEntities.AsQueryable();
+		dbContext.FakeEntities.Add(new FakeEntity
+		{
+			Name = "Test",
+			Child = new FakeChildEntity
+			{
+				Value = "child",
+			},
+		});
+		await dbContext.SaveChangesAsync();
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child);
+		var spec = new IncludeOnlySpec(builder);
+
+		var resultDefault = IncludeEvaluator.Default.Evaluate(query, spec).ToList();
+		var resultCached = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+
+		await Assert.That(resultDefault).Count().IsEqualTo(1);
+		await Assert.That(resultCached).Count().IsEqualTo(1);
+		await Assert.That(resultDefault[0].Name).IsEqualTo(resultCached[0].Name);
+	}
+
+	// --- Cache reuse ---
+
+	[Test]
+	public async Task Cached_include_reuses_delegate()
+	{
+		var dbContext = await CreateDbContext();
+		var query = dbContext.FakeEntities.AsQueryable();
+		dbContext.FakeEntities.AddRange(
+			new FakeEntity
+			{
+				Name = "A",
+				Child = new FakeChildEntity
+				{
+					Value = "a",
+				},
+			},
+			new FakeEntity
+			{
+				Name = "B",
+				Child = new FakeChildEntity
+				{
+					Value = "b",
+				},
+			});
+		await dbContext.SaveChangesAsync();
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child);
+		var spec = new IncludeOnlySpec(builder);
+
+		_ = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+		var result = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+
+		await Assert.That(result).Count().IsEqualTo(2);
+	}
+
+	[Test]
+	public async Task Cached_then_include_reuses_delegate()
+	{
+		var dbContext = await CreateDbContext();
+		var query = dbContext.FakeEntities.AsQueryable();
+		dbContext.FakeEntities.AddRange(
+			new FakeEntity
+			{
+				Name = "A",
+				Child = new FakeChildEntity
+				{
+					Value = "a",
+					GrandChildren =
+					{
+						new FakeGrandChildEntity
+						{
+							Value = "g1",
+						},
+					},
+				},
+			},
+			new FakeEntity
+			{
+				Name = "B",
+				Child = new FakeChildEntity
+				{
+					Value = "b",
+					GrandChildren =
+					{
+						new FakeGrandChildEntity
+						{
+							Value = "g2",
+						},
+					},
+				},
+			});
+		await dbContext.SaveChangesAsync();
+
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child).ThenInclude(static c => c.GrandChildren);
+		var spec = new IncludeOnlySpec(builder);
+
+		_ = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+		var result = IncludeEvaluator.Cached.Evaluate(query, spec).ToList();
+
+		await Assert.That(result).Count().IsEqualTo(2);
+	}
+
+	private static async Task<Repository<FakeEntity>> CreateRepo()
+	{
+		var context = await CreateDbContext();
+		return new Repository<FakeEntity>(context);
+	}
+}

src/request.persistence.entityframeworkcore.tests/RepositoryTests.cs

@@ -0,0 +1,119 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using Microsoft.EntityFrameworkCore;
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class RepositoryTests
+{
+	private static async Task<FakeDbContext> CreateDbContext()
+	{
+		var options = new DbContextOptionsBuilder<FakeDbContext>()
+			.UseInMemoryDatabase($"TestDb_{Guid.NewGuid()}")
+			.EnableServiceProviderCaching(false)
+			.Options;
+
+		var context = new FakeDbContext(options);
+		await context.Database.EnsureCreatedAsync();
+		return context;
+	}
+
+	[Test]
+	public async Task AddAsync_persists_entity()
+	{
+		var context = await CreateDbContext();
+		var repo = new Repository<FakeEntity>(context);
+
+		var entity = new FakeEntity { Name = "Test" };
+		await repo.AddAsync(entity);
+
+		await Assert.That(entity.Id).IsNotEqualTo(Guid.Empty);
+		await Assert.That(entity.Name).IsEqualTo("Test");
+	}
+
+	[Test]
+	public async Task ListAsync_returns_all_entities()
+	{
+		var context = await CreateDbContext();
+		var repo = new Repository<FakeEntity>(context);
+
+		await repo.AddAsync(new FakeEntity { Name = "A" });
+		await repo.AddAsync(new FakeEntity { Name = "B" });
+
+		var list = await repo.ListAsync();
+
+		await Assert.That(list).Count().IsEqualTo(2);
+	}
+
+	[Test]
+	public async Task UpdateAsync_modifies_entity()
+	{
+		var context = await CreateDbContext();
+		var repo = new Repository<FakeEntity>(context);
+
+		var entity = new FakeEntity { Name = "Original" };
+		await repo.AddAsync(entity);
+
+		entity.Name = "Updated";
+		await repo.UpdateAsync(entity);
+
+		var all = await repo.ListAsync();
+		var found = all.FirstOrDefault(e => e.Id == entity.Id);
+		await Assert.That(found).IsNotNull();
+		await Assert.That(found!.Name).IsEqualTo("Updated");
+	}
+
+	[Test]
+	public async Task DeleteAsync_removes_entity()
+	{
+		var context = await CreateDbContext();
+		var repo = new Repository<FakeEntity>(context);
+
+		var entity = new FakeEntity { Name = "Test" };
+		await repo.AddAsync(entity);
+		await repo.DeleteAsync(entity);
+
+		var all = await repo.ListAsync();
+		var found = all.FirstOrDefault(e => e.Id == entity.Id);
+		await Assert.That(found).IsNull();
+	}
+
+	[Test]
+	public async Task CountAsync_returns_correct_count()
+	{
+		var context = await CreateDbContext();
+		var repo = new Repository<FakeEntity>(context);
+
+		await repo.AddAsync(new FakeEntity { Name = "A" });
+		await repo.AddAsync(new FakeEntity { Name = "B" });
+
+		var count = await repo.CountAsync();
+
+		await Assert.That(count).IsEqualTo(2);
+	}
+
+	[Test]
+	public async Task AnyAsync_returns_true_when_entities_exist()
+	{
+		var context = await CreateDbContext();
+		var repo = new Repository<FakeEntity>(context);
+
+		await repo.AddAsync(new FakeEntity { Name = "A" });
+
+		var any = await repo.AnyAsync();
+
+		await Assert.That(any).IsTrue();
+	}
+
+	[Test]
+	public async Task AnyAsync_returns_false_when_no_entities()
+	{
+		var context = await CreateDbContext();
+		var repo = new Repository<FakeEntity>(context);
+
+		var any = await repo.AnyAsync();
+
+		await Assert.That(any).IsFalse();
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/CombinedWhereOrderTakeSpec.cs

@@ -0,0 +1,15 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class CombinedWhereOrderTakeSpec : Specification<FakeEntity>
+{
+	public CombinedWhereOrderTakeSpec()
+	{
+		Query.Where(e => e.Name != "David")
+			 .OrderBy(e => e.Name)
+			 .Builder
+			 .Take(2);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/ConcurrentSelectorSpec.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class ConcurrentSelectorSpec : Specification<FakeEntity, string>
+{
+	public ConcurrentSelectorSpec()
+	{
+		Query.Select(e => e.Name);
+		Query.SelectMany(e => e.Name.Split(' '));
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/DuplicateOrderSpec.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class DuplicateOrderSpec : Specification<FakeEntity>
+{
+	public DuplicateOrderSpec()
+	{
+		Query.OrderBy(e => e.Name);
+		Query.OrderBy(e => e.Id);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/FakeChildEntity.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class FakeChildEntity
+{
+	public Guid Id { get; set; }
+	public string Value { get; set; } = string.Empty;
+	public Guid FakeEntityId { get; set; }
+	public FakeEntity FakeEntity { get; set; } = null!;
+	public List<FakeGrandChildEntity> GrandChildren { get; set; } = [];
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/FakeDbContext.cs

@@ -0,0 +1,60 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using Microsoft.EntityFrameworkCore;
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class FakeDbContext(DbContextOptions<FakeDbContext> options) : DbContext(options)
+{
+	public DbSet<FakeEntity> FakeEntities => Set<FakeEntity>();
+	public DbSet<FakeChildEntity> FakeChildEntities => Set<FakeChildEntity>();
+	public DbSet<FakeDetailEntity> FakeDetailEntities => Set<FakeDetailEntity>();
+	public DbSet<FakeGrandChildEntity> FakeGrandChildEntities => Set<FakeGrandChildEntity>();
+	public DbSet<FakeDetailChildEntity> FakeDetailChildEntities => Set<FakeDetailChildEntity>();
+
+	protected override void OnModelCreating(ModelBuilder modelBuilder)
+	{
+		modelBuilder.Entity<FakeEntity>(entity =>
+		{
+			entity.HasKey(static e => e.Id);
+			entity.Property(static e => e.Name).IsRequired();
+			entity.HasOne(static e => e.Child)
+				  .WithOne(static c => c.FakeEntity)
+				  .HasForeignKey<FakeChildEntity>(static c => c.FakeEntityId);
+			entity.HasMany(static e => e.Details)
+				  .WithOne(static d => d.FakeEntity)
+				  .HasForeignKey(static d => d.FakeEntityId);
+		});
+
+		modelBuilder.Entity<FakeChildEntity>(child =>
+		{
+			child.HasKey(static c => c.Id);
+			child.Property(static c => c.Value).IsRequired();
+			child.HasMany(static c => c.GrandChildren)
+				 .WithOne(static g => g.FakeChildEntity)
+				 .HasForeignKey(static g => g.FakeChildEntityId);
+		});
+
+		modelBuilder.Entity<FakeGrandChildEntity>(grandChild =>
+		{
+			grandChild.HasKey(static g => g.Id);
+			grandChild.Property(static g => g.Value).IsRequired();
+		});
+
+		modelBuilder.Entity<FakeDetailEntity>(detail =>
+		{
+			detail.HasKey(static d => d.Id);
+			detail.Property(static d => d.Value).IsRequired();
+			detail.HasMany(static d => d.DetailChildren)
+				  .WithOne(static dc => dc.FakeDetailEntity)
+				  .HasForeignKey(static dc => dc.FakeDetailEntityId);
+		});
+
+		modelBuilder.Entity<FakeDetailChildEntity>(detailChild =>
+		{
+			detailChild.HasKey(static d => d.Id);
+			detailChild.Property(static d => d.Value).IsRequired();
+		});
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/FakeDetailChildEntity.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class FakeDetailChildEntity
+{
+	public Guid Id { get; set; }
+	public string Value { get; set; } = string.Empty;
+	public Guid FakeDetailEntityId { get; set; }
+	public FakeDetailEntity FakeDetailEntity { get; set; } = null!;
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/FakeDetailEntity.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class FakeDetailEntity
+{
+	public Guid Id { get; set; }
+	public string Value { get; set; } = string.Empty;
+	public Guid FakeEntityId { get; set; }
+	public FakeEntity FakeEntity { get; set; } = null!;
+	public List<FakeDetailChildEntity> DetailChildren { get; set; } = [];
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/FakeEntity.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class FakeEntity
+{
+	public Guid Id { get; set; }
+	public string Name { get; set; } = string.Empty;
+	public FakeChildEntity Child { get; set; } = null!;
+	public List<FakeDetailEntity> Details { get; set; } = [];
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/FakeGrandChildEntity.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class FakeGrandChildEntity
+{
+	public Guid Id { get; set; }
+	public string Value { get; set; } = string.Empty;
+	public Guid FakeChildEntityId { get; set; }
+	public FakeChildEntity FakeChildEntity { get; set; } = null!;
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/FirstOrderedSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class FirstOrderedSpec : Specification<FakeEntity>
+{
+	public FirstOrderedSpec()
+	{
+		Query.OrderBy(e => e.Name);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/IncludeChildSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class IncludeChildSpec : Specification<FakeEntity>
+{
+	public IncludeChildSpec()
+	{
+		Query.Include(static e => e.Child);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/IncludeChildThenGrandChildrenSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class IncludeChildThenGrandChildrenSpec : Specification<FakeEntity>
+{
+	public IncludeChildThenGrandChildrenSpec()
+	{
+		Query.Include(static e => e.Child).ThenInclude(static c => c.GrandChildren);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/IncludeDetailsSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class IncludeDetailsSpec : Specification<FakeEntity>
+{
+	public IncludeDetailsSpec()
+	{
+		Query.Include(static e => e.Details);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/IncludeOnlySpec.cs

@@ -0,0 +1,11 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class IncludeOnlySpec : Specification<FakeEntity>
+{
+	public IncludeOnlySpec(SpecificationBuilder<FakeEntity> builder) : base(builder)
+	{
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/MultiSearchSpec.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class MultiSearchSpec : Specification<FakeEntity>
+{
+	public MultiSearchSpec(string term1, string term2)
+	{
+		Query.Search(e => e.Name, term1, searchGroup: 1)
+			 .Search(e => e.Name, term2, searchGroup: 1);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/MultipleWhereSpec.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class MultipleWhereSpec : Specification<FakeEntity>
+{
+	public MultipleWhereSpec()
+	{
+		Query.Where(e => e.Name.StartsWith("A"))
+			 .Where(e => e.Name.EndsWith("Beta"));
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/NameEqualSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class NameEqualSpec : Specification<FakeEntity>
+{
+	public NameEqualSpec(string name)
+	{
+		Query.Where(e => e.Name == name);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/NameProjectionSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class NameProjectionSpec : Specification<FakeEntity, string>
+{
+	public NameProjectionSpec()
+	{
+		Query.Select(e => e.Name);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/NoSelectorSpec.cs

@@ -0,0 +1,8 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class NoSelectorSpec : Specification<FakeEntity, string>
+{
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/OrderByNameDescSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class OrderByNameDescSpec : Specification<FakeEntity>
+{
+	public OrderByNameDescSpec()
+	{
+		Query.OrderByDescending(e => e.Name);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/OrderByNameSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class OrderByNameSpec : Specification<FakeEntity>
+{
+	public OrderByNameSpec()
+	{
+		Query.OrderBy(e => e.Name);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/OrderByNameThenByIdDescSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class OrderByNameThenByIdDescSpec : Specification<FakeEntity>
+{
+	public OrderByNameThenByIdDescSpec()
+	{
+		Query.OrderBy(e => e.Name).ThenByDescending(e => e.Id);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/OrderByNameThenByIdSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class OrderByNameThenByIdSpec : Specification<FakeEntity>
+{
+	public OrderByNameThenByIdSpec()
+	{
+		Query.OrderBy(e => e.Name).ThenBy(e => e.Id);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/OrderedSkipSpec.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class OrderedSkipSpec : Specification<FakeEntity>
+{
+	public OrderedSkipSpec(int skip)
+	{
+		Query.OrderBy(e => e.Name);
+		Query.Skip(skip);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/OrderedSkipTakeSpec.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class OrderedSkipTakeSpec : Specification<FakeEntity>
+{
+	public OrderedSkipTakeSpec(int skip, int take)
+	{
+		Query.OrderBy(e => e.Name);
+		Query.Skip(skip).Take(take);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/OrderedTakeSpec.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class OrderedTakeSpec : Specification<FakeEntity>
+{
+	public OrderedTakeSpec(int take)
+	{
+		Query.OrderBy(e => e.Name);
+		Query.Take(take);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/PostProcessingSpec.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class PostProcessingSpec : Specification<FakeEntity>
+{
+	public PostProcessingSpec()
+	{
+		Query.Where(e => e.Name.StartsWith("A"))
+			 .PostProcessing(items => items.Take(1));
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/SearchSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class SearchSpec : Specification<FakeEntity>
+{
+	public SearchSpec(string term, int searchGroup = 1)
+	{
+		Query.Search(e => e.Name, term, searchGroup: searchGroup);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/SkipOnlySpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class SkipOnlySpec : Specification<FakeEntity>
+{
+	public SkipOnlySpec(int skip)
+	{
+		Query.Skip(skip);
+	}
+}

src/request.persistence.entityframeworkcore.tests/_fixtures/WhereSpec.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore.Tests;
+
+internal sealed class WhereSpec : Specification<FakeEntity>
+{
+	public WhereSpec()
+	{
+		Query.Where(e => e.Name == "Alpha");
+	}
+}

src/request.persistence.entityframeworkcore/Geekeey.Request.Persistence.EntityFrameworkCore.csproj

@@ -0,0 +1,40 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <IsPackable>true</IsPackable>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup Condition="'$(Configuration)' == 'Debug'">
+    <InternalsVisibleTo Include="Geekeey.Request.Persistence.EntityFrameworkCore.Tests" />
+  </ItemGroup>
+
+  <PropertyGroup>
+    <PackageReadmeFile>package-readme.md</PackageReadmeFile>
+    <PackageDescription>Entity Framework Core implementation of the generic repository and specification pattern.</PackageDescription>
+    <PackageIcon>package-icon.png</PackageIcon>
+    <PackageProjectUrl>https://code.geekeey.de/geekeey/request/src/branch/main/src/request.persistence.entityframeworkcore</PackageProjectUrl>
+    <PackageLicenseExpression>EUPL-1.2</PackageLicenseExpression>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Include=".\package-icon.png" Pack="true" PackagePath="\" Visible="false" />
+    <None Include=".\package-readme.md" Pack="true" PackagePath="\" Visible="false" />
+    <None Include="..\..\LICENSE.md" Pack="true" PackagePath="\" Visible="false" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.EntityFrameworkCore" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Relational" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\request.persistence\Geekeey.Request.Persistence.csproj" />
+  </ItemGroup>
+
+</Project>

src/request.persistence.entityframeworkcore/Repository.cs

@@ -0,0 +1,174 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using Microsoft.EntityFrameworkCore;
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+/// <summary>
+/// Represents a repository for <typeparamref name="TEntity"/>.
+/// </summary>
+/// <typeparam name="TEntity">The type of entity.</typeparam>
+public partial class Repository<TEntity> : IRepository<TEntity>
+	where TEntity : class
+{
+	private readonly SpecificationEvaluator _evaluator = SpecificationEvaluator.Default;
+
+	/// <summary>
+	/// Creates a new repository.
+	/// </summary>
+	/// <param name="dbContext">The <see cref="DbContext"/> used by the repository.</param>
+	public Repository(DbContext dbContext)
+	{
+		DbContext = dbContext;
+	}
+
+	/// <summary>
+	/// Gets the <see cref="DbContext"/> used by the repository.
+	/// </summary>
+	protected DbContext DbContext { get; }
+
+	/// <inheritdoc />
+	public virtual async Task<TEntity?> FirstOrDefaultAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default)
+	{
+		return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task<TResult?> FirstOrDefaultAsync<TResult>(ISpecification<TEntity, TResult> specification, CancellationToken cancellationToken = default)
+	{
+		return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task<List<TEntity>> ListAsync(CancellationToken cancellationToken = default)
+	{
+		return await DbContext.Set<TEntity>().ToListAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task<List<TEntity>> ListAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default)
+	{
+		var queryResult = await ApplySpecification(specification).ToListAsync(cancellationToken);
+
+		return specification.PostProcessingAction is null
+			? queryResult
+			: [.. specification.PostProcessingAction(queryResult)];
+	}
+
+	/// <inheritdoc />
+	public virtual async Task<List<TResult>> ListAsync<TResult>(ISpecification<TEntity, TResult> specification, CancellationToken cancellationToken = default)
+	{
+		var queryResult = await ApplySpecification(specification).ToListAsync(cancellationToken);
+
+		return specification.PostProcessingAction is null
+			? queryResult
+			: [.. specification.PostProcessingAction(queryResult)];
+	}
+
+	/// <inheritdoc />
+	public virtual async Task<int> CountAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default)
+	{
+		return await ApplySpecification(specification, true).CountAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task<int> CountAsync(CancellationToken cancellationToken = default)
+	{
+		return await DbContext.Set<TEntity>().CountAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task<bool> AnyAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default)
+	{
+		return await ApplySpecification(specification, true).AnyAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task<bool> AnyAsync(CancellationToken cancellationToken = default)
+	{
+		return await DbContext.Set<TEntity>().AnyAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual IAsyncEnumerable<TEntity> AsAsyncEnumerable(ISpecification<TEntity> specification)
+	{
+		return ApplySpecification(specification).AsAsyncEnumerable();
+	}
+
+	protected virtual IQueryable<TEntity> ApplySpecification(ISpecification<TEntity> specification, bool evaluateCriteriaOnly = false)
+	{
+		return _evaluator.Evaluate(DbContext.Set<TEntity>(), specification, evaluateCriteriaOnly);
+	}
+
+	protected virtual IQueryable<TResult> ApplySpecification<TResult>(ISpecification<TEntity, TResult> specification)
+	{
+		return _evaluator.Evaluate(DbContext.Set<TEntity>(), specification);
+	}
+}
+
+public partial class Repository<TEntity>
+{
+	/// <inheritdoc />
+	public virtual async Task AddAsync(TEntity entity, CancellationToken cancellationToken = default)
+	{
+		DbContext.Set<TEntity>().Add(entity);
+
+		await SaveChangesAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task AddRangeAsync(IEnumerable<TEntity> entities, CancellationToken cancellationToken = default)
+	{
+		DbContext.Set<TEntity>().AddRange(entities);
+
+		await SaveChangesAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task UpdateAsync(TEntity entity, CancellationToken cancellationToken = default)
+	{
+		DbContext.Set<TEntity>().Update(entity);
+
+		await SaveChangesAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task UpdateRangeAsync(IEnumerable<TEntity> entities, CancellationToken cancellationToken = default)
+	{
+		DbContext.Set<TEntity>().UpdateRange(entities);
+
+		await SaveChangesAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task DeleteAsync(TEntity entity, CancellationToken cancellationToken = default)
+	{
+		DbContext.Set<TEntity>().Remove(entity);
+
+		await SaveChangesAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task DeleteRangeAsync(IEnumerable<TEntity> entities, CancellationToken cancellationToken = default)
+	{
+		DbContext.Set<TEntity>().RemoveRange(entities);
+
+		await SaveChangesAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task DeleteRangeAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default)
+	{
+		var query = ApplySpecification(specification);
+		DbContext.Set<TEntity>().RemoveRange(query);
+
+		await SaveChangesAsync(cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public virtual async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
+	{
+		return await DbContext.SaveChangesAsync(cancellationToken);
+	}
+}

src/request.persistence.entityframeworkcore/_Specification/SpecificationEvaluator.cs

@@ -0,0 +1,60 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+internal sealed class SpecificationEvaluator
+{
+	private readonly IReadOnlyList<IEvaluator> _evaluators;
+
+	public static SpecificationEvaluator Default { get; } = new();
+
+	private SpecificationEvaluator(bool cache = false)
+	{
+		_evaluators =
+		[
+			WhereEvaluator.Instance,
+			cache ? IncludeEvaluator.Cached : IncludeEvaluator.Default,
+			SearchEvaluator.Instance,
+			OrderEvaluator.Instance,
+			PaginationEvaluator.Instance
+		];
+	}
+
+	public IQueryable<TResult> Evaluate<T, TResult>(IQueryable<T> query, ISpecification<T, TResult> specification)
+		where T : class
+	{
+		ArgumentNullException.ThrowIfNull(specification);
+
+		if (specification.Selector is null && specification.SelectorMany is null)
+		{
+			throw new SelectorNotFoundException();
+		}
+
+		if (specification.Selector is not null && specification.SelectorMany is not null)
+		{
+			throw new ConcurrentSelectorsException();
+		}
+
+		query = Evaluate<T>(query, specification);
+
+		return specification.Selector is not null
+			? query.Select(specification.Selector)
+			: query.SelectMany(specification.SelectorMany!);
+	}
+
+	public IQueryable<T> Evaluate<T>(IQueryable<T> query, ISpecification<T> specification, bool evaluateCriteriaOnly = false)
+		where T : class
+	{
+		ArgumentNullException.ThrowIfNull(specification);
+
+		var evaluators = evaluateCriteriaOnly ? _evaluators.Where(static instance => instance.IsCriteriaEvaluator) : _evaluators;
+
+		foreach (var evaluator in evaluators)
+		{
+			query = evaluator.Evaluate(query, specification);
+		}
+
+		return query;
+	}
+}

src/request.persistence.entityframeworkcore/_Specification/_evaluators/IEvaluator.cs

@@ -0,0 +1,25 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+/// <summary>
+/// Defines an evaluator that applies a specific aspect of a specification to a query.
+/// </summary>
+public interface IEvaluator
+{
+	/// <summary>
+	/// Gets a value indicating whether this evaluator filters the result set (criteria)
+	/// rather than shaping the query (e.g., includes, ordering, pagination).
+	/// </summary>
+	bool IsCriteriaEvaluator { get; }
+
+	/// <summary>
+	/// Applies the evaluator's logic to the specified query based on the given specification.
+	/// </summary>
+	/// <typeparam name="T">The type of entity being queried.</typeparam>
+	/// <param name="query">The query to evaluate.</param>
+	/// <param name="specification">The specification containing the expression to apply.</param>
+	/// <returns>The modified query.</returns>
+	IQueryable<T> Evaluate<T>(IQueryable<T> query, ISpecification<T> specification) where T : class;
+}

src/request.persistence.entityframeworkcore/_Specification/_evaluators/IncludeEvaluator.cs

@@ -0,0 +1,173 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Collections.Concurrent;
+using System.Linq.Expressions;
+using System.Reflection;
+
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Query;
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+internal sealed class IncludeEvaluator : IEvaluator
+{
+	private static readonly MethodInfo IncludeMethodInfo
+		= typeof(EntityFrameworkQueryableExtensions)
+			.GetTypeInfo().GetDeclaredMethods(nameof(EntityFrameworkQueryableExtensions.Include))
+			.Single(static mi =>
+				mi.GetGenericArguments().Length is 2 &&
+				mi.GetParameters()[0].ParameterType.GetGenericTypeDefinition() == typeof(IQueryable<>) &&
+				mi.GetParameters()[1].ParameterType.GetGenericTypeDefinition() == typeof(Expression<>));
+
+	private static readonly MethodInfo ThenIncludeAfterReferenceMethodInfo
+		= typeof(EntityFrameworkQueryableExtensions)
+			.GetTypeInfo().GetDeclaredMethods(nameof(EntityFrameworkQueryableExtensions.ThenInclude))
+			.Where(static mi => mi.GetGenericArguments().Length is 3)
+			.Single(static mi =>
+				mi.GetParameters()[0].ParameterType.GenericTypeArguments[1].IsGenericParameter &&
+				mi.GetParameters()[0].ParameterType.GetGenericTypeDefinition() == typeof(IIncludableQueryable<,>) &&
+				mi.GetParameters()[1].ParameterType.GetGenericTypeDefinition() == typeof(Expression<>));
+
+	private static readonly MethodInfo ThenIncludeAfterEnumerableMethodInfo
+		= typeof(EntityFrameworkQueryableExtensions)
+			.GetTypeInfo().GetDeclaredMethods(nameof(EntityFrameworkQueryableExtensions.ThenInclude))
+			.Where(static mi => mi.GetGenericArguments().Length is 3)
+			.Single(static mi =>
+			{
+				var typeInfo = mi.GetParameters()[0].ParameterType.GenericTypeArguments[1];
+
+				return typeInfo.IsGenericType &&
+					   typeInfo.GetGenericTypeDefinition() == typeof(IEnumerable<>) &&
+					   mi.GetParameters()[0].ParameterType.GetGenericTypeDefinition() == typeof(IIncludableQueryable<,>) &&
+					   mi.GetParameters()[1].ParameterType.GetGenericTypeDefinition() == typeof(Expression<>);
+			});
+
+	private static readonly ConcurrentDictionary<(Type EntityType, Type PropertyType, Type? PreviousPropertyType), Lazy<Func<IQueryable, LambdaExpression, IQueryable>>> DelegatesCache = new();
+
+	private readonly bool _cacheEnabled;
+
+	private IncludeEvaluator(bool cacheEnabled)
+	{
+		_cacheEnabled = cacheEnabled;
+	}
+
+	public static IncludeEvaluator Default { get; } = new(false);
+
+	public static IncludeEvaluator Cached { get; } = new(true);
+
+	public bool IsCriteriaEvaluator => false;
+
+	public IQueryable<T> Evaluate<T>(IQueryable<T> query, ISpecification<T> specification) where T : class
+	{
+		foreach (var includeInfo in specification.IncludeExpressions)
+		{
+			if (includeInfo.Type == IncludeType.Include)
+			{
+				query = BuildInclude<T>(query, includeInfo);
+			}
+			else if (includeInfo.Type == IncludeType.ThenInclude)
+			{
+				query = BuildThenInclude<T>(query, includeInfo);
+			}
+		}
+
+		return query;
+	}
+
+	private IQueryable<T> BuildInclude<T>(IQueryable query, IncludeExpressionInfo includeInfo)
+	{
+		if (!_cacheEnabled)
+		{
+			var result = IncludeMethodInfo.MakeGenericMethod(includeInfo.EntityType, includeInfo.PropertyType)
+				.Invoke(null, [query, includeInfo.LambdaExpression]);
+
+			_ = result ?? throw new TargetException();
+
+			return (IQueryable<T>)result;
+		}
+
+		var include = DelegatesCache.GetOrAdd((includeInfo.EntityType, includeInfo.PropertyType, null), CreateIncludeDelegate).Value;
+
+		return (IQueryable<T>)include(query, includeInfo.LambdaExpression);
+	}
+
+	private static Lazy<Func<IQueryable, LambdaExpression, IQueryable>> CreateIncludeDelegate((Type EntityType, Type PropertyType, Type? PreviousPropertyType) cacheKey)
+	{
+		return new Lazy<Func<IQueryable, LambdaExpression, IQueryable>>(() =>
+		{
+			var concreteInclude = IncludeMethodInfo.MakeGenericMethod(cacheKey.EntityType, cacheKey.PropertyType);
+			var sourceParameter = Expression.Parameter(typeof(IQueryable));
+			var selectorParameter = Expression.Parameter(typeof(LambdaExpression));
+
+			var call = Expression.Call(concreteInclude,
+				Expression.Convert(sourceParameter, typeof(IQueryable<>).MakeGenericType(cacheKey.EntityType)),
+				Expression.Convert(selectorParameter, typeof(Expression<>).MakeGenericType(typeof(Func<,>).MakeGenericType(cacheKey.EntityType, cacheKey.PropertyType))));
+
+			var lambda = Expression.Lambda<Func<IQueryable, LambdaExpression, IQueryable>>(call, sourceParameter, selectorParameter);
+
+			return lambda.Compile();
+		});
+	}
+
+	private IQueryable<T> BuildThenInclude<T>(IQueryable query, IncludeExpressionInfo includeInfo)
+	{
+		ArgumentNullException.ThrowIfNull(includeInfo.PreviousPropertyType);
+
+		if (!_cacheEnabled)
+		{
+			var result = (IsGenericEnumerable(includeInfo.PreviousPropertyType, out var previousPropertyType)
+					? ThenIncludeAfterEnumerableMethodInfo
+					: ThenIncludeAfterReferenceMethodInfo).MakeGenericMethod(includeInfo.EntityType, previousPropertyType, includeInfo.PropertyType)
+				.Invoke(null, [query, includeInfo.LambdaExpression]);
+
+			_ = result ?? throw new TargetException();
+
+			return (IQueryable<T>)result;
+		}
+
+		var thenInclude = DelegatesCache.GetOrAdd((includeInfo.EntityType, includeInfo.PropertyType, includeInfo.PreviousPropertyType), CreateThenIncludeDelegate).Value;
+
+		return (IQueryable<T>)thenInclude(query, includeInfo.LambdaExpression);
+	}
+
+	private static Lazy<Func<IQueryable, LambdaExpression, IQueryable>> CreateThenIncludeDelegate((Type EntityType, Type PropertyType, Type? PreviousPropertyType) cacheKey)
+	{
+		return new Lazy<Func<IQueryable, LambdaExpression, IQueryable>>(() =>
+		{
+			ArgumentNullException.ThrowIfNull(cacheKey.PreviousPropertyType);
+
+			var thenIncludeInfo = ThenIncludeAfterReferenceMethodInfo;
+			if (IsGenericEnumerable(cacheKey.PreviousPropertyType, out var previousPropertyType))
+			{
+				thenIncludeInfo = ThenIncludeAfterEnumerableMethodInfo;
+			}
+
+			var concreteThenInclude = thenIncludeInfo.MakeGenericMethod(cacheKey.EntityType, previousPropertyType, cacheKey.PropertyType);
+			var sourceParameter = Expression.Parameter(typeof(IQueryable));
+			var selectorParameter = Expression.Parameter(typeof(LambdaExpression));
+
+			var call = Expression.Call(concreteThenInclude,
+				Expression.Convert(sourceParameter, typeof(IIncludableQueryable<,>).MakeGenericType(cacheKey.EntityType, cacheKey.PreviousPropertyType)),
+				Expression.Convert(selectorParameter, typeof(Expression<>).MakeGenericType(typeof(Func<,>).MakeGenericType(previousPropertyType, cacheKey.PropertyType))));
+
+			var lambda = Expression.Lambda<Func<IQueryable, LambdaExpression, IQueryable>>(call, sourceParameter, selectorParameter);
+
+			return lambda.Compile();
+		});
+	}
+
+	private static bool IsGenericEnumerable(Type type, out Type propertyType)
+	{
+		if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(IEnumerable<>))
+		{
+			propertyType = type.GenericTypeArguments[0];
+
+			return true;
+		}
+
+		propertyType = type;
+
+		return false;
+	}
+}

src/request.persistence.entityframeworkcore/_Specification/_evaluators/OrderEvaluator.cs

@@ -0,0 +1,43 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using Geekeey.Request.Persistence.EntityFrameworkCore;
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+internal sealed class OrderEvaluator : IEvaluator
+{
+	private OrderEvaluator() { }
+
+	internal static OrderEvaluator Instance { get; } = new();
+
+	public bool IsCriteriaEvaluator { get; }
+
+	public IQueryable<T> Evaluate<T>(IQueryable<T> query, ISpecification<T> specification) where T : class
+	{
+		if (specification.OrderExpressions.Count(static info => info.OrderType is OrderType.OrderBy or OrderType.OrderByDescending) > 1)
+		{
+			throw new DuplicateOrderChainException();
+		}
+
+		IOrderedQueryable<T>? orderedQuery = null;
+		foreach (var orderExpression in specification.OrderExpressions)
+		{
+			orderedQuery = orderExpression.OrderType switch
+			{
+				OrderType.OrderBy => query.OrderBy(orderExpression.KeySelector),
+				OrderType.OrderByDescending => query.OrderByDescending(orderExpression.KeySelector),
+				OrderType.ThenBy => orderedQuery!.ThenBy(orderExpression.KeySelector),
+				OrderType.ThenByDescending => orderedQuery!.ThenByDescending(orderExpression.KeySelector),
+				_ => orderedQuery
+			};
+		}
+
+		if (orderedQuery is not null)
+		{
+			query = orderedQuery;
+		}
+
+		return query;
+	}
+}

src/request.persistence.entityframeworkcore/_Specification/_evaluators/PaginationEvaluator.cs

@@ -0,0 +1,28 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+internal sealed class PaginationEvaluator : IEvaluator
+{
+	private PaginationEvaluator() { }
+
+	public static PaginationEvaluator Instance { get; } = new();
+
+	public bool IsCriteriaEvaluator { get; }
+
+	public IQueryable<T> Evaluate<T>(IQueryable<T> query, ISpecification<T> specification) where T : class
+	{
+		if (specification.Skip is not null and not 0)
+		{
+			query = query.Skip(specification.Skip.Value);
+		}
+
+		if (specification.Take is not null)
+		{
+			query = query.Take(specification.Take.Value);
+		}
+
+		return query;
+	}
+}

src/request.persistence.entityframeworkcore/_Specification/_evaluators/SearchEvaluator.cs

@@ -0,0 +1,81 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+using System.Reflection;
+
+using Microsoft.EntityFrameworkCore;
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+internal sealed class SearchEvaluator : IEvaluator
+{
+	private static readonly MemberExpression Functions
+		= Expression.Property(null, typeof(EF).GetProperty(nameof(EF.Functions)) ?? throw new TargetException("The EF.Functions not found!"));
+
+	private static readonly MethodInfo LikeMethodInfo
+		= typeof(DbFunctionsExtensions).GetMethod(nameof(DbFunctionsExtensions.Like), [typeof(DbFunctions), typeof(string), typeof(string)])
+		  ?? throw new TargetException("The EF.Functions.Like not found");
+
+	private SearchEvaluator() { }
+
+	public static SearchEvaluator Instance { get; } = new();
+
+	public bool IsCriteriaEvaluator { get; } = true;
+
+	public IQueryable<T> Evaluate<T>(IQueryable<T> query, ISpecification<T> specification) where T : class
+	{
+		foreach (var searchCriteria in specification.SearchCriteria.GroupBy(static info => info.SearchGroup))
+		{
+			query = Search(query, searchCriteria);
+		}
+
+		return query;
+	}
+
+	private static IQueryable<T> Search<T>(IQueryable<T> source, IEnumerable<SearchExpressionInfo<T>> criteria)
+	{
+		Expression? expr = null;
+		var parameter = Expression.Parameter(typeof(T), "x");
+
+		foreach (var info in criteria)
+		{
+			if (string.IsNullOrEmpty(info.SearchTerm))
+			{
+				continue;
+			}
+
+			LambdaExpression selector = info.Selector;
+			selector = ParameterReplacerVisitor.Replace(selector, info.Selector.Parameters[0], parameter);
+
+			var expression = ((Expression<Func<string>>)(() => info.SearchTerm)).Body;
+			var likeExpression = Expression.Call(null, LikeMethodInfo, Functions, selector.Body, expression);
+
+			expr = expr is null ? likeExpression : Expression.OrElse(expr, likeExpression);
+		}
+
+		return expr is null ? source : source.Where(Expression.Lambda<Func<T, bool>>(expr, parameter));
+	}
+
+	private sealed class ParameterReplacerVisitor : ExpressionVisitor
+	{
+		private readonly Expression _newExpression;
+		private readonly ParameterExpression _oldParameter;
+
+		private ParameterReplacerVisitor(ParameterExpression oldParameter, Expression newExpression)
+		{
+			_oldParameter = oldParameter;
+			_newExpression = newExpression;
+		}
+
+		internal static T Replace<T>(T expression, ParameterExpression oldParameter, Expression newExpression) where T : Expression
+		{
+			return (T)new ParameterReplacerVisitor(oldParameter, newExpression).Visit(expression);
+		}
+
+		protected override Expression VisitParameter(ParameterExpression expression)
+		{
+			return expression == _oldParameter ? _newExpression : expression;
+		}
+	}
+}

src/request.persistence.entityframeworkcore/_Specification/_evaluators/WhereEvaluator.cs

@@ -0,0 +1,23 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+internal sealed class WhereEvaluator : IEvaluator
+{
+	private WhereEvaluator() { }
+
+	internal static WhereEvaluator Instance { get; } = new();
+
+	public bool IsCriteriaEvaluator { get; } = true;
+
+	public IQueryable<T> Evaluate<T>(IQueryable<T> query, ISpecification<T> specification) where T : class
+	{
+		foreach (var info in specification.WhereExpressions)
+		{
+			query = query.Where(info.Filter);
+		}
+
+		return query;
+	}
+}

src/request.persistence.entityframeworkcore/_Specification/_exceptions/ConcurrentSelectorsException.cs

@@ -0,0 +1,33 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+/// <summary>
+/// Represents an error that occurs when a specification defines both <c>Select()</c> and <c>SelectMany()</c> transforms.
+/// </summary>
+/// <remarks>
+/// Only one selector transform is permitted per specification.
+/// </remarks>
+public sealed class ConcurrentSelectorsException : Exception
+{
+	private const string ExceptionMessage = "Concurrent specification selector transforms defined. Ensure only one of the Select() or SelectMany() transforms is used in the same specification!";
+
+	/// <summary>
+	/// Initializes a new instance of the <see cref="ConcurrentSelectorsException"/> class.
+	/// </summary>
+	public ConcurrentSelectorsException()
+		: base(ExceptionMessage)
+	{
+	}
+
+	/// <summary>
+	/// Initializes a new instance of the <see cref="ConcurrentSelectorsException"/> class with a reference
+	/// to the inner exception that is the cause of this exception.
+	/// </summary>
+	/// <param name="innerException">The exception that is the cause of the current exception.</param>
+	public ConcurrentSelectorsException(Exception innerException)
+		: base(ExceptionMessage, innerException)
+	{
+	}
+}

src/request.persistence.entityframeworkcore/_Specification/_exceptions/DuplicateOrderChainException.cs

@@ -0,0 +1,34 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+/// <summary>
+/// Represents an error that occurs when a specification contains more than one ordering chain.
+/// </summary>
+/// <remarks>
+/// Only a single <c>OrderBy()</c> or <c>OrderByDescending()</c> clause is permitted per specification.
+/// Subsequent ordering must use <c>ThenBy()</c> or <c>ThenByDescending()</c>.
+/// </remarks>
+public sealed class DuplicateOrderChainException : Exception
+{
+	private const string ExceptionMessage = "The specification contains more than one Order chain!";
+
+	/// <summary>
+	/// Initializes a new instance of the <see cref="DuplicateOrderChainException"/> class.
+	/// </summary>
+	public DuplicateOrderChainException()
+		: base(ExceptionMessage)
+	{
+	}
+
+	/// <summary>
+	/// Initializes a new instance of the <see cref="DuplicateOrderChainException"/> class with a reference
+	/// to the inner exception that is the cause of this exception.
+	/// </summary>
+	/// <param name="innerException">The exception that is the cause of the current exception.</param>
+	public DuplicateOrderChainException(Exception innerException)
+		: base(ExceptionMessage, innerException)
+	{
+	}
+}

src/request.persistence.entityframeworkcore/_Specification/_exceptions/SelectorNotFoundException.cs

@@ -0,0 +1,33 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.EntityFrameworkCore;
+
+/// <summary>
+/// Represents an error that occurs when a specification has no selector transform defined.
+/// </summary>
+/// <remarks>
+/// A specification targeting a projected result must define either <c>Select()</c> or <c>SelectMany()</c>.
+/// </remarks>
+public sealed class SelectorNotFoundException : Exception
+{
+	private const string ExceptionMessage = "The specification must have a selector transform defined. Ensure either Select() or SelectMany() is used in the specification!";
+
+	/// <summary>
+	/// Initializes a new instance of the <see cref="SelectorNotFoundException"/> class.
+	/// </summary>
+	public SelectorNotFoundException()
+		: base(ExceptionMessage)
+	{
+	}
+
+	/// <summary>
+	/// Initializes a new instance of the <see cref="SelectorNotFoundException"/> class with a reference
+	/// to the inner exception that is the cause of this exception.
+	/// </summary>
+	/// <param name="innerException">The exception that is the cause of the current exception.</param>
+	public SelectorNotFoundException(Exception innerException)
+		: base(ExceptionMessage, innerException)
+	{
+	}
+}

src/request.persistence.tests/.editorconfig

@@ -0,0 +1,8 @@
+
+[*.{cs,vb}]
+dotnet_diagnostic.CA1822.severity = none
+dotnet_diagnostic.CA1707.severity = none
+dotnet_diagnostic.IDE0060.severity = none
+dotnet_diagnostic.IDE0005.severity = none
+dotnet_diagnostic.IDE0390.severity = none
+dotnet_diagnostic.IDE0391.severity = none

src/request.persistence.tests/Geekeey.Request.Persistence.Tests.csproj

@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="TUnit" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <AssemblyAttribute Include="System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverageAttribute" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\request.persistence\Geekeey.Request.Persistence.csproj" />
+  </ItemGroup>
+
+</Project>

src/request.persistence.tests/SpecificationBuilderTests.cs

@@ -0,0 +1,216 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.Tests;
+
+internal sealed class SpecificationBuilderTests
+{
+	[Test]
+	public async Task Where_adds_filter()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Where(static x => x.Name == "test");
+
+		await Assert.That(builder.WhereExpressions).Count().IsEqualTo(1);
+	}
+
+	[Test]
+	public async Task Where_with_false_condition_does_not_add_filter()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Where(static x => x.Name == "test", false);
+
+		await Assert.That(builder.WhereExpressions).IsEmpty();
+	}
+
+	[Test]
+	public async Task OrderBy_adds_order_expression()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.OrderBy(static x => x.Name);
+
+		await Assert.That(builder.OrderExpressions).Count().IsEqualTo(1);
+		await Assert.That(builder.OrderExpressions[0].OrderType).IsEqualTo(OrderType.OrderBy);
+	}
+
+	[Test]
+	public async Task OrderByDescending_adds_order_expression()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.OrderByDescending(static x => x.Name);
+
+		await Assert.That(builder.OrderExpressions).Count().IsEqualTo(1);
+		await Assert.That(builder.OrderExpressions[0].OrderType).IsEqualTo(OrderType.OrderByDescending);
+	}
+
+	[Test]
+	public async Task ThenBy_after_order_by_chains_correctly()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.OrderBy(static x => x.Name).ThenBy(static x => x.Id);
+
+		await Assert.That(builder.OrderExpressions).Count().IsEqualTo(2);
+		await Assert.That(builder.OrderExpressions[0].OrderType).IsEqualTo(OrderType.OrderBy);
+		await Assert.That(builder.OrderExpressions[1].OrderType).IsEqualTo(OrderType.ThenBy);
+	}
+
+	[Test]
+	public async Task ThenByDescending_after_order_by_chains_correctly()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.OrderBy(static x => x.Name).ThenByDescending(static x => x.Id);
+
+		await Assert.That(builder.OrderExpressions).Count().IsEqualTo(2);
+		await Assert.That(builder.OrderExpressions[1].OrderType).IsEqualTo(OrderType.ThenByDescending);
+	}
+
+	[Test]
+	public async Task Take_sets_value()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Take(10);
+
+		await Assert.That(builder.Take).IsEqualTo(10);
+	}
+
+	[Test]
+	public async Task DuplicateTake_throws()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Take(10);
+
+		await Assert.That(() => builder.Take(5)).Throws<DuplicateTakeException>();
+	}
+
+	[Test]
+	public async Task Skip_sets_value()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Skip(5);
+
+		await Assert.That(builder.Skip).IsEqualTo(5);
+	}
+
+	[Test]
+	public async Task DuplicateSkip_throws()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Skip(5);
+
+		await Assert.That(() => builder.Skip(10)).Throws<DuplicateSkipException>();
+	}
+
+	[Test]
+	public async Task Include_adds_include_expression()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static x => x.Name);
+
+		await Assert.That(builder.IncludeExpressions).Count().IsEqualTo(1);
+	}
+
+	[Test]
+	public async Task Include_on_reference_navigation_adds_expression()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child);
+
+		await Assert.That(builder.IncludeExpressions).Count().IsEqualTo(1);
+		await Assert.That(builder.IncludeExpressions[0].Type).IsEqualTo(IncludeType.Include);
+		await Assert.That(builder.IncludeExpressions[0].EntityType).IsEqualTo(typeof(FakeEntity));
+		await Assert.That(builder.IncludeExpressions[0].PropertyType).IsEqualTo(typeof(FakeChildEntity));
+	}
+
+	[Test]
+	public async Task Include_on_collection_navigation_adds_expression()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Details);
+
+		await Assert.That(builder.IncludeExpressions).Count().IsEqualTo(1);
+		await Assert.That(builder.IncludeExpressions[0].Type).IsEqualTo(IncludeType.Include);
+		await Assert.That(builder.IncludeExpressions[0].EntityType).IsEqualTo(typeof(FakeEntity));
+		await Assert.That(builder.IncludeExpressions[0].PropertyType).IsEqualTo(typeof(List<FakeDetailEntity>));
+	}
+
+	[Test]
+	public async Task Include_with_false_condition_does_not_add_expression()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child, false);
+
+		await Assert.That(builder.IncludeExpressions).IsEmpty();
+	}
+
+	[Test]
+	public async Task ThenInclude_after_reference_navigation_adds_expression()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child).ThenInclude(static c => c.Value);
+
+		await Assert.That(builder.IncludeExpressions).Count().IsEqualTo(2);
+		await Assert.That(builder.IncludeExpressions[0].Type).IsEqualTo(IncludeType.Include);
+		await Assert.That(builder.IncludeExpressions[1].Type).IsEqualTo(IncludeType.ThenInclude);
+		await Assert.That(builder.IncludeExpressions[1].PreviousPropertyType).IsEqualTo(typeof(FakeChildEntity));
+	}
+
+	[Test]
+	public async Task ThenInclude_with_false_condition_does_not_add_expression()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child).ThenInclude(static c => c.Value, false);
+
+		await Assert.That(builder.IncludeExpressions).Count().IsEqualTo(1);
+		await Assert.That(builder.IncludeExpressions[0].Type).IsEqualTo(IncludeType.Include);
+	}
+
+	[Test]
+	public async Task Include_chains_ThenInclude_multiple_levels()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Include(static e => e.Child).ThenInclude(static c => c.FakeEntity).ThenInclude(static fe => fe.Details);
+
+		await Assert.That(builder.IncludeExpressions).Count().IsEqualTo(3);
+		await Assert.That(builder.IncludeExpressions[0].Type).IsEqualTo(IncludeType.Include);
+		await Assert.That(builder.IncludeExpressions[1].Type).IsEqualTo(IncludeType.ThenInclude);
+		await Assert.That(builder.IncludeExpressions[2].Type).IsEqualTo(IncludeType.ThenInclude);
+		await Assert.That(builder.IncludeExpressions[2].PreviousPropertyType).IsEqualTo(typeof(FakeEntity));
+	}
+
+	[Test]
+	public async Task ThenInclude_on_discarded_chain_does_not_add_expression()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		var includable = builder.Include(static e => e.Child, false);
+		includable.ThenInclude(static c => c.Value);
+
+		await Assert.That(builder.IncludeExpressions).IsEmpty();
+	}
+
+	[Test]
+	public async Task Select_sets_selector()
+	{
+		var builder = new SpecificationBuilder<FakeEntity, string>();
+		builder.Select(static x => x.Name);
+
+		await Assert.That(builder.Selector).IsNotNull();
+	}
+
+	[Test]
+	public async Task PostProcessing_sets_action()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.PostProcessing(static items => items.Where(static x => x.Name.Length > 0));
+
+		await Assert.That(builder.PostProcessingAction).IsNotNull();
+	}
+
+	[Test]
+	public async Task Search_adds_criteria()
+	{
+		var builder = new SpecificationBuilder<FakeEntity>();
+		builder.Search(static x => x.Name, "test");
+
+		await Assert.That(builder.SearchCriteria).Count().IsEqualTo(1);
+	}
+}

src/request.persistence.tests/_fixtures/FakeChildEntity.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.Tests;
+
+internal sealed class FakeChildEntity
+{
+	public Guid Id { get; set; }
+	public string Value { get; set; } = string.Empty;
+	public Guid FakeEntityId { get; set; }
+	public FakeEntity FakeEntity { get; set; } = null!;
+	public List<FakeGrandChildEntity> GrandChildren { get; set; } = [];
+}

src/request.persistence.tests/_fixtures/FakeDetailChildEntity.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.Tests;
+
+internal sealed class FakeDetailChildEntity
+{
+	public Guid Id { get; set; }
+	public string Value { get; set; } = string.Empty;
+	public Guid FakeDetailEntityId { get; set; }
+	public FakeDetailEntity FakeDetailEntity { get; set; } = null!;
+}

src/request.persistence.tests/_fixtures/FakeDetailEntity.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.Tests;
+
+internal sealed class FakeDetailEntity
+{
+	public Guid Id { get; set; }
+	public string Value { get; set; } = string.Empty;
+	public Guid FakeEntityId { get; set; }
+	public FakeEntity FakeEntity { get; set; } = null!;
+	public List<FakeDetailChildEntity> DetailChildren { get; set; } = [];
+}

src/request.persistence.tests/_fixtures/FakeEntity.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.Tests;
+
+internal sealed class FakeEntity
+{
+	public Guid Id { get; set; }
+	public string Name { get; set; } = string.Empty;
+	public FakeChildEntity Child { get; set; } = null!;
+	public List<FakeDetailEntity> Details { get; set; } = [];
+}

src/request.persistence.tests/_fixtures/FakeGrandChildEntity.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.Tests;
+
+internal sealed class FakeGrandChildEntity
+{
+	public Guid Id { get; set; }
+	public string Value { get; set; } = string.Empty;
+	public Guid FakeChildEntityId { get; set; }
+	public FakeChildEntity FakeChildEntity { get; set; } = null!;
+}

src/request.persistence.tests/_fixtures/FakeSpecification.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.Tests;
+
+internal sealed class FakeSpecification : Specification<FakeEntity>
+{
+	public FakeSpecification()
+	{
+		Query.Where(static x => x.Name.Length > 0);
+	}
+}

src/request.persistence.tests/_fixtures/FakeSpecificationWithResult.cs

@@ -0,0 +1,13 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.Tests;
+
+internal sealed class FakeSpecificationWithResult : Specification<FakeEntity, string>
+{
+	public FakeSpecificationWithResult()
+	{
+		Query.Where(static x => x.Name.Length > 0);
+		Query.Select(static x => x.Name);
+	}
+}

src/request.persistence.tests/_fixtures/SpecificationTestBuilder.cs

@@ -0,0 +1,8 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence.Tests;
+
+internal sealed class SpecificationTestBuilder : Specification<FakeEntity>
+{
+}

src/request.persistence/Geekeey.Request.Persistence.csproj

@@ -0,0 +1,31 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <IsPackable>true</IsPackable>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup Condition="'$(Configuration)' == 'Debug'">
+    <InternalsVisibleTo Include="Geekeey.Request.Persistence.Tests" />
+  </ItemGroup>
+
+  <PropertyGroup>
+    <PackageReadmeFile>package-readme.md</PackageReadmeFile>
+    <PackageDescription>Generic repository and specification pattern abstractions for .NET.</PackageDescription>
+    <PackageIcon>package-icon.png</PackageIcon>
+    <PackageProjectUrl>https://code.geekeey.de/geekeey/request/src/branch/main/src/request.persistence</PackageProjectUrl>
+    <PackageLicenseExpression>EUPL-1.2</PackageLicenseExpression>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Include=".\package-icon.png" Pack="true" PackagePath="\" Visible="false" />
+    <None Include=".\package-readme.md" Pack="true" PackagePath="\" Visible="false" />
+    <None Include="..\..\LICENSE.md" Pack="true" PackagePath="\" Visible="false" />
+  </ItemGroup>
+
+</Project>

src/request.persistence/IRepository.cs

@@ -0,0 +1,155 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Defines query operations for entities of type <typeparamref name="TEntity"/>.
+/// </summary>
+/// <typeparam name="TEntity">The type of the entity.</typeparam>
+public partial interface IRepository<TEntity>
+	where TEntity : class
+{
+	/// <summary>
+	/// Returns the first element that matches the specification, or <see langword="null"/>.
+	/// </summary>
+	/// <param name="specification">The specification.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>The entity, or <see langword="null"/>.</returns>
+	Task<TEntity?> FirstOrDefaultAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Returns the first projected result that matches the specification, or <see langword="null"/>.
+	/// </summary>
+	/// <typeparam name="TResult">The result type.</typeparam>
+	/// <param name="specification">The specification.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>The projected result, or <see langword="null"/>.</returns>
+	Task<TResult?> FirstOrDefaultAsync<TResult>(ISpecification<TEntity, TResult> specification, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Returns all entities.
+	/// </summary>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>A list of entities.</returns>
+	Task<List<TEntity>> ListAsync(CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Returns entities that match the specification.
+	/// </summary>
+	/// <param name="specification">The specification.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>A list of entities.</returns>
+	Task<List<TEntity>> ListAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Returns projected results that match the specification.
+	/// </summary>
+	/// <typeparam name="TResult">The result type.</typeparam>
+	/// <param name="specification">The specification.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>A list of projected results.</returns>
+	Task<List<TResult>> ListAsync<TResult>(ISpecification<TEntity, TResult> specification, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Returns the number of entities that match the specification.
+	/// </summary>
+	/// <param name="specification">The specification.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>The count.</returns>
+	Task<int> CountAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Returns the total number of entities.
+	/// </summary>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>The count.</returns>
+	Task<int> CountAsync(CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Returns whether any entity matches the specification.
+	/// </summary>
+	/// <param name="specification">The specification.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns><see langword="true"/> if any entity matches; otherwise <see langword="false"/>.</returns>
+	Task<bool> AnyAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Returns whether any entity exists.
+	/// </summary>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns><see langword="true"/> if any entity exists; otherwise <see langword="false"/>.</returns>
+	Task<bool> AnyAsync(CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Returns an async enumerable for entities that match the specification.
+	/// </summary>
+	/// <param name="specification">The specification.</param>
+	/// <returns>An async enumerable of entities.</returns>
+	IAsyncEnumerable<TEntity> AsAsyncEnumerable(ISpecification<TEntity> specification);
+}
+
+/// <summary>
+/// Defines persistence operations for entities of type <typeparamref name="TEntity"/>.
+/// </summary>
+/// <typeparam name="TEntity">The type of the entity.</typeparam>
+public partial interface IRepository<TEntity>
+{
+	/// <summary>
+	/// Adds an entity.
+	/// </summary>
+	/// <param name="entity">The entity to add.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>The added entity.</returns>
+	Task AddAsync(TEntity entity, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Adds multiple entities.
+	/// </summary>
+	/// <param name="entities">The entities to add.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>The added entities.</returns>
+	Task AddRangeAsync(IEnumerable<TEntity> entities, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Updates an entity.
+	/// </summary>
+	/// <param name="entity">The entity to update.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	Task UpdateAsync(TEntity entity, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Updates multiple entities.
+	/// </summary>
+	/// <param name="entities">The entities to update.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	Task UpdateRangeAsync(IEnumerable<TEntity> entities, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Deletes an entity.
+	/// </summary>
+	/// <param name="entity">The entity to delete.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	Task DeleteAsync(TEntity entity, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Deletes multiple entities.
+	/// </summary>
+	/// <param name="entities">The entities to delete.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	Task DeleteRangeAsync(IEnumerable<TEntity> entities, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Deletes entities that match the specification.
+	/// </summary>
+	/// <param name="specification">The specification.</param>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	Task DeleteRangeAsync(ISpecification<TEntity> specification, CancellationToken cancellationToken = default);
+
+	/// <summary>
+	/// Persists all pending changes.
+	/// </summary>
+	/// <param name="cancellationToken">A cancellation token.</param>
+	/// <returns>The number of affected rows.</returns>
+	Task<int> SaveChangesAsync(CancellationToken cancellationToken = default);
+}

src/request.persistence/ISpecification.cs

@@ -0,0 +1,71 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Encapsulates query logic for <typeparamref name="TEntity"/>.
+/// </summary>
+/// <typeparam name="TEntity">The type being queried against.</typeparam>
+public interface ISpecification<TEntity>
+{
+	/// <summary>
+	/// Gets the collection of filters.
+	/// </summary>
+	IReadOnlyList<WhereExpressionInfo<TEntity>> WhereExpressions { get; }
+
+	/// <summary>
+	/// Gets the collection of order expressions.
+	/// </summary>
+	IReadOnlyList<OrderExpressionInfo<TEntity>> OrderExpressions { get; }
+
+	/// <summary>
+	/// Gets the collection of include expressions.
+	/// </summary>
+	IReadOnlyList<IncludeExpressionInfo> IncludeExpressions { get; }
+
+	/// <summary>
+	/// Gets the collection of search criteria.
+	/// </summary>
+	IReadOnlyList<SearchExpressionInfo<TEntity>> SearchCriteria { get; }
+
+	/// <summary>
+	/// Gets the post-processing action to apply to the result.
+	/// </summary>
+	Func<IEnumerable<TEntity>, IEnumerable<TEntity>>? PostProcessingAction { get; }
+
+	/// <summary>
+	/// Gets the number of elements to take.
+	/// </summary>
+	int? Take { get; }
+
+	/// <summary>
+	/// Gets the number of elements to skip.
+	/// </summary>
+	int? Skip { get; }
+}
+
+/// <summary>
+/// Encapsulates query logic for <typeparamref name="T"/> and projects the result into <typeparamref name="TResult"/>.
+/// </summary>
+/// <typeparam name="T">The type being queried against.</typeparam>
+/// <typeparam name="TResult">The type of the result.</typeparam>
+public interface ISpecification<T, TResult> : ISpecification<T>
+{
+	/// <summary>
+	/// Gets the selector expression.
+	/// </summary>
+	Expression<Func<T, TResult>>? Selector { get; }
+
+	/// <summary>
+	/// Gets the selector many expression.
+	/// </summary>
+	Expression<Func<T, IEnumerable<TResult>>>? SelectorMany { get; }
+
+	/// <summary>
+	/// Gets the post-processing action to apply to the projected result.
+	/// </summary>
+	new Func<IEnumerable<TResult>, IEnumerable<TResult>>? PostProcessingAction { get; }
+}

src/request.persistence/IncludeType.cs

@@ -0,0 +1,20 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Specifies the type of include operation.
+/// </summary>
+public enum IncludeType
+{
+	/// <summary>
+	/// Represents an Include operation.
+	/// </summary>
+	Include = 1,
+
+	/// <summary>
+	/// Represents a ThenInclude operation.
+	/// </summary>
+	ThenInclude = 2,
+}

src/request.persistence/OrderType.cs

@@ -0,0 +1,30 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Specifies the ordering direction.
+/// </summary>
+public enum OrderType
+{
+	/// <summary>
+	/// Orders by ascending.
+	/// </summary>
+	OrderBy = 1,
+
+	/// <summary>
+	/// Orders by descending.
+	/// </summary>
+	OrderByDescending = 2,
+
+	/// <summary>
+	/// Then by ascending.
+	/// </summary>
+	ThenBy = 3,
+
+	/// <summary>
+	/// Then by descending.
+	/// </summary>
+	ThenByDescending = 4
+}

src/request.persistence/Specification.cs

@@ -0,0 +1,103 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Represents a specification for filtering, ordering, and including related entities.
+/// </summary>
+/// <typeparam name="T">The entity type.</typeparam>
+public abstract class Specification<T> : ISpecification<T>
+{
+	/// <summary>
+	/// Creates a new specification.
+	/// </summary>
+	protected Specification()
+		: this(new SpecificationBuilder<T>())
+	{
+	}
+
+	/// <summary>
+	/// Creates a new specification with the given builder.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	protected Specification(SpecificationBuilder<T> builder)
+	{
+		Query = builder;
+	}
+
+	/// <summary>
+	/// Gets the specification builder.
+	/// </summary>
+	protected SpecificationBuilder<T> Query { get; }
+
+	/// <inheritdoc />
+	IReadOnlyList<WhereExpressionInfo<T>> ISpecification<T>.WhereExpressions
+		=> Query.WhereExpressions;
+
+	/// <inheritdoc />
+	IReadOnlyList<OrderExpressionInfo<T>> ISpecification<T>.OrderExpressions
+		=> Query.OrderExpressions;
+
+	/// <inheritdoc />
+	IReadOnlyList<IncludeExpressionInfo> ISpecification<T>.IncludeExpressions
+		=> Query.IncludeExpressions;
+
+	/// <inheritdoc />
+	IReadOnlyList<SearchExpressionInfo<T>> ISpecification<T>.SearchCriteria
+		=> Query.SearchCriteria;
+
+	/// <inheritdoc />
+	Func<IEnumerable<T>, IEnumerable<T>>? ISpecification<T>.PostProcessingAction
+		=> Query.PostProcessingAction;
+
+	/// <inheritdoc />
+	int? ISpecification<T>.Take => Query.Take;
+
+	/// <inheritdoc />
+	int? ISpecification<T>.Skip => Query.Skip;
+}
+
+/// <summary>
+/// Represents a specification for filtering, ordering, and including related entities,
+/// with a projection to <typeparamref name="TResult"/>.
+/// </summary>
+/// <typeparam name="T">The entity type.</typeparam>
+/// <typeparam name="TResult">The result type.</typeparam>
+public abstract class Specification<T, TResult> : Specification<T>, ISpecification<T, TResult>
+{
+	/// <summary>
+	/// Creates a new specification.
+	/// </summary>
+	protected Specification() : this(new SpecificationBuilder<T, TResult>())
+	{
+	}
+
+	/// <summary>
+	/// Creates a new specification with the given builder.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	protected Specification(SpecificationBuilder<T, TResult> builder) : base(builder)
+	{
+		Query = builder;
+	}
+
+	/// <summary>
+	/// Gets the specification builder.
+	/// </summary>
+	protected new SpecificationBuilder<T, TResult> Query { get; }
+
+	/// <inheritdoc />
+	Expression<Func<T, TResult>>? ISpecification<T, TResult>.Selector
+		=> Query.Selector;
+
+	/// <inheritdoc />
+	Expression<Func<T, IEnumerable<TResult>>>? ISpecification<T, TResult>.SelectorMany
+		=> Query.SelectorMany;
+
+	/// <inheritdoc />
+	Func<IEnumerable<TResult>, IEnumerable<TResult>>? ISpecification<T, TResult>.PostProcessingAction
+		=> Query.PostProcessingAction;
+}

src/request.persistence/_builders/IncludableBuilderExtensions.cs

@@ -0,0 +1,101 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Provides extension methods for <see cref="IncludableSpecificationBuilder{T, TProperty}"/>.
+/// </summary>
+public static class IncludableBuilderExtensions
+{
+	/// <summary>
+	/// Specifies a ThenInclude operation on a reference navigation property.
+	/// </summary>
+	/// <param name="builder">The includable builder.</param>
+	/// <param name="expression">The expression.</param>
+	/// <typeparam name="TEntity">The entity type.</typeparam>
+	/// <typeparam name="TPreviousProperty">The previous property type.</typeparam>
+	/// <typeparam name="TProperty">The property type.</typeparam>
+	/// <returns>An includable builder for further chaining.</returns>
+	public static IncludableSpecificationBuilder<TEntity, TProperty> ThenInclude<TEntity, TPreviousProperty, TProperty>(
+		this IncludableSpecificationBuilder<TEntity, TPreviousProperty> builder,
+		Expression<Func<TPreviousProperty, TProperty>> expression)
+		where TEntity : class
+	{
+		return ThenInclude(builder, expression, condition: true);
+	}
+
+	/// <summary>
+	/// Specifies a ThenInclude operation when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The includable builder.</param>
+	/// <param name="expression">The expression.</param>
+	/// <param name="condition">Whether to apply the ThenInclude.</param>
+	/// <typeparam name="TEntity">The entity type.</typeparam>
+	/// <typeparam name="TPreviousProperty">The previous property type.</typeparam>
+	/// <typeparam name="TProperty">The property type.</typeparam>
+	/// <returns>An includable builder for further chaining.</returns>
+	public static IncludableSpecificationBuilder<TEntity, TProperty> ThenInclude<TEntity, TPreviousProperty, TProperty>(
+		this IncludableSpecificationBuilder<TEntity, TPreviousProperty> builder,
+		Expression<Func<TPreviousProperty, TProperty>> expression, bool condition)
+		where TEntity : class
+	{
+		if (condition && !builder.IsChainDiscarded)
+		{
+			var info = new IncludeExpressionInfo(expression, typeof(TEntity), typeof(TProperty), typeof(TPreviousProperty));
+
+			builder.Builder.IncludeExpressions.Add(info);
+		}
+
+		var includeBuilder = new IncludableSpecificationBuilder<TEntity, TProperty>(builder.Builder, !condition || builder.IsChainDiscarded);
+
+		return includeBuilder;
+	}
+
+	/// <summary>
+	/// Specifies a ThenInclude operation on a collection navigation property.
+	/// </summary>
+	/// <param name="previousBuilder">The includable builder.</param>
+	/// <param name="expression">The expression.</param>
+	/// <typeparam name="TEntity">The entity type.</typeparam>
+	/// <typeparam name="TPreviousProperty">The previous property type.</typeparam>
+	/// <typeparam name="TProperty">The property type.</typeparam>
+	/// <returns>An includable builder for further chaining.</returns>
+	public static IncludableSpecificationBuilder<TEntity, TProperty> ThenInclude<TEntity, TPreviousProperty, TProperty>(
+		this IncludableSpecificationBuilder<TEntity, IEnumerable<TPreviousProperty>> previousBuilder,
+		Expression<Func<TPreviousProperty, TProperty>> expression)
+		where TEntity : class
+	{
+		return ThenInclude(previousBuilder, expression, condition: true);
+	}
+
+	/// <summary>
+	/// Specifies a ThenInclude operation on a collection navigation property when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The includable builder.</param>
+	/// <param name="expression">The expression.</param>
+	/// <param name="condition">Whether to apply the ThenInclude.</param>
+	/// <typeparam name="TEntity">The entity type.</typeparam>
+	/// <typeparam name="TPreviousProperty">The previous property type.</typeparam>
+	/// <typeparam name="TProperty">The property type.</typeparam>
+	/// <returns>An includable builder for further chaining.</returns>
+	public static IncludableSpecificationBuilder<TEntity, TProperty> ThenInclude<TEntity, TPreviousProperty, TProperty>(
+		this IncludableSpecificationBuilder<TEntity, IEnumerable<TPreviousProperty>> builder,
+		Expression<Func<TPreviousProperty, TProperty>> expression,
+		bool condition)
+		where TEntity : class
+	{
+		if (condition && !builder.IsChainDiscarded)
+		{
+			var info = new IncludeExpressionInfo(expression, typeof(TEntity), typeof(TProperty), typeof(IEnumerable<TPreviousProperty>));
+
+			builder.Builder.IncludeExpressions.Add(info);
+		}
+
+		var includeBuilder = new IncludableSpecificationBuilder<TEntity, TProperty>(builder.Builder, !condition || builder.IsChainDiscarded);
+
+		return includeBuilder;
+	}
+}

src/request.persistence/_builders/IncludableSpecificationBuilder.cs

@@ -0,0 +1,33 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Provides a builder for chaining ThenInclude operations.
+/// </summary>
+/// <typeparam name="T">The entity type.</typeparam>
+/// <typeparam name="TProperty">The property type.</typeparam>
+public class IncludableSpecificationBuilder<T, TProperty> where T : class
+{
+	/// <summary>
+	/// Gets the underlying specification builder.
+	/// </summary>
+	public SpecificationBuilder<T> Builder { get; }
+
+	/// <summary>
+	/// Gets or sets whether the chain is discarded.
+	/// </summary>
+	public bool IsChainDiscarded { get; set; }
+
+	/// <summary>
+	/// Creates a new includable specification builder.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="isChainDiscarded">Whether the chain is discarded.</param>
+	public IncludableSpecificationBuilder(SpecificationBuilder<T> builder, bool isChainDiscarded = false)
+	{
+		Builder = builder;
+		IsChainDiscarded = isChainDiscarded;
+	}
+}

src/request.persistence/_builders/OrderedBuilderExtensions.cs

@@ -0,0 +1,80 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Provides extension methods for <see cref="OrderedSpecificationBuilder{T}"/>.
+/// </summary>
+public static class OrderedBuilderExtensions
+{
+	/// <summary>
+	/// Adds a ThenBy expression for secondary ordering.
+	/// </summary>
+	/// <param name="builder">The ordered builder.</param>
+	/// <param name="expression">The expression.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The ordered builder.</returns>
+	public static OrderedSpecificationBuilder<T> ThenBy<T>(this OrderedSpecificationBuilder<T> builder, Expression<Func<T, object?>> expression)
+	{
+		return ThenBy(builder, expression, condition: true);
+	}
+
+	/// <summary>
+	/// Adds a ThenBy expression when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The ordered builder.</param>
+	/// <param name="expression">The expression.</param>
+	/// <param name="condition">Whether to apply the ThenBy.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The ordered builder.</returns>
+	public static OrderedSpecificationBuilder<T> ThenBy<T>(this OrderedSpecificationBuilder<T> builder, Expression<Func<T, object?>> expression, bool condition)
+	{
+		if (condition && !builder.IsChainDiscarded)
+		{
+			builder.Builder.OrderExpressions.Add(new OrderExpressionInfo<T>(expression, OrderType.ThenBy));
+		}
+		else
+		{
+			builder.IsChainDiscarded = true;
+		}
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Adds a ThenByDescending expression for secondary ordering.
+	/// </summary>
+	/// <param name="builder">The ordered builder.</param>
+	/// <param name="expression">The expression.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The ordered builder.</returns>
+	public static OrderedSpecificationBuilder<T> ThenByDescending<T>(this OrderedSpecificationBuilder<T> builder, Expression<Func<T, object?>> expression)
+	{
+		return ThenByDescending(builder, expression, condition: true);
+	}
+
+	/// <summary>
+	/// Adds a ThenByDescending expression when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The ordered builder.</param>
+	/// <param name="expression">The expression.</param>
+	/// <param name="condition">Whether to apply the ThenByDescending.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The ordered builder.</returns>
+	public static OrderedSpecificationBuilder<T> ThenByDescending<T>(this OrderedSpecificationBuilder<T> builder, Expression<Func<T, object?>> expression, bool condition)
+	{
+		if (condition && !builder.IsChainDiscarded)
+		{
+			builder.Builder.OrderExpressions.Add(new OrderExpressionInfo<T>(expression, OrderType.ThenByDescending));
+		}
+		else
+		{
+			builder.IsChainDiscarded = true;
+		}
+
+		return builder;
+	}
+}

src/request.persistence/_builders/OrderedSpecificationBuilder.cs

@@ -0,0 +1,32 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Provides a builder for chaining ThenBy / ThenByDescending operations.
+/// </summary>
+/// <typeparam name="T">The entity type.</typeparam>
+public sealed class OrderedSpecificationBuilder<T>
+{
+	/// <summary>
+	/// Gets the underlying specification builder.
+	/// </summary>
+	public SpecificationBuilder<T> Builder { get; }
+
+	/// <summary>
+	/// Gets or sets whether the chain is discarded.
+	/// </summary>
+	public bool IsChainDiscarded { get; set; }
+
+	/// <summary>
+	/// Creates a new ordered specification builder.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="isChainDiscarded">Whether the chain is discarded.</param>
+	public OrderedSpecificationBuilder(SpecificationBuilder<T> builder, bool isChainDiscarded = false)
+	{
+		Builder = builder;
+		IsChainDiscarded = isChainDiscarded;
+	}
+}

src/request.persistence/_builders/SpecificationBuilder.cs

@@ -0,0 +1,72 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Provides a mutable container for building a specification for <typeparamref name="T"/>.
+/// </summary>
+/// <typeparam name="T">The entity type.</typeparam>
+public class SpecificationBuilder<T>
+{
+	/// <summary>
+	/// Gets the list of where expressions.
+	/// </summary>
+	public List<WhereExpressionInfo<T>> WhereExpressions { get; } = [];
+
+	/// <summary>
+	/// Gets the list of order expressions.
+	/// </summary>
+	public List<OrderExpressionInfo<T>> OrderExpressions { get; } = [];
+
+	/// <summary>
+	/// Gets the list of include expressions.
+	/// </summary>
+	public List<IncludeExpressionInfo> IncludeExpressions { get; } = [];
+
+	/// <summary>
+	/// Gets the list of search criteria.
+	/// </summary>
+	public List<SearchExpressionInfo<T>> SearchCriteria { get; } = [];
+
+	/// <summary>
+	/// Gets or sets the post-processing action.
+	/// </summary>
+	public Func<IEnumerable<T>, IEnumerable<T>>? PostProcessingAction { get; set; }
+
+	/// <summary>
+	/// Gets or sets the number of elements to take.
+	/// </summary>
+	public int? Take { get; set; }
+
+	/// <summary>
+	/// Gets or sets the number of elements to skip.
+	/// </summary>
+	public int? Skip { get; set; }
+}
+
+/// <summary>
+/// Provides a mutable container for building a specification for <typeparamref name="T"/>
+/// with a projection to <typeparamref name="TResult"/>.
+/// </summary>
+/// <typeparam name="T">The entity type.</typeparam>
+/// <typeparam name="TResult">The result type.</typeparam>
+public class SpecificationBuilder<T, TResult> : SpecificationBuilder<T>
+{
+	/// <summary>
+	/// Gets or sets the selector expression.
+	/// </summary>
+	public Expression<Func<T, TResult>>? Selector { get; set; }
+
+	/// <summary>
+	/// Gets or sets the selector many expression.
+	/// </summary>
+	public Expression<Func<T, IEnumerable<TResult>>>? SelectorMany { get; set; }
+
+	/// <summary>
+	/// Gets or sets the post-processing action for the projected result.
+	/// </summary>
+	public new Func<IEnumerable<TResult>, IEnumerable<TResult>>? PostProcessingAction { get; set; }
+}

src/request.persistence/_builders/SpecificationBuilderExtensions.cs

@@ -0,0 +1,305 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Provides extension methods for <see cref="SpecificationBuilder{T}"/>.
+/// </summary>
+public static class SpecificationBuilderExtensions
+{
+	/// <summary>
+	/// Adds a filter predicate to the specification.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="criteria">The filter expression.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T> Where<T>(this SpecificationBuilder<T> builder, Expression<Func<T, bool>> criteria)
+	{
+		return Where(builder, criteria, condition: true);
+	}
+
+	/// <summary>
+	/// Adds a filter predicate to the specification when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="criteria">The filter expression.</param>
+	/// <param name="condition">Whether to apply the filter.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T> Where<T>(this SpecificationBuilder<T> builder, Expression<Func<T, bool>> criteria, bool condition)
+	{
+		if (condition)
+		{
+			builder.WhereExpressions.Add(new WhereExpressionInfo<T>(criteria));
+		}
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Adds an ascending order expression.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="orderExpression">The order expression.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>An ordered specification builder for further chaining.</returns>
+	public static OrderedSpecificationBuilder<T> OrderBy<T>(this SpecificationBuilder<T> builder, Expression<Func<T, object?>> orderExpression)
+	{
+		return OrderBy(builder, orderExpression, condition: true);
+	}
+
+	/// <summary>
+	/// Adds an ascending order expression when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="orderExpression">The order expression.</param>
+	/// <param name="condition">Whether to apply the order.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>An ordered specification builder for further chaining.</returns>
+	public static OrderedSpecificationBuilder<T> OrderBy<T>(this SpecificationBuilder<T> builder, Expression<Func<T, object?>> orderExpression, bool condition)
+	{
+		if (condition)
+		{
+			builder.OrderExpressions.Add(new OrderExpressionInfo<T>(orderExpression, OrderType.OrderBy));
+		}
+
+		var orderedSpecificationBuilder = new OrderedSpecificationBuilder<T>(builder, !condition);
+
+		return orderedSpecificationBuilder;
+	}
+
+	/// <summary>
+	/// Adds a descending order expression.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="orderExpression">The order expression.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>An ordered specification builder for further chaining.</returns>
+	public static OrderedSpecificationBuilder<T> OrderByDescending<T>(this SpecificationBuilder<T> builder, Expression<Func<T, object?>> orderExpression)
+	{
+		return OrderByDescending(builder, orderExpression, condition: true);
+	}
+
+	/// <summary>
+	/// Adds a descending order expression when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="orderExpression">The order expression.</param>
+	/// <param name="condition">Whether to apply the order.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>An ordered specification builder for further chaining.</returns>
+	public static OrderedSpecificationBuilder<T> OrderByDescending<T>(this SpecificationBuilder<T> builder, Expression<Func<T, object?>> orderExpression, bool condition)
+	{
+		if (condition)
+		{
+			builder.OrderExpressions.Add(new OrderExpressionInfo<T>(orderExpression, OrderType.OrderByDescending));
+		}
+
+		var orderedSpecificationBuilder = new OrderedSpecificationBuilder<T>(builder, !condition);
+
+		return orderedSpecificationBuilder;
+	}
+
+	/// <summary>
+	/// Adds an include expression to load a related entity.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="includeExpression">The include expression.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <typeparam name="TProperty">The property type.</typeparam>
+	/// <returns>An includable specification builder for further chaining.</returns>
+	public static IncludableSpecificationBuilder<T, TProperty> Include<T, TProperty>(this SpecificationBuilder<T> builder, Expression<Func<T, TProperty>> includeExpression) where T : class
+	{
+		return Include(builder, includeExpression, condition: true);
+	}
+
+	/// <summary>
+	/// Adds an include expression when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="includeExpression">The include expression.</param>
+	/// <param name="condition">Whether to apply the include.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <typeparam name="TProperty">The property type.</typeparam>
+	/// <returns>An includable specification builder for further chaining.</returns>
+	public static IncludableSpecificationBuilder<T, TProperty> Include<T, TProperty>(this SpecificationBuilder<T> builder, Expression<Func<T, TProperty>> includeExpression, bool condition) where T : class
+	{
+		if (condition)
+		{
+			var info = new IncludeExpressionInfo(includeExpression, typeof(T), typeof(TProperty));
+
+			builder.IncludeExpressions.Add(info);
+		}
+
+		var includeBuilder = new IncludableSpecificationBuilder<T, TProperty>(builder, !condition);
+
+		return includeBuilder;
+	}
+
+	/// <summary>
+	/// Specifies the number of elements to return.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="take">The number of elements to take.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T> Take<T>(this SpecificationBuilder<T> builder, int take)
+	{
+		return Take(builder, take, true);
+	}
+
+	/// <summary>
+	/// Specifies the number of elements to return when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="take">The number of elements to take.</param>
+	/// <param name="condition">Whether to apply the take.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T> Take<T>(this SpecificationBuilder<T> builder, int take, bool condition)
+	{
+		if (condition)
+		{
+			if (builder.Take is not null)
+			{
+				throw new DuplicateTakeException();
+			}
+
+			builder.Take = take;
+		}
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Specifies the number of elements to skip before returning.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="skip">The number of elements to skip.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T> Skip<T>(this SpecificationBuilder<T> builder, int skip)
+	{
+		return Skip(builder, skip, condition: true);
+	}
+
+	/// <summary>
+	/// Specifies the number of elements to skip when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="skip">The number of elements to skip.</param>
+	/// <param name="condition">Whether to apply the skip.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T> Skip<T>(this SpecificationBuilder<T> builder, int skip, bool condition)
+	{
+		if (condition)
+		{
+			if (builder.Skip is not null)
+			{
+				throw new DuplicateSkipException();
+			}
+
+			builder.Skip = skip;
+		}
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Specifies a selector to project the result.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="selector">The selector expression.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <typeparam name="TResult">The result type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T, TResult> Select<T, TResult>(this SpecificationBuilder<T, TResult> builder, Expression<Func<T, TResult>> selector)
+	{
+		builder.Selector = selector;
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Specifies a selector many to flatten the result.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="selector">The selector many expression.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <typeparam name="TResult">The result type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T, TResult> SelectMany<T, TResult>(this SpecificationBuilder<T, TResult> builder, Expression<Func<T, IEnumerable<TResult>>> selector)
+	{
+		builder.SelectorMany = selector;
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Specifies a post-processing action to apply to the result.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="predicate">The post-processing action.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T> PostProcessing<T>(this SpecificationBuilder<T> builder, Func<IEnumerable<T>, IEnumerable<T>> predicate)
+	{
+		builder.PostProcessingAction = predicate;
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Specifies a post-processing action to apply to the projected result.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="predicate">The post-processing action.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <typeparam name="TResult">The result type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T, TResult> PostProcessing<T, TResult>(this SpecificationBuilder<T, TResult> builder, Func<IEnumerable<TResult>, IEnumerable<TResult>> predicate)
+	{
+		builder.PostProcessingAction = predicate;
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Adds a search criteria (SQL LIKE) for the given selector.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="selector">The selector expression.</param>
+	/// <param name="searchTerm">The search term.</param>
+	/// <param name="searchGroup">The search group.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T> Search<T>(this SpecificationBuilder<T> builder, Expression<Func<T, string>> selector, string searchTerm, int searchGroup = 1) where T : class
+	{
+		return Search(builder, selector, searchTerm, condition: true, searchGroup);
+	}
+
+	/// <summary>
+	/// Adds a search criteria when <paramref name="condition"/> is <see langword="true"/>.
+	/// </summary>
+	/// <param name="builder">The specification builder.</param>
+	/// <param name="selector">The selector expression.</param>
+	/// <param name="searchTerm">The search term.</param>
+	/// <param name="condition">Whether to apply the search.</param>
+	/// <param name="searchGroup">The search group.</param>
+	/// <typeparam name="T">The entity type.</typeparam>
+	/// <returns>The builder.</returns>
+	public static SpecificationBuilder<T> Search<T>(this SpecificationBuilder<T> builder, Expression<Func<T, string>> selector, string searchTerm, bool condition, int searchGroup = 1) where T : class
+	{
+		if (condition)
+		{
+			builder.SearchCriteria.Add(new SearchExpressionInfo<T>(selector, searchTerm, searchGroup));
+		}
+
+		return builder;
+	}
+}

src/request.persistence/_exceptions/DuplicateSkipException.cs

@@ -0,0 +1,29 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Thrown when <c>Skip</c> is used more than once in the same specification.
+/// </summary>
+public sealed class DuplicateSkipException : Exception
+{
+	private const string ExceptionMessage = "Duplicate use of Skip(). Ensure you don't use Skip() more than once in the same specification!";
+
+	/// <summary>
+	/// Creates a new <see cref="DuplicateSkipException"/>.
+	/// </summary>
+	public DuplicateSkipException()
+		: base(ExceptionMessage)
+	{
+	}
+
+	/// <summary>
+	/// Creates a new <see cref="DuplicateSkipException"/> with an inner exception.
+	/// </summary>
+	/// <param name="innerException">The inner exception.</param>
+	public DuplicateSkipException(Exception innerException)
+		: base(ExceptionMessage, innerException)
+	{
+	}
+}

src/request.persistence/_exceptions/DuplicateTakeException.cs

@@ -0,0 +1,29 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Thrown when <c>Take</c> is used more than once in the same specification.
+/// </summary>
+public sealed class DuplicateTakeException : Exception
+{
+	private const string ExceptionMessage = "Duplicate use of Take(). Ensure you don't use Take() more than once in the same specification!";
+
+	/// <summary>
+	/// Creates a new <see cref="DuplicateTakeException"/>.
+	/// </summary>
+	public DuplicateTakeException()
+		: base(ExceptionMessage)
+	{
+	}
+
+	/// <summary>
+	/// Creates a new <see cref="DuplicateTakeException"/> with an inner exception.
+	/// </summary>
+	/// <param name="innerException">The inner exception.</param>
+	public DuplicateTakeException(Exception innerException)
+		: base(ExceptionMessage, innerException)
+	{
+	}
+}

src/request.persistence/_expressions/IncludeExpressionInfo.cs

@@ -0,0 +1,74 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Stores information about an include expression.
+/// </summary>
+public sealed class IncludeExpressionInfo
+{
+	/// <summary>
+	/// Gets the lambda expression.
+	/// </summary>
+	public LambdaExpression LambdaExpression { get; }
+
+	/// <summary>
+	/// Gets the entity type.
+	/// </summary>
+	public Type EntityType { get; }
+
+	/// <summary>
+	/// Gets the property type.
+	/// </summary>
+	public Type PropertyType { get; }
+
+	/// <summary>
+	/// Gets the previous property type, or <see langword="null"/> for an Include.
+	/// </summary>
+	public Type? PreviousPropertyType { get; }
+
+	/// <summary>
+	/// Gets the include type.
+	/// </summary>
+	public IncludeType Type { get; }
+
+	private IncludeExpressionInfo(LambdaExpression expression, Type entityType, Type propertyType, Type? previousPropertyType, IncludeType includeType)
+	{
+		ArgumentNullException.ThrowIfNull(expression);
+		ArgumentNullException.ThrowIfNull(entityType);
+		ArgumentNullException.ThrowIfNull(propertyType);
+
+		LambdaExpression = expression;
+		EntityType = entityType;
+		PropertyType = propertyType;
+		PreviousPropertyType = previousPropertyType;
+		Type = includeType;
+	}
+
+	/// <summary>
+	/// Creates an Include expression info.
+	/// </summary>
+	/// <param name="expression">The lambda expression.</param>
+	/// <param name="entityType">The entity type.</param>
+	/// <param name="propertyType">The property type.</param>
+	public IncludeExpressionInfo(LambdaExpression expression, Type entityType, Type propertyType)
+		: this(expression, entityType, propertyType, null, IncludeType.Include)
+	{
+	}
+
+	/// <summary>
+	/// Creates a ThenInclude expression info.
+	/// </summary>
+	/// <param name="expression">The lambda expression.</param>
+	/// <param name="entityType">The entity type.</param>
+	/// <param name="propertyType">The property type.</param>
+	/// <param name="previousPropertyType">The previous property type.</param>
+	public IncludeExpressionInfo(LambdaExpression expression, Type entityType, Type propertyType, Type previousPropertyType)
+		: this(expression, entityType, propertyType, previousPropertyType, IncludeType.ThenInclude)
+	{
+		ArgumentNullException.ThrowIfNull(previousPropertyType);
+	}
+}

src/request.persistence/_expressions/OrderExpressionInfo.cs

@@ -0,0 +1,45 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Stores information about an order expression.
+/// </summary>
+/// <typeparam name="T">The entity type.</typeparam>
+public sealed class OrderExpressionInfo<T>
+{
+	private readonly Lazy<Func<T, object?>> _keySelectorFunc;
+
+	/// <summary>
+	/// Creates a new order expression info.
+	/// </summary>
+	/// <param name="keySelector">The key selector expression.</param>
+	/// <param name="orderType">The order type.</param>
+	public OrderExpressionInfo(Expression<Func<T, object?>> keySelector, OrderType orderType)
+	{
+		ArgumentNullException.ThrowIfNull(keySelector);
+
+		KeySelector = keySelector;
+		OrderType = orderType;
+
+		_keySelectorFunc = new Lazy<Func<T, object?>>(KeySelector.Compile);
+	}
+
+	/// <summary>
+	/// Gets the key selector expression.
+	/// </summary>
+	public Expression<Func<T, object?>> KeySelector { get; }
+
+	/// <summary>
+	/// Gets the order type.
+	/// </summary>
+	public OrderType OrderType { get; }
+
+	/// <summary>
+	/// Gets the compiled key selector function.
+	/// </summary>
+	public Func<T, object?> KeySelectorFunc => _keySelectorFunc.Value;
+}

src/request.persistence/_expressions/SearchExpressionInfo.cs

@@ -0,0 +1,53 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Stores information about a search expression.
+/// </summary>
+/// <typeparam name="T">The entity type.</typeparam>
+public sealed class SearchExpressionInfo<T>
+{
+	private readonly Lazy<Func<T, string>> _selectorFunc;
+
+	/// <summary>
+	/// Creates a new search expression info.
+	/// </summary>
+	/// <param name="selector">The selector expression.</param>
+	/// <param name="searchTerm">The search term.</param>
+	/// <param name="searchGroup">The search group.</param>
+	public SearchExpressionInfo(Expression<Func<T, string>> selector, string searchTerm, int searchGroup = 1)
+	{
+		ArgumentNullException.ThrowIfNull(selector);
+		ArgumentException.ThrowIfNullOrEmpty(searchTerm);
+
+		Selector = selector;
+		SearchTerm = searchTerm;
+		SearchGroup = searchGroup;
+
+		_selectorFunc = new Lazy<Func<T, string>>(Selector.Compile);
+	}
+
+	/// <summary>
+	/// Gets the selector expression.
+	/// </summary>
+	public Expression<Func<T, string>> Selector { get; }
+
+	/// <summary>
+	/// Gets the search term.
+	/// </summary>
+	public string SearchTerm { get; }
+
+	/// <summary>
+	/// Gets the search group.
+	/// </summary>
+	public int SearchGroup { get; }
+
+	/// <summary>
+	/// Gets the compiled selector function.
+	/// </summary>
+	public Func<T, string> SelectorFunc => _selectorFunc.Value;
+}

src/request.persistence/_expressions/WhereExpressionInfo.cs

@@ -0,0 +1,38 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Linq.Expressions;
+
+namespace Geekeey.Request.Persistence;
+
+/// <summary>
+/// Stores information about a where expression.
+/// </summary>
+/// <typeparam name="T">The entity type.</typeparam>
+public sealed class WhereExpressionInfo<T>
+{
+	private readonly Lazy<Func<T, bool>> _filterFunc;
+
+	/// <summary>
+	/// Creates a new where expression info.
+	/// </summary>
+	/// <param name="filter">The filter expression.</param>
+	public WhereExpressionInfo(Expression<Func<T, bool>> filter)
+	{
+		ArgumentNullException.ThrowIfNull(filter);
+
+		Filter = filter;
+
+		_filterFunc = new Lazy<Func<T, bool>>(Filter.Compile);
+	}
+
+	/// <summary>
+	/// Gets the filter expression.
+	/// </summary>
+	public Expression<Func<T, bool>> Filter { get; }
+
+	/// <summary>
+	/// Gets the compiled filter function.
+	/// </summary>
+	public Func<T, bool> FilterFunc => _filterFunc.Value;
+}

src/request.result.tests/ResultEqualityTests.cs

@@ -166,48 +166,11 @@ internal sealed class ResultEqualityTests
 	}
 
 	[Test]
-	public async Task I_can_get_hashcode_and_get_non_zero_for_failure()
+	public async Task I_can_get_hashcode_and_get_zero_for_failure()
 	{
 		var result = Prelude.Failure<int>("error");
 
-		await Assert.That(result.GetHashCode()).IsNotEqualTo(0);
-	}
-
-	[Test]
-	public async Task I_can_get_hashcode_and_not_collide_non_generic_success_and_failure()
-	{
-		await Assert.That(Prelude.Success().GetHashCode())
-			.IsNotEqualTo(Prelude.Failure("error").GetHashCode());
-	}
-
-	[Test]
-	public async Task I_can_get_hashcode_and_not_collide_success_value_zero_with_failure()
-	{
-		var success = Prelude.Success(0);
-		var failure = Prelude.Failure<int>("error");
-
-		await Assert.That(success.Equals(failure)).IsFalse();
-		await Assert.That(success.GetHashCode()).IsNotEqualTo(failure.GetHashCode());
-	}
-
-	[Test]
-	public async Task I_can_equal_failure_and_failure_ignoring_error_content()
-	{
-		var a = Prelude.Failure<int>("error 1");
-		var b = Prelude.Failure<int>("error 2");
-
-		await Assert.That(a.Equals(b)).IsTrue();
-		await Assert.That(a.Error).IsNotEqualTo(b.Error);
-	}
-
-	[Test]
-	public async Task I_can_equal_non_generic_failure_and_failure_ignoring_error_content()
-	{
-		var a = Prelude.Failure("error 1");
-		var b = Prelude.Failure("error 2");
-
-		await Assert.That(a.Equals(b)).IsTrue();
-		await Assert.That(a.Error).IsNotEqualTo(b.Error);
+		await Assert.That(result.GetHashCode()).IsZero();
 	}
 
 	[Test]
@@ -236,53 +199,4 @@ internal sealed class ResultEqualityTests
 
 		await Assert.That(a.Equals(b)).IsFalse();
 	}
-
-	[Test]
-	public async Task I_can_use_equality_operator_and_get_false_for_success_and_failure()
-	{
-		var success = Prelude.Success(2);
-		var failure = Prelude.Failure<int>("error");
-
-		await Assert.That(success == failure).IsFalse();
-		await Assert.That(success != failure).IsTrue();
-	}
-
-	[Test]
-	public async Task I_can_use_equality_operator_and_get_true_for_successes_with_equal_value()
-	{
-		await Assert.That(Prelude.Success(2) == Prelude.Success(2)).IsTrue();
-		await Assert.That(Prelude.Success(2) != Prelude.Success(3)).IsTrue();
-	}
-
-	[Test]
-	public async Task I_can_use_equality_operator_and_compare_result_to_value()
-	{
-		await Assert.That(Prelude.Success(2) == 2).IsTrue();
-		await Assert.That(Prelude.Success(2) != 3).IsTrue();
-		await Assert.That(Prelude.Failure<int>("x") == 2).IsFalse();
-	}
-
-	[Test]
-	public async Task I_can_equal_object_and_get_false_for_null()
-	{
-		object result = Prelude.Success(2);
-
-		await Assert.That(result.Equals(null)).IsFalse();
-	}
-
-	[Test]
-	public async Task I_can_equal_object_and_get_false_for_wrong_type()
-	{
-		object result = Prelude.Success(2);
-
-		await Assert.That(result.Equals("not a result")).IsFalse();
-	}
-
-	[Test]
-	public async Task I_can_equal_object_and_get_true_for_boxed_equal_result()
-	{
-		object result = Prelude.Success(2);
-
-		await Assert.That(result.Equals(Prelude.Success(2))).IsTrue();
-	}
 }

src/request.result/Prelude.cs

@@ -9,7 +9,7 @@ namespace Geekeey.Request.Result;
 /// A class containing various utility methods, a 'prelude' to the rest of the library.
 /// </summary>
 /// <remarks>
-/// This class is meant to be imported statically, e.g. <c>using static Geekeey.Request.Result.Prelude;</c>.
+/// This class is meant to be imported statically, e.g. <c>using static Geekeey.Extensions.Result.Prelude;</c>.
 /// Recommended to be imported globally via a global using statement.
 /// </remarks>
 public static class Prelude

src/request.result/Result.Equality.cs

@@ -9,15 +9,7 @@ namespace Geekeey.Request.Result;
 
 public partial class Result : IEquatable<Result>
 {
-	/// <summary>
-	/// Checks whether two results are equal. Results are equal if both are success or both are failure.
-	/// </summary>
-	/// <remarks>
-	/// Two failures are considered equal regardless of their <see cref="Error"/> content. Equality therefore
-	/// ignores the error; if you need to branch on a specific failure, compare the <see cref="Error"/> values
-	/// directly instead of relying on equality.
-	/// </remarks>
-	/// <param name="other">The result to check for equality with the current result.</param>
+	/// <inheritdoc/>
 	[Pure]
 	public bool Equals(Result? other)
 	{
@@ -57,8 +49,7 @@ public partial class Result : IEquatable<Result>
 public partial class Result : IEqualityOperators<Result, Result, bool>
 {
 	/// <summary>
-	/// Checks whether two results are equal. Results are equal if they are both success or both failure. Two
-	/// failures are equal regardless of their error content.
+	/// Checks whether two results are equal. Results are equal if they are both success or both failure.
 	/// </summary>
 	/// <param name="a">The first result to compare.</param>
 	/// <param name="b">The second result to compare.</param>
@@ -88,11 +79,6 @@ public partial class Result<T> : IEquatable<Result<T>>, IEquatable<T>
 	/// Checks whether the result is equal to another result. Results are equal if both results are success values and
 	/// the success values are equal, or if both results are failures.
 	/// </summary>
-	/// <remarks>
-	/// Two failures are considered equal regardless of their <see cref="Error"/> content. Equality therefore
-	/// ignores the error; if you need to branch on a specific failure, compare the <see cref="Error"/> values
-	/// directly instead of relying on equality.
-	/// </remarks>
 	/// <param name="other">The result to check for equality with the current result.</param>
 	[Pure]
 	public bool Equals(Result<T>? other)
@@ -195,20 +181,15 @@ public partial class Result<T> : IEquatable<Result<T>>, IEquatable<T>
 			return comparer.GetHashCode(result.Value);
 		}
 
-		if (result is { IsSuccess: true, Value: null })
-		{
 		return 0;
 	}
-
-		return result.Error?.GetHashCode() ?? 0;
-	}
 }
 
 public partial class Result<T> : IEqualityOperators<Result<T>, Result<T>, bool>, IEqualityOperators<Result<T>, T, bool>
 {
 	/// <summary>
 	/// Checks whether two results are equal. Results are equal if both results are success values and the success
-	/// values are equal, or if both results are failures. Two failures are equal regardless of their error content.
+	/// values are equal, or if both results are failures.
 	/// </summary>
 	/// <param name="a">The first result to compare.</param>
 	/// <param name="b">The second result to compare.</param>

src/request.validation.tests/RuleBuilderExtensionsTests.cs

@@ -314,71 +314,6 @@ internal sealed class RuleBuilderExtensionsTests
 			.Throws<ArgumentOutOfRangeException>();
 	}
 
-	[Test]
-	public async Task I_can_validate_greater_than_with_null_bound_without_throwing()
-	{
-		var validator = new PropertyValidator<ComparableModel, ComparableValue?>(model
-			=> model.Value, rule => rule.GreaterThan(null));
-
-		var valid = validator.Validate(new ComparableModel { Value = new ComparableValue { Number = 1 } });
-		var ignoredNull = validator.Validate(new ComparableModel());
-
-		await Assert.That(valid.IsValid).IsTrue();
-		await Assert.That(ignoredNull.IsValid).IsTrue();
-	}
-
-	[Test]
-	public async Task I_can_validate_greater_than_or_equal_to_with_null_bound_without_throwing()
-	{
-		var validator = new PropertyValidator<ComparableModel, ComparableValue?>(model
-			=> model.Value, rule => rule.GreaterThanOrEqualTo(null));
-
-		var valid = validator.Validate(new ComparableModel { Value = new ComparableValue { Number = 1 } });
-		var ignoredNull = validator.Validate(new ComparableModel());
-
-		await Assert.That(valid.IsValid).IsTrue();
-		await Assert.That(ignoredNull.IsValid).IsTrue();
-	}
-
-	[Test]
-	public async Task I_can_validate_less_than_with_null_bound_without_throwing()
-	{
-		var validator = new PropertyValidator<ComparableModel, ComparableValue?>(model
-			=> model.Value, rule => rule.LessThan(null));
-
-		var valid = validator.Validate(new ComparableModel { Value = new ComparableValue { Number = 1 } });
-		var ignoredNull = validator.Validate(new ComparableModel());
-
-		await Assert.That(valid.IsValid).IsTrue();
-		await Assert.That(ignoredNull.IsValid).IsTrue();
-	}
-
-	[Test]
-	public async Task I_can_validate_less_than_or_equal_to_with_null_bound_without_throwing()
-	{
-		var validator = new PropertyValidator<ComparableModel, ComparableValue?>(model
-			=> model.Value, rule => rule.LessThanOrEqualTo(null));
-
-		var valid = validator.Validate(new ComparableModel { Value = new ComparableValue { Number = 1 } });
-		var ignoredNull = validator.Validate(new ComparableModel());
-
-		await Assert.That(valid.IsValid).IsTrue();
-		await Assert.That(ignoredNull.IsValid).IsTrue();
-	}
-
-	[Test]
-	public async Task I_can_validate_between_with_null_bounds_without_throwing()
-	{
-		var validator = new PropertyValidator<ComparableModel, ComparableValue?>(model
-			=> model.Value, rule => rule.Between(null, null));
-
-		var valid = validator.Validate(new ComparableModel { Value = new ComparableValue { Number = 1 } });
-		var ignoredNull = validator.Validate(new ComparableModel());
-
-		await Assert.That(valid.IsValid).IsTrue();
-		await Assert.That(ignoredNull.IsValid).IsTrue();
-	}
-
 	[Test]
 	public async Task I_can_see_it_throw_for_invalid_between_configuration()
 	{

src/request.validation.tests/ValidationSeverityTests.cs

@@ -1,49 +0,0 @@
-// Copyright (c) The Geekeey Authors
-// SPDX-License-Identifier: EUPL-1.2
-
-namespace Geekeey.Request.Validation.Tests;
-
-internal sealed class ValidationSeverityTests
-{
-	[Test]
-	public async Task I_can_have_warning_problems_not_invalidate_by_default()
-	{
-		var validator = new PropertyValidator<Person, string?>(person
-			=> person.Name, rule => rule.Must(value => !string.IsNullOrWhiteSpace(value), "Name is required.")
-			.WithSeverity(Severity.Warning));
-
-		var result = validator.Validate(new Person { Name = "" });
-
-		await Assert.That(result.Problems).Count().IsEqualTo(1);
-		await Assert.That(result.IsValid).IsTrue();
-		await Assert.That(result.IsValidFor(Severity.Warning)).IsFalse();
-		await Assert.That(result.IsValidFor(Severity.Info)).IsFalse();
-	}
-
-	[Test]
-	public async Task I_can_have_info_problems_only_invalidate_at_info_threshold()
-	{
-		var validator = new PropertyValidator<Person, string?>(person
-			=> person.Name, rule => rule.Must(value => !string.IsNullOrWhiteSpace(value), "Name is required.")
-			.WithSeverity(Severity.Info));
-
-		var result = validator.Validate(new Person { Name = "" });
-
-		await Assert.That(result.Problems).Count().IsEqualTo(1);
-		await Assert.That(result.IsValid).IsTrue();
-		await Assert.That(result.IsValidFor(Severity.Warning)).IsTrue();
-		await Assert.That(result.IsValidFor(Severity.Info)).IsFalse();
-	}
-
-	[Test]
-	public async Task I_can_have_error_problems_invalidate_by_default()
-	{
-		var validator = new PropertyValidator<Person, string?>(person
-			=> person.Name, rule => rule.Must(value => !string.IsNullOrWhiteSpace(value), "Name is required."));
-
-		var result = validator.Validate(new Person { Name = "" });
-
-		await Assert.That(result.IsValid).IsFalse();
-		await Assert.That(result.IsValidFor(Severity.Error)).IsFalse();
-	}
-}

src/request.validation.tests/ValidatorTests.cs

@@ -14,8 +14,7 @@ internal sealed class ValidatorTests
 
 		var result = validator.Validate(new Person { Name = "" });
 
-		await Assert.That(result.IsValid).IsTrue();
-		await Assert.That(result.IsValidFor(Severity.Warning)).IsFalse();
+		await Assert.That(result.IsValid).IsFalse();
 		await Assert.That(result.Problems).Count().IsEqualTo(1);
 
 		var problem = result.Problems.Single();
@@ -40,24 +39,12 @@ internal sealed class ValidatorTests
 
 		using (Assert.Multiple())
 		{
-			await Assert.That(invalid.IsValid).IsTrue();
-			await Assert.That(invalid.IsValidFor(Severity.Warning)).IsFalse();
+			await Assert.That(invalid.IsValid).IsFalse();
 			await Assert.That(valid.IsValid).IsTrue();
 			await Assert.That(valid.Problems).IsEmpty();
 		}
 	}
 
-	[Test]
-	public async Task I_can_validate_with_a_null_instance_without_throwing()
-	{
-		var validator = new PropertyValidator<Person?, string?>(person
-			=> person!.Name, rule => rule.Must(value => value is not null, "Name is required."));
-
-		var result = validator.Validate((Person?)null);
-
-		await Assert.That(result.IsValid).IsTrue();
-	}
-
 	[Test]
 	public async Task I_can_compose_nested_validators_and_aggregate_property_paths()
 	{

src/request.validation.tests/_fixtures/ComparableModel.cs

@@ -1,19 +0,0 @@
-// Copyright (c) The Geekeey Authors
-// SPDX-License-Identifier: EUPL-1.2
-
-namespace Geekeey.Request.Validation.Tests;
-
-internal sealed class ComparableModel
-{
-	public ComparableValue? Value { get; init; }
-}
-
-internal sealed class ComparableValue : IComparable<ComparableValue?>
-{
-	public int Number { get; init; }
-
-	public int CompareTo(ComparableValue? other)
-	{
-		return Number.CompareTo(other!.Number);
-	}
-}

src/request.validation/Rule.cs

@@ -46,7 +46,7 @@ internal abstract record Rule<T, TProperty> : Rule
 
 		if (context.Instance is null && default(T) is null)
 		{
-			return [];
+			return Validate((T)context.Instance!, context);
 		}
 
 		var actualType = context.Instance?.GetType().FullName ?? "null";