From eff887b49f4c9458fa4926e97e16cdee46ae3c71 Mon Sep 17 00:00:00 2001
From: Louis Seubert <louis.seubert.ls@gmail.com>
Date: Sat, 30 May 2026 21:17:14 +0200
Subject: [PATCH] feat: add json property path supports for object keys

---
 CHANGELOG.md                                  |  2 +
 .../PropertyPathTests.cs                      | 39 +++++++++++++++++++
 src/request.validation/PropertyPath.cs        | 17 ++++++++
 3 files changed, 58 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9f1288b..240c251 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -41,6 +41,8 @@ To have a consistent experience across all packages, some public interfaces have
 
 ### Added
 
+- **request.validation:** Support `PropertyPath` JSON converter for string values and dictionary property names
+
 ### Changed
 
 ### Removed
diff --git a/src/request.validation.tests/PropertyPathTests.cs b/src/request.validation.tests/PropertyPathTests.cs
index bce4614..2551450 100644
--- a/src/request.validation.tests/PropertyPathTests.cs
+++ b/src/request.validation.tests/PropertyPathTests.cs
@@ -12,6 +12,19 @@ internal sealed class PropertyPathTests
 		PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
 	};
 
+	private static readonly JsonSerializerOptions CamelCaseDictionaryKeyJsonOptions = new()
+	{
+		DictionaryKeyPolicy = JsonNamingPolicy.CamelCase,
+	};
+
+	[Test]
+	public async Task I_can_serialize_property_paths_as_json_strings_using_the_json_naming_policy()
+	{
+		var json = JsonSerializer.Serialize((PropertyPath)"Address.Street", CamelCaseJsonOptions);
+
+		await Assert.That(json).IsEqualTo(/*lang=json,strict*/ "\"address.street\"");
+	}
+
 	[Test]
 	public async Task I_can_serialize_property_paths_using_the_json_naming_policy()
 	{
@@ -54,6 +67,32 @@ internal sealed class PropertyPathTests
 		await Assert.That(json).IsEqualTo(/*lang=json,strict*/ """{"propertyPath":"matrix[1][2].value","severity":0,"message":"Value is required.","code":null,"attemptedValue":null}""");
 	}
 
+	[Test]
+	public async Task I_can_serialize_property_paths_as_dictionary_keys_using_the_dictionary_key_policy()
+	{
+		Dictionary<PropertyPath, string> errors = new()
+		{
+			["Address.Street"] = "Street is required.",
+		};
+
+		var json = JsonSerializer.Serialize(errors, CamelCaseDictionaryKeyJsonOptions);
+
+		await Assert.That(json).IsEqualTo(/*lang=json,strict*/ """{"address.street":"Street is required."}""");
+	}
+
+	[Test]
+	public async Task I_can_deserialize_property_paths_from_dictionary_keys()
+	{
+		var json = /*lang=json,strict*/ """{"Address.Street":"Street is required."}""";
+
+		var errors = JsonSerializer.Deserialize<Dictionary<PropertyPath, string>>(json);
+
+		await Assert.That(errors).IsNotNull();
+		await Assert.That(errors!.Count).IsEqualTo(1);
+		await Assert.That(errors.ContainsKey("Address.Street")).IsTrue();
+		await Assert.That(errors["Address.Street"]).IsEqualTo("Street is required.");
+	}
+
 	[Test]
 	public async Task I_can_iterate_and_index_segments()
 	{
diff --git a/src/request.validation/PropertyPath.cs b/src/request.validation/PropertyPath.cs
index 4bf0e62..4b9bd50 100644
--- a/src/request.validation/PropertyPath.cs
+++ b/src/request.validation/PropertyPath.cs
@@ -399,9 +399,26 @@ internal sealed class PropertyPathJsonConverter : JsonConverter<PropertyPath>
 		throw new JsonException($"Expected {nameof(JsonTokenType.String)} but got {reader.TokenType}.");
 	}
 
+	/// <inheritdoc />
+	public override PropertyPath ReadAsPropertyName(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+	{
+		if (reader.TokenType is JsonTokenType.PropertyName)
+		{
+			return new PropertyPath(reader.GetString()!);
+		}
+
+		throw new JsonException($"Expected {nameof(JsonTokenType.PropertyName)} but got {reader.TokenType}.");
+	}
+
 	/// <inheritdoc />
 	public override void Write(Utf8JsonWriter writer, PropertyPath value, JsonSerializerOptions options)
 	{
 		writer.WriteStringValue(value.ToJsonName(options.PropertyNamingPolicy));
 	}
+
+	/// <inheritdoc />
+	public override void WriteAsPropertyName(Utf8JsonWriter writer, PropertyPath value, JsonSerializerOptions options)
+	{
+		writer.WritePropertyName(value.ToJsonName(options.DictionaryKeyPolicy));
+	}
 }