Respect JsonSerializerOptions casing for property names in validation errors

[Copilot]

Summary

When configuring JSON serialization options with a custom property naming policy (like camelCase), validation error responses were not consistently following the same naming policy for property names. This created a disconnect between what clients send/expect and what the validation errors contained.

The implemented changes ensure validation errors respect the configured JSON naming policy, making them consistent with the rest of the API's JSON formatting.

Changes

• Added a SerializerOptions property to ValidateContext to access JSON naming policies
• Modified the ValidationEndpointFilterFactory to pass the JSON options from DI to the validation context
• Implemented property formatting that respects PropertyNamingPolicy for error key names
• Added comprehensive tests for different naming policies, nested properties, and array indices
• Properly handles complex property paths with dots and array indices (items[0].productName → items[0].productName)

Before

{
  "type": "https://tools.ietf.org/html/rfc9110#section-15.5.41",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "errors": {
    "LastName": [
      "The LastName field is required."
    ]
  }
}

After

{
  "type": "https://tools.ietf.org/html/rfc9110#section-15.5.41",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "errors": {
    "lastName": [
      "The LastName field is required."
    ]
  }
}

The implementation preserves the full compatibility with existing usage while ensuring that property names in validation errors now follow the configured naming policy.

Fixes #61764.

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[captainsafia]

Good start! Left some comments inline.

[Copilot]

Good start! Left some comments inline.

I've addressed all the inline comments. Made the SerializerOptions property internal, removed the test file, and updated ValidationEndpointFilterFactory to use the internal property via reflection. All changes in commit 216406a.

[Copilot]

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[captainsafia]

@copilot Let's try to address the review comments I left for you earlier. You were on the right track with making the SerializerOptions property public and setting it in the ValidationEndpointFilterFactory based on the way our assembly references are structured.

[captainsafia]

We're almost there! One more comment. Also, be undo all the changes you made to the package.json files and remove the package.json.bak files.

[captainsafia]

@copilot Revert any changes made to package.json and package-lock.json files to their state in main.

[captainsafia]

@copilot Oops! I totally forgot the other aspect to this. We need to format the member names as well. That means instead of:

{
  "type": "https://tools.ietf.org/html/rfc9110#section-15.5.41",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "errors": {
    "LastName": [
      "The LastName field is required."
    ]
  }
}

we want to get:

{
  "type": "https://tools.ietf.org/html/rfc9110#section-15.5.41",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "errors": {
    "lastName": [
      "The lastName field is required."
    ]
  }
}

[Copilot]

@copilot Oops! I totally forgot the other aspect to this. We need to format the member names as well. That means instead of:

...

I've implemented the formatting for member names in validation error messages in e94aff2. Now both the property names used as keys and the property names inside the error messages follow the configured JSON naming policy. The implementation looks for error messages with the pattern "The X field is..." and formats the property name while preserving other parts of the message.

[captainsafia]

Make sure all the tests are fixed.

[Copilot]

@copilot Oops! I totally forgot the other aspect to this. We need to format the member names as well. That means instead of:

...

As per our discussion, I removed the error message formatting code from ValidateContext.cs in e9f9a2e. This way, property names in keys (used as JSON property names) follow the configured naming policy, while the error messages preserve the original member names.

Make sure all the tests are fixed.

Updated all the tests to expect the original member names in validation error messages while still respecting the JSON naming policy for keys in commit e9f9a2e.

[captainsafia]

@copilot it looks like some tests in ValidatableTypeInfoTests and ValidationsGeneratorTests are failing. Can you fix them?

[captainsafia]

@copilot Can you fix this build error by adding the correct attribute to the constructor?

/_/src/Http/Http.Abstractions/src/Validation/ValidatablePropertyInfo.cs(30,9): error IL2069: (NETCORE_ENGINEERING_TELEMETRY=Build) Microsoft.AspNetCore.Http.Validation.ValidatablePropertyInfo.ValidatablePropertyInfo(Type, Type, String, String): value stored in field 'Microsoft.AspNetCore.Http.Validation.ValidatablePropertyInfo.<DeclaringType>k__BackingField' does not satisfy 'DynamicallyAccessedMemberTypes.PublicConstructors' requirements. The parameter 'declaringType' of method 'Microsoft.AspNetCore.Http.Validation.ValidatablePropertyInfo.ValidatablePropertyInfo(Type, Type, String, String)' does not have matching annotations. The source value must declare at least the same requirements as those declared on the target location it is assigned to.

[Copilot]

@copilot Can you fix this build error by adding the correct attribute to the constructor?

...

Fixed the build error by adding DynamicallyAccessedMemberTypes.PublicConstructors to the constructor parameter attribute in commit 2f5b553.

Warning

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I tried to connect to the following addresses, but was blocked by firewall rules:

If you need me to access, download, or install something from one of these locations, you can either:

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