Fix OpenAPI enum schema for non-body parameters with naming policy

[mikekistler]

Summary

Fixes #65026

When a global JsonStringEnumConverter with a naming policy (e.g. KebabCaseLower) is configured via ConfigureHttpJsonOptions, the OpenAPI spec emits naming-policy-transformed enum values (e.g. my-value) for all parameters. However, query/path/header parameter binding uses Enum.TryParse, which only accepts the original C# member names (e.g. MyValue). This causes clients following the spec to send values that the server rejects with 400.

Changes

JsonNodeSchemaExtensions.ApplyParameterInfo — For non-body enum parameters (query, path, header), replaces the naming-policy-transformed enum values with Enum.GetNames() so the schema matches what Enum.TryParse accepts.

OpenApiSchemaService.GetOrCreateSchemaAsync — When a naming policy transforms enum values, skips schema componentization for non-body enum parameters and returns an inline schema instead. This prevents the shared component (which retains naming-policy values for body serialization) from overwriting the corrected parameter schema.

These two changes work together so that:

• Query/path/header params show PascalCase enum values (matching Enum.TryParse behavior)
• Body params/responses keep naming-policy-transformed values (matching JSON serialization)
• Enums with attribute-level converters (no global naming policy) are unaffected

Tests

• GetOpenApiParameters_EnumWithGlobalNamingPolicy_UsesOriginalMemberNames — verifies query param enum values are PascalCase when a global KebabCaseLower policy is configured
• GetOpenApiParameters_EnumWithGlobalNamingPolicy_HandlesQueryAndBodyUsage — verifies the same enum type produces PascalCase for query params and kebab-case for body responses

All 222 OpenApiSchemaServiceTests pass.

[Copilot]

Pull request overview

Fixes an OpenAPI/spec mismatch where global JsonStringEnumConverter naming policies were being applied to non-body parameters (query/path/header), even though runtime binding uses Enum.TryParse and only accepts the original C# enum member names.

Changes:

• Adjust enum parameter schemas for non-body parameters to emit original enum member names.
• Avoid schema componentization for affected non-body enum parameters to prevent shared component schemas (used for body serialization) from overwriting corrected parameter schemas.
• Add tests covering query-parameter enums with a global naming policy, including mixed query + response usage of the same enum.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Shared/SharedTypes.cs	Adds a new test enum (Priority) used for global-naming-policy scenarios.
src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiSchemaService/OpenApiSchemaService.ParameterSchemas.cs	Adds coverage ensuring query parameter enums use original member names while response bodies keep naming-policy output.
src/OpenApi/src/Services/Schemas/OpenApiSchemaService.cs	Skips componentization for affected non-body enum parameters when naming policy transforms enum values.
src/OpenApi/src/Extensions/JsonNodeSchemaExtensions.cs	Rewrites enum values for applicable parameter schemas to match Enum.TryParse expectations.

[Copilot]

The comment and intent here mention form parameters, but IsNonBodyBindingSource excludes BindingSource.Form. As a result, enums coming from form fields (application/x-www-form-urlencoded or multipart) will keep naming-policy-transformed values in the schema even though form binding does not honor JSON enum naming policies. Include BindingSource.Form in IsNonBodyBindingSource (or update the comment if forms are intentionally out of scope).

Suggested change

	|| bindingSource == BindingSource.Path;
	|| bindingSource == BindingSource.Path
	|| bindingSource == BindingSource.Form;

[Copilot]

IsNonBodyBindingSource excludes BindingSource.Form, but form fields are also not JSON-body serialized and their enum parsing won't respect JsonStringEnumConverter naming policies. If forms can contain enums, they can hit the same schema mismatch and also the same componentization collision with body/response schemas. Consider treating BindingSource.Form as non-body here (or otherwise ensuring form enum schemas are corrected and not overwritten by shared components).

Suggested change

	private static bool IsNonBodyBindingSource(BindingSource bindingSource) => bindingSource == BindingSource.Header
	|| bindingSource == BindingSource.Query
	|| bindingSource == BindingSource.Path;
	private static bool IsNonBodyBindingSource(BindingSource bindingSource) => bindingSource switch
	{
	var source when source == BindingSource.Header => true,
	var source when source == BindingSource.Query => true,
	var source when source == BindingSource.Path => true,
	var source when source == BindingSource.Form => true,
	_ => false,
	};