Fix missing OpenAPI 3.1 $ref properties

[martincostello]

Fix missing properties on OpenAPI 3.1 schema references (default, deprecated).

Resolves #3858.

[Copilot]

Pull request overview

This PR addresses issue #3858 by ensuring OpenAPI 3.1 schemas can retain certain “sibling” properties (default, deprecated) even when the schema is emitted as a $ref, improving fidelity for referenced enums and other referenced schemas.

Changes:

• Update SchemaGenerator to emit default/deprecated on OpenAPI 3.1 $ref schemas (when not using allOf wrapping).
• Extend integration test coverage to snapshot OpenAPI 2.0 and 3.1 outputs for the Basic test site.
• Add/adjust fixtures and unit tests to cover enum default values and deprecated properties.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/SchemaGenerator.cs	Adds default/deprecated support on referenced member schemas without forcing allOf.
test/WebSites/Basic/Controllers/SwaggerAnnotationsController.cs	Adds enum default and an obsolete property to exercise $ref + default/deprecated behavior.
test/WebSites/Basic/Controllers/DefaultValuesAttribute.cs	Removes unused custom attribute in favor of System.ComponentModel.DefaultValueAttribute.
test/Swashbuckle.AspNetCore.TestSupport/Fixtures/TypeWithDefaultAttributes.cs	Adds an enum property with DefaultValue for unit test coverage.
test/Swashbuckle.AspNetCore.TestSupport/Fixtures/TypeWithDefaultAttributeOnEnum.cs	Minor formatting update in fixture (no functional change).
test/Swashbuckle.AspNetCore.TestSupport/Fixtures/ComplexType.cs	Adds an enum property with DefaultValue and updates usings for schema-generation tests.
test/Swashbuckle.AspNetCore.SwaggerGen.Test/SchemaGenerator/JsonSerializerSchemaGeneratorTests.cs	Updates schema assertions and adds enum default test coverage.
test/Swashbuckle.AspNetCore.Newtonsoft.Test/SchemaGenerator/NewtonsoftSchemaGeneratorTests.cs	Updates schema assertions to account for the new ComplexType property.
test/Swashbuckle.AspNetCore.IntegrationTests/VerifyTests.cs	Adds snapshot coverage for Basic’s 2.0 and 3.1 endpoints and disambiguates snapshot parameters.
test/Swashbuckle.AspNetCore.IntegrationTests/SwaggerIntegrationTests.cs	Includes the additional Basic endpoints in integration coverage.
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/code/GeneratesValidClient_6548ff89f26311aa/Models/Cart.verified.cs	Snapshot updated for the newly added model property.
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/8_0/VerifyTests.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=v1.verified.txt	Snapshot updated for the added model property.
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/8_0/VerifyTests.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=2.0.verified.txt	New snapshot covering OpenAPI 2.0 output.
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/8_0/VerifyTests.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=3.1.verified.txt	New snapshot covering OpenAPI 3.1 output (incl. $ref sibling props).
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/9_0/VerifyTests.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=v1.verified.txt	Snapshot updated for the added model property.
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/9_0/VerifyTests.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=2.0.verified.txt	New snapshot covering OpenAPI 2.0 output.
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/9_0/VerifyTests.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=3.1.verified.txt	New snapshot covering OpenAPI 3.1 output (incl. $ref sibling props).
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/10_0/VerifyTests.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=v1.verified.txt	Snapshot updated for the added model property.
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/10_0/VerifyTests.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=2.0.verified.txt	New snapshot covering OpenAPI 2.0 output.
test/Swashbuckle.AspNetCore.IntegrationTests/snapshots/10_0/VerifyTests.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=3.1.verified.txt	New snapshot covering OpenAPI 3.1 output (incl. $ref sibling props).

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.97%. Comparing base (ef008b6) to head (135623b).
⚠️ Report is 1 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3859      +/-   ##
==========================================
+ Coverage   94.95%   94.97%   +0.02%     
==========================================
  Files         111      111              
  Lines        3886     3903      +17     
  Branches      783      789       +6     
==========================================
+ Hits         3690     3707      +17     
  Misses        196      196              

Flag	Coverage Δ
Linux	94.97% <100.00%> (+0.02%)	⬆️
Windows	94.97% <100.00%> (+0.02%)	⬆️
macOS	94.97% <100.00%> (+0.02%)	⬆️

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