Upgrade to OpenAPI.NET v2.0.0-preview7

[captainsafia]

Contributes towards #58619.

• Remove nullable keyword from schema and support null as a value in the type property
• Remove type overrides for primitives types in ApplyPrimitiveTypesAndFormats
• Replace .Reference with OpenApiSchemaReference definitions
• Update type signatures to match introduction of interfaces to API

[mikekistler]

Most of this is over my head, but I left a few questions, mostly to help me understand a bit better what this code is doing.

Copilot reviewed 8 out of 23 changed files in this pull request and generated no comments.

Files not reviewed (15)

• eng/Versions.props: Language not supported
• src/OpenApi/src/Services/OpenApiGenerator.cs: Evaluated as low risk
• src/OpenApi/src/Extensions/OpenApiDocumentExtensions.cs: Evaluated as low risk
• src/OpenApi/sample/Transformers/AddBearerSecuritySchemeTransformer.cs: Evaluated as low risk
• src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiSchemaService/OpenApiSchemaService.PolymorphicSchemas.cs: Evaluated as low risk
• src/OpenApi/src/Services/OpenApiDocumentService.cs: Evaluated as low risk
• src/OpenApi/src/Services/OpenApiConstants.cs: Evaluated as low risk
• src/OpenApi/src/Schemas/OpenApiSchemaKeywords.cs: Evaluated as low risk
• src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiDocumentService/OpenApiDocumentServiceTests.Operations.cs: Evaluated as low risk
• src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Extensions/OpenApiRouteHandlerBuilderExtensionTests.cs: Evaluated as low risk
• src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiDocumentService/OpenApiDocumentServiceTests.Responses.cs: Evaluated as low risk
• src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiSchemaService/OpenApiSchemaService.RequestBodySchemas.cs: Evaluated as low risk
• src/OpenApi/src/Schemas/OpenApiJsonSchema.Helpers.cs: Evaluated as low risk
• src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/CreateSchemaReferenceIdTests.cs: Evaluated as low risk
• src/OpenApi/sample/Program.cs: Evaluated as low risk

Comments suppressed due to low confidence (4)

src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiDocumentServiceTestsBase.cs:89

• The OpenApiSchemaService should be initialized with IOpenApiSchema instead of OpenApiSchema.

var schemaService = new OpenApiSchemaService("Test", Options.Create(new Microsoft.AspNetCore.Http.Json.JsonOptions()), openApiOptions.Object);

src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiDocumentServiceTestsBase.cs:137

• [nitpick] The variable name jsonOptions is ambiguous. It should be renamed to defaultJsonOptions for consistency.

var jsonOptions = builder.ServiceProvider.GetService<IOptions<Microsoft.AspNetCore.Http.Json.JsonOptions>>() ?? Options.Create(defaultJsonOptions);

src/OpenApi/src/Services/Schemas/OpenApiSchemaService.cs:204

• Ensure that the schemaId is present before proceeding. Add a check for schema.Annotations.TryGetValue(OpenApiConstants.SchemaId, out var schemaId) after the ContainsKey check.

if (schema.Annotations.ContainsKey(OpenApiConstants.RefId) &&

src/OpenApi/src/Services/Schemas/OpenApiSchemaService.cs:263

• Ensure that the inputSchema is correctly cast to OpenApiSchema or OpenApiSchemaReference before proceeding. This would prevent any potential runtime errors.

var schema = inputSchema is OpenApiSchemaReference schemaReference

[captainsafia]

@BrennanConroy @DeagleGross Can I get a review on this? I'd love to merge it in before CC on Friday.