Fix missing OpenAPI 3.1 $ref properties (#3859)

- Fix missing properties on OpenAPI 3.1 schema references (`default`, `deprecated`).
- Refactor to halve the number of calls to `Type.GetGenericTypeDefinition()` in the worst case.

Resolves #3858.

Author: martincostello

src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/SchemaGenerator.cs

@@ -49,9 +49,28 @@ private IOpenApiSchema GenerateSchemaForMember(
             ? GeneratePolymorphicSchema(schemaRepository, knownTypesDataContracts)
             : GenerateConcreteSchema(dataContract, schemaRepository);
 
-        if (_generatorOptions.UseAllOfToExtendReferenceSchemas && schema is OpenApiSchemaReference reference)
+        if (schema is OpenApiSchemaReference reference)
         {
-            schema = new OpenApiSchema() { AllOf = [reference] };
+            if (_generatorOptions.UseAllOfToExtendReferenceSchemas)
+            {
+                schema = new OpenApiSchema() { AllOf = [reference] };
+            }
+            else
+            {
+                var customAttributes = memberInfo.GetInlineAndMetadataAttributes();
+
+                var defaultValueAttribute = customAttributes.OfType<DefaultValueAttribute>().FirstOrDefault();
+                if (defaultValueAttribute != null)
+                {
+                    reference.Default = GenerateDefaultValue(dataContract, modelType, defaultValueAttribute.Value);
+                }
+
+                var obsoleteAttribute = customAttributes.OfType<ObsoleteAttribute>().FirstOrDefault();
+                if (obsoleteAttribute != null)
+                {
+                    reference.Deprecated = true;
+                }
+            }
         }
 
         if (schema is OpenApiSchema concrete)
@@ -96,9 +115,11 @@ private IOpenApiSchema GenerateSchemaForMember(
                     .Where(t => t.IsGenericType)
                     .ToArray();
 
-                var isDictionaryType =
-                    genericTypes.Any(t => t.GetGenericTypeDefinition() == typeof(IDictionary<,>)) ||
-                    genericTypes.Any(t => t.GetGenericTypeDefinition() == typeof(IReadOnlyDictionary<,>));
+                var isDictionaryType = genericTypes.Any(static (type) =>
+                {
+                    var definition = type.GetGenericTypeDefinition();
+                    return definition == typeof(IDictionary<,>) || definition == typeof(IReadOnlyDictionary<,>);
+                });
 
                 if (isDictionaryType && schema.AdditionalProperties is OpenApiSchema additionalProperties)
                 {
@@ -138,9 +159,25 @@ private IOpenApiSchema GenerateSchemaForParameter(
             ? GeneratePolymorphicSchema(schemaRepository, knownTypesDataContracts)
             : GenerateConcreteSchema(dataContract, schemaRepository);
 
-        if (_generatorOptions.UseAllOfToExtendReferenceSchemas && schema is OpenApiSchemaReference reference)
+        if (schema is OpenApiSchemaReference reference)
         {
-            schema = new OpenApiSchema() { AllOf = [reference] };
+            if (_generatorOptions.UseAllOfToExtendReferenceSchemas)
+            {
+                schema = new OpenApiSchema() { AllOf = [reference] };
+            }
+            else
+            {
+                var customAttributes = parameterInfo.GetCustomAttributes();
+
+                var defaultValue = parameterInfo.HasDefaultValue
+                    ? parameterInfo.DefaultValue
+                    : customAttributes.OfType<DefaultValueAttribute>().FirstOrDefault()?.Value;
+
+                if (defaultValue != null)
+                {
+                    reference.Default = GenerateDefaultValue(dataContract, modelType, defaultValue);
+                }
+            }
         }
 
         if (schema is OpenApiSchema concrete)
@@ -438,7 +475,7 @@ private OpenApiSchema CreateObjectSchema(DataContract dataContract, SchemaReposi
 
             var memberType = dataProperty.MemberType;
 
-            schema.Properties[dataProperty.Name] = (dataProperty.MemberInfo != null)
+            schema.Properties[dataProperty.Name] = dataProperty.MemberInfo != null
                 ? GenerateSchemaForMember(memberType, schemaRepository, dataProperty.MemberInfo, dataProperty)
                 : GenerateSchemaForType(memberType, schemaRepository);
 

test/Swashbuckle.AspNetCore.IntegrationTests/CodeGenerationTests.cs

@@ -33,10 +33,21 @@ public static TheoryData<ClientGeneratorTool, string> SnapshotTestCases()
 
             foreach (var tool in Enum.GetValues<ClientGeneratorTool>())
             {
-                if (tool is ClientGeneratorTool.NSwag && Path.GetFileNameWithoutExtension(path).Contains("Basic.Startup"))
+                var fileName = Path.GetFileNameWithoutExtension(path);
+
+                if (fileName.Contains("Basic.Startup"))
                 {
-                    // NSwag doesn't generate valid compilation due to a missing FileResponse type
-                    continue;
+                    if (tool is ClientGeneratorTool.NSwag)
+                    {
+                        // NSwag doesn't generate valid compilation due to a missing FileResponse type
+                        continue;
+                    }
+
+                    if (!fileName.Contains("=v1."))
+                    {
+                        // Ignore duplicative test cases for Swagger 2.0 and OpenAPI 3.1
+                        continue;
+                    }
                 }
 
                 if (ClientGenerator.IsSupported(tool, "json", version))

test/Swashbuckle.AspNetCore.IntegrationTests/SwaggerIntegrationTests.cs

@@ -11,6 +11,8 @@ public class SwaggerIntegrationTests(ITestOutputHelper outputHelper)
 {
     [Theory]
     [InlineData(typeof(Basic.Startup), "/swagger/v1/swagger.json")]
+    [InlineData(typeof(Basic.Startup), "/swagger/v1/swaggerv2.json")]
+    [InlineData(typeof(Basic.Startup), "/swagger/v1/swaggerv3_1.json")]
     [InlineData(typeof(CliExample.Startup), "/swagger/v1/swagger_net10.0.json")]
     [InlineData(typeof(ConfigFromFile.Startup), "/swagger/v1/swagger.json")]
     [InlineData(typeof(CustomUIConfig.Startup), "/swagger/v1/swagger.json")]

test/Swashbuckle.AspNetCore.IntegrationTests/VerifyTests.cs

@@ -10,6 +10,8 @@ public partial class VerifyTests(ITestOutputHelper outputHelper)
 
     [Theory]
     [InlineData(typeof(Basic.Startup), "/swagger/v1/swagger.json")]
+    [InlineData(typeof(Basic.Startup), "/swagger/v1/swaggerv2.json", "2.0")]
+    [InlineData(typeof(Basic.Startup), "/swagger/v1/swaggerv3_1.json", "3.1")]
     [InlineData(typeof(NSwagClientExample.Startup), "/swagger/v1/swagger.json")]
     [InlineData(typeof(CliExample.Startup), "/swagger/v1/swagger_net10.0.json")]
     [InlineData(typeof(ConfigFromFile.Startup), "/swagger/v1/swagger.json")]
@@ -24,7 +26,8 @@ public partial class VerifyTests(ITestOutputHelper outputHelper)
     [InlineData(typeof(TestFirst.Startup), "/swagger/v1-generated/openapi.json")]
     public async Task SwaggerEndpoint_ReturnsValidSwaggerJson(
         Type startupType,
-        string swaggerRequestUri)
+        string swaggerRequestUri,
+        string openApiVersion = null)
     {
         var testSite = new TestSite(startupType, outputHelper);
         using var client = testSite.BuildClient();
@@ -34,7 +37,7 @@ public async Task SwaggerEndpoint_ReturnsValidSwaggerJson(
 
         await Verify(NormalizeLineBreaks(swagger))
             .UseDirectory(SnapshotsDirectory)
-            .UseParameters(startupType, GetVersion(swaggerRequestUri));
+            .UseParameters(startupType, openApiVersion ?? GetVersion(swaggerRequestUri));
     }
 
     [Fact]