Fix conflicting required+nullable schema when only NonNullableReferenceTypesAsRequired is enabled

Author: KitKeen

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

@@ -139,7 +139,7 @@ private bool IsNullable(RequiredAttribute requiredAttribute, DataProperty dataPr
     {
         var nullable = dataProperty.IsNullable && requiredAttribute == null;
 
-        if (_generatorOptions.SupportNonNullableReferenceTypes)
+        if (_generatorOptions.SupportNonNullableReferenceTypes || _generatorOptions.NonNullableReferenceTypesAsRequired)
         {
             nullable &= !memberInfo.IsNonNullableReferenceType();
         }

test/Swashbuckle.AspNetCore.SwaggerGen.Test/SchemaGenerator/JsonSerializerSchemaGeneratorTests.cs

@@ -1126,6 +1126,23 @@ public void GenerateSchema_SupportsOption_SuppressImplicitRequiredAttributeForNo
         Assert.True(propertyIsRequired);
     }
 
+    [Theory]
+    [InlineData(typeof(TypeWithNullableContextAnnotated), nameof(TypeWithNullableContextAnnotated.SubTypeWithOneNonNullableContent), nameof(TypeWithNullableContextAnnotated.NonNullableString))]
+    [InlineData(typeof(TypeWithNullableContextNotAnnotated), nameof(TypeWithNullableContextNotAnnotated.SubTypeWithOneNonNullableContent), nameof(TypeWithNullableContextNotAnnotated.NonNullableString))]
+    public void GenerateSchema_NonNullableReferenceTypesAsRequired_DoesNotMarkPropertyAsNullable(
+        Type declaringType,
+        string subType,
+        string propertyName)
+    {
+        var subject = Subject(c => c.NonNullableReferenceTypesAsRequired = true);
+        var schemaRepository = new SchemaRepository();
+
+        subject.GenerateSchema(declaringType, schemaRepository);
+
+        var propertySchema = schemaRepository.Schemas[subType].Properties[propertyName];
+        AssertIsNullable(propertySchema, expected: false);
+    }
+
     [Theory]
     [InlineData(typeof(TypeWithNullableContextAnnotated), nameof(TypeWithNullableContextAnnotated.SubTypeWithNestedSubType.Nested), nameof(TypeWithNullableContextAnnotated.SubTypeWithNestedSubType.Nested.NullableString), true)]
     [InlineData(typeof(TypeWithNullableContextAnnotated), nameof(TypeWithNullableContextAnnotated.SubTypeWithNestedSubType.Nested), nameof(TypeWithNullableContextAnnotated.SubTypeWithNestedSubType.Nested.NonNullableString), false)]