Fix required handling for formdata properties

src/NSwag.Generation.AspNetCore.Tests.Web/Controllers/Parameters/FileUploadController.cs

@@ -36,5 +36,21 @@ public class CaseAttachmentModel
 
             public IFormFile Contents { get; set; }
         }
+
+        [HttpPost("UploadAttachment2")]
+        public Task<IActionResult> UploadAttachment2(
+            [FromForm][Required] CaseAttachmentModel2 model,
+            [Required] IFormFile contents)
+        {
+            return Task.FromResult<IActionResult>(Ok());
+        }
+
+        public class CaseAttachmentModel2
+        {
+            [Required]
+            public string Title { get; init; }
+
+            public int? MessageId { get; set; }
+        }
     }
 }

src/NSwag.Generation.AspNetCore.Tests/Parameters/FormDataTests.cs

@@ -102,5 +102,56 @@ public async Task WhenOperationHasFormDataComplex_ThenItIsInRequestBody()
           }
         },".Replace("\r", ""), json.Replace("\r", ""));
         }
+
+        [Fact]
+        public async Task WhenOperationHasFormDataComplexWithRequiredProperties_ThenItIsInRequestBody()
+        {
+            // Arrange
+            var settings = new AspNetCoreOpenApiDocumentGeneratorSettings
+            {
+                SchemaSettings = new NewtonsoftJsonSchemaGeneratorSettings
+                {
+                    SchemaType = SchemaType.OpenApi3
+                }
+            };
+
+            // Act
+            var document = await GenerateDocumentAsync(settings, typeof(FileUploadController));
+            var json = document.ToJson();
+
+            // Assert
+            var operation = document.Operations.First(o => o.Operation.OperationId == "FileUpload_UploadAttachment2").Operation;
+
+            Assert.NotNull(operation);
+            Assert.Contains(@"""requestBody"": {
+          ""content"": {
+            ""multipart/form-data"": {
+              ""schema"": {
+                ""type"": ""object"",
+                ""required"": [
+                  ""Title"",
+                  ""contents""
+                ],
+                ""properties"": {
+                  ""Title"": {
+                    ""type"": ""string"",
+                    ""nullable"": false
+                  },
+                  ""MessageId"": {
+                    ""type"": ""integer"",
+                    ""format"": ""int32"",
+                    ""nullable"": true
+                  },
+                  ""contents"": {
+                    ""type"": ""string"",
+                    ""format"": ""binary"",
+                    ""nullable"": false
+                  }
+                }
+              }
+            }
+          }
+        },".Replace("\r", ""), json.Replace("\r", ""));
+        }
     }
 }

src/NSwag.Generation.AspNetCore/Processors/OperationParameterProcessor.cs

@@ -348,10 +348,18 @@ private JsonSchema CreateOrGetFormDataSchema(OperationProcessorContext context)
             return requestBody.Content[MultipartFormData].Schema;
         }
 
-        private static JsonSchemaProperty CreateFormDataProperty(OperationProcessorContext context, ExtendedApiParameterDescription extendedApiParameter, JsonSchema schema)
+        private JsonSchemaProperty CreateFormDataProperty(OperationProcessorContext context, ExtendedApiParameterDescription extendedApiParameter, JsonSchema schema)
         {
-            return context.SchemaGenerator.GenerateWithReferenceAndNullability<JsonSchemaProperty>(
+            var formDataProperty = context.SchemaGenerator.GenerateWithReferenceAndNullability<JsonSchemaProperty>(
                extendedApiParameter.ApiParameter.Type.ToContextualType(extendedApiParameter.Attributes), context.SchemaResolver);
+
+            var contextualPropertyType = extendedApiParameter.ParameterType.ToContextualType();
+            var typeDescription = _settings.SchemaSettings.ReflectionService.GetDescription(contextualPropertyType, _settings.SchemaSettings);
+            var isRequired = extendedApiParameter.IsRequired(_settings.RequireParametersWithoutDefault);
+            formDataProperty.IsRequired = isRequired;
+            formDataProperty.IsNullableRaw = _settings.AllowNullableBodyParameters && !isRequired && typeDescription.IsNullable;
+
+            return formDataProperty;
         }
 
         private bool IsFileArray(Type type, JsonTypeDescription typeInfo)
@@ -527,7 +535,7 @@ public bool IsRequired(bool requireParametersWithoutDefault)
                 // available in asp.net core >= 2.2
                 if (ApiParameter.HasProperty("IsRequired"))
                 {
-                    isRequired = ApiParameter.TryGetPropertyValue("IsRequired", false);
+                    isRequired = ApiParameter.TryGetPropertyValue("IsRequired", false) || ApiParameter.ModelMetadata?.IsRequired == true;
                 }
                 else
                 {
@@ -538,7 +546,6 @@ public bool IsRequired(bool requireParametersWithoutDefault)
                     }
                     else if (ApiParameter.ModelMetadata != null &&
                              ApiParameter.ModelMetadata.IsBindingRequired)
-
                     {
                         isRequired = true;
                     }