fix reactive multipart

Author: Picazsoo

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/SpringCodegen.java

@@ -799,6 +799,7 @@ public void setIsVoid(boolean isVoid) {
                 prepareVersioningParameters(ops);
                 handleImplicitHeaders(operation);
                 convertByteArrayParamsToStringType(operation);
+                markMultipartFormDataParameters(operation);
             }
             // The tag for the controller is the first tag of the first operation
             final CodegenOperation firstOperation = ops.get(0);
@@ -834,6 +835,44 @@ private void convertByteArrayParamsToStringType(CodegenOperation operation) {
         LOGGER.info("Converted parameters [{}] from byte[] to String in operation [{}]", convertedParams.stream().map(param -> param.paramName).collect(Collectors.toList()), operation.operationId);
     }
 
+    /**
+     * Marks form parameters that are in multipart/form-data operations for special handling in reactive mode.
+     * <p>
+     * In reactive Spring WebFlux, multipart/form-data parameters must use @RequestPart instead of @RequestParam,
+     * and non-model parameters (primitives, enums, strings) must be received as String or Flux&lt;String&gt; and
+     * converted manually in the implementation.
+     * </p>
+     *
+     * @param operation the codegen operation whose parameters will be marked if necessary
+     **/
+    private void markMultipartFormDataParameters(CodegenOperation operation) {
+        if (!reactive) {
+            return; // Only applies to reactive mode
+        }
+
+        // Check if this operation consumes multipart/form-data
+        boolean isMultipartFormData = false;
+        if (operation.hasConsumes) {
+            for (Map<String, String> consume : operation.consumes) {
+                if ("multipart/form-data".equals(consume.get("mediaType"))) {
+                    isMultipartFormData = true;
+                    break;
+                }
+            }
+        }
+
+        if (!isMultipartFormData) {
+            return;
+        }
+
+        // Mark all form parameters as multipart form data
+        for (CodegenParameter param : operation.allParams) {
+            if (param.isFormParam) {
+                param.vendorExtensions.put("x-isMultipartFormData", true);
+            }
+        }
+    }
+
     private interface DataTypeAssigner {
         void setReturnType(String returnType);
 

modules/openapi-generator/src/main/resources/JavaSpring/formParams.mustache

@@ -1 +1 @@
-{{#isFormParam}}{{^isFile}}{{>paramDoc}}{{#useBeanValidation}} {{>beanValidationBodyParams}}@Valid{{/useBeanValidation}} {{#isModel}}@RequestPart{{/isModel}}{{^isModel}}{{#isArray}}{{#items.isModel}}@RequestPart{{/items.isModel}}{{^items.isModel}}@RequestParam{{/items.isModel}}{{/isArray}}{{^isArray}}{{#reactive}}@RequestParam{{/reactive}}{{^reactive}}@RequestParam{{/reactive}}{{/isArray}}{{/isModel}}(value = "{{baseName}}"{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}){{>dateTimeParam}} {{^required}}{{#useOptional}}Optional<{{/useOptional}}{{/required}}{{{dataType}}}{{^required}}{{#useOptional}}>{{/useOptional}}{{/required}} {{paramName}}{{/isFile}}{{#isByteArray}} /* base64 encoded binary */{{/isByteArray}}{{#isFile}}{{>paramDoc}} @RequestPart(value = "{{baseName}}"{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}) {{#reactive}}{{#isArray}}Flux<{{/isArray}}Part{{#isArray}}>{{/isArray}}{{/reactive}}{{^reactive}}{{#isArray}}List<{{/isArray}}MultipartFile{{#isArray}}>{{/isArray}}{{/reactive}} {{paramName}}{{/isFile}}{{/isFormParam}}
+{{#isFormParam}}{{^isFile}}{{>paramDoc}}{{#useBeanValidation}} {{>beanValidationBodyParams}}@Valid{{/useBeanValidation}} {{#isModel}}@RequestPart{{/isModel}}{{^isModel}}{{#isArray}}{{#items.isModel}}@RequestPart{{/items.isModel}}{{^items.isModel}}{{#reactive}}{{#vendorExtensions.x-isMultipartFormData}}@RequestPart{{/vendorExtensions.x-isMultipartFormData}}{{^vendorExtensions.x-isMultipartFormData}}@RequestParam{{/vendorExtensions.x-isMultipartFormData}}{{/reactive}}{{^reactive}}@RequestParam{{/reactive}}{{/items.isModel}}{{/isArray}}{{^isArray}}{{#reactive}}{{#vendorExtensions.x-isMultipartFormData}}@RequestPart{{/vendorExtensions.x-isMultipartFormData}}{{^vendorExtensions.x-isMultipartFormData}}@RequestParam{{/vendorExtensions.x-isMultipartFormData}}{{/reactive}}{{^reactive}}@RequestParam{{/reactive}}{{/isArray}}{{/isModel}}(value = "{{baseName}}"{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}){{>dateTimeParam}} {{^required}}{{#useOptional}}Optional<{{/useOptional}}{{/required}}{{#reactive}}{{#vendorExtensions.x-isMultipartFormData}}{{#isModel}}{{{dataType}}}{{/isModel}}{{^isModel}}{{#isArray}}{{#items.isModel}}{{{dataType}}}{{/items.isModel}}{{^items.isModel}}Flux<String> /* Flux<{{{dataType}}}> */{{/items.isModel}}{{/isArray}}{{^isArray}}String /* {{{dataType}}} */{{/isArray}}{{/isModel}}{{/vendorExtensions.x-isMultipartFormData}}{{^vendorExtensions.x-isMultipartFormData}}{{{dataType}}}{{/vendorExtensions.x-isMultipartFormData}}{{/reactive}}{{^reactive}}{{{dataType}}}{{/reactive}}{{^required}}{{#useOptional}}>{{/useOptional}}{{/required}} {{paramName}}{{/isFile}}{{#isByteArray}} /* base64 encoded binary */{{/isByteArray}}{{#isFile}}{{>paramDoc}} @RequestPart(value = "{{baseName}}"{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}) {{#reactive}}{{#isArray}}Flux<{{/isArray}}Part{{#isArray}}>{{/isArray}}{{/reactive}}{{^reactive}}{{#isArray}}List<{{/isArray}}MultipartFile{{#isArray}}>{{/isArray}}{{/reactive}} {{paramName}}{{/isFile}}{{/isFormParam}}

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/spring/SpringCodegenTest.java

@@ -779,12 +779,12 @@ public void testReactiveMultipartBoot() throws IOException {
 
         // Check that api validates mixed multipart request
         JavaFileAssert.assertThat(files.get("MultipartMixedApi.java"))
-            .assertMethod("multipartMixed", "MultipartMixedStatus", "Part", "MultipartMixedRequestMarker", "List<MultipartMixedRequestMarker>", "List<MultipartMixedStatus>", "ServerWebExchange")
-            .assertParameter("status").hasType("MultipartMixedStatus")
+            .assertMethod("multipartMixed", "String", "Part", "MultipartMixedRequestMarker", "List<MultipartMixedRequestMarker>", "Flux<String>", "ServerWebExchange")
+            .assertParameter("status").hasType("String")
             .assertParameterAnnotations()
             .containsWithName("Valid")
             .containsWithNameAndAttributes("ApiParam", ImmutableMap.of("value", "\"\""))
-            .containsWithNameAndAttributes("RequestParam", ImmutableMap.of("value", "\"status\"", "required", "true"))
+            .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"status\"", "required", "true"))
             .toParameter().toMethod()
             .assertParameter("file").hasType("Part")
             .assertParameterAnnotations()
@@ -799,9 +799,9 @@ public void testReactiveMultipartBoot() throws IOException {
             .assertParameterAnnotations()
             .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"markerArray\"", "required", "false"))
             .toParameter().toMethod()
-            .assertParameter("statusArray").hasType("List<MultipartMixedStatus>")
+            .assertParameter("statusArray").hasType("Flux<String>")
             .assertParameterAnnotations()
-            .containsWithNameAndAttributes("RequestParam", ImmutableMap.of("value", "\"statusArray\"", "required", "false"));
+            .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"statusArray\"", "required", "false"));
     }
 
     @Test
@@ -4923,9 +4923,8 @@ public void givenMultipartForm_whenGenerateReactiveServer_thenParameterAreCreate
         generator.setGeneratorPropertyDefault(CodegenConstants.APIS, "true");
 
         generator.opts(input).generate();
-        // Only file or object types would use @RequestPart
         assertFileContains(Paths.get(outputPath + "/src/main/java/org/openapitools/api/PetApi.java"),
-                "@Valid @RequestParam(value = \"additionalMetadata\", required = false) String additionalMetadata");
+                "@Valid @RequestPart(value = \"additionalMetadata\", required = false) String /* String */ additionalMetadata");
     }
 
     @Test