[Rust] Enum Query Parameter Serialization Fixes

bin/configs/rust-reqwest-multipart-async.yaml

@@ -0,0 +1,9 @@
+generatorName: rust
+outputDir: samples/client/others/rust/reqwest/multipart-async
+library: reqwest
+inputSpec: modules/openapi-generator/src/test/resources/3_0/rust/multipart-file-upload.yaml
+templateDir: modules/openapi-generator/src/main/resources/rust
+additionalProperties:
+  supportAsync: true
+  useSingleRequestParameter: true
+  packageName: multipart-upload-reqwest-async

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

@@ -741,7 +741,7 @@ public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<Mo
             }
 
             // If we use a file body parameter, we need to include the imports and crates for it
-            // But they should be added only once per file 
+            // But they should be added only once per file
             for (var param: operation.bodyParams) {
                 if (param.isFile && supportAsync && !useAsyncFileStream) {
                     useAsyncFileStream = true;
@@ -751,6 +751,18 @@ public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<Mo
                 }
             }
 
+            // Also check form params for file uploads (multipart)
+            if (!useAsyncFileStream) {
+                for (var param: operation.formParams) {
+                    if (param.isFile && supportAsync) {
+                        useAsyncFileStream = true;
+                        additionalProperties.put("useAsyncFileStream", Boolean.TRUE);
+                        operation.vendorExtensions.put("useAsyncFileStream", Boolean.TRUE);
+                        break;
+                    }
+                }
+            }
+
             // http method verb conversion, depending on client library (e.g. Hyper: PUT => Put, Reqwest: PUT => put)
             if (HYPER_LIBRARY.equals(getLibrary())) {
                 operation.httpMethod = StringUtils.camelize(operation.httpMethod.toLowerCase(Locale.ROOT));

modules/openapi-generator/src/main/resources/rust/model.mustache

@@ -167,7 +167,7 @@ impl {{{classname}}} {
     }}{{^-last}}, {{/-last}}{{/requiredVars}}) -> {{{classname}}} {
         {{{classname}}} {
             {{#vars}}
-            {{{name}}}{{^required}}: None{{/required}}{{#required}}{{#isModel}}{{^avoidBoxedModels}}: {{^isNullable}}Box::new({{{name}}}){{/isNullable}}{{#isNullable}}if let Some(x) = {{{name}}} {Some(Box::new(x))} else {None}{{/isNullable}}{{/avoidBoxedModels}}{{/isModel}}{{/required}},
+            {{{name}}}{{^required}}: None{{/required}}{{#required}}{{^isEnum}}{{#isModel}}{{^avoidBoxedModels}}: {{^isNullable}}Box::new({{{name}}}){{/isNullable}}{{#isNullable}}if let Some(x) = {{{name}}} {Some(Box::new(x))} else {None}{{/isNullable}}{{/avoidBoxedModels}}{{/isModel}}{{/isEnum}}{{/required}},
             {{/vars}}
         }
     }

modules/openapi-generator/src/main/resources/rust/reqwest/api.mustache

@@ -204,6 +204,7 @@ pub {{#supportAsync}}async {{/supportAsync}}fn {{{operationId}}}(configuration:
     {{^isObject}}
     {{^isModel}}
     {{^isEnum}}
+    {{^isEnumRef}}
     {{#isPrimitiveType}}
     if let Some(ref param_value) = {{{vendorExtensions.x-rust-param-identifier}}} {
         req_builder = req_builder.query(&[("{{{baseName}}}", &param_value.to_string())]);
@@ -214,7 +215,18 @@ pub {{#supportAsync}}async {{/supportAsync}}fn {{{operationId}}}(configuration:
         req_builder = req_builder.query(&[("{{{baseName}}}", &serde_json::to_string(param_value)?)]);
     };
     {{/isPrimitiveType}}
+    {{/isEnumRef}}
     {{/isEnum}}
+    {{#isEnum}}
+    if let Some(ref param_value) = {{{vendorExtensions.x-rust-param-identifier}}} {
+        req_builder = req_builder.query(&[("{{{baseName}}}", &param_value.to_string())]);
+    };
+    {{/isEnum}}
+    {{#isEnumRef}}
+    if let Some(ref param_value) = {{{vendorExtensions.x-rust-param-identifier}}} {
+        req_builder = req_builder.query(&[("{{{baseName}}}", &param_value.to_string())]);
+    };
+    {{/isEnumRef}}
     {{/isModel}}
     {{/isObject}}
     {{/isNullable}}
@@ -255,17 +267,22 @@ pub {{#supportAsync}}async {{/supportAsync}}fn {{{operationId}}}(configuration:
         req_builder = req_builder.query(&[("{{{baseName}}}", &serde_json::to_string(param_value)?)]);
         {{/isModel}}
         {{#isEnum}}
-        req_builder = req_builder.query(&[("{{{baseName}}}", &serde_json::to_string(param_value)?)]);
+        req_builder = req_builder.query(&[("{{{baseName}}}", &param_value.to_string())]);
         {{/isEnum}}
+        {{#isEnumRef}}
+        req_builder = req_builder.query(&[("{{{baseName}}}", &param_value.to_string())]);
+        {{/isEnumRef}}
         {{^isObject}}
         {{^isModel}}
         {{^isEnum}}
+        {{^isEnumRef}}
         {{#isPrimitiveType}}
         req_builder = req_builder.query(&[("{{{baseName}}}", &param_value.to_string())]);
         {{/isPrimitiveType}}
         {{^isPrimitiveType}}
         req_builder = req_builder.query(&[("{{{baseName}}}", &serde_json::to_string(param_value)?)]);
         {{/isPrimitiveType}}
+        {{/isEnumRef}}
         {{/isEnum}}
         {{/isModel}}
         {{/isObject}}
@@ -405,11 +422,17 @@ pub {{#supportAsync}}async {{/supportAsync}}fn {{{operationId}}}(configuration:
     {{#supportAsync}}
     {{^required}}
     if let Some(ref param_value) = {{{vendorExtensions.x-rust-param-identifier}}} {
-       multipart_form = multipart_form.file("{{{baseName}}}", param_value.as_os_str()).await?;
+        let file_bytes = tokio::fs::read(param_value).await?;
+        let file_name = param_value.file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_default();
+        let file_part = reqwest::multipart::Part::bytes(file_bytes).file_name(file_name);
+        multipart_form = multipart_form.part("{{{baseName}}}", file_part);
     }
     {{/required}}
     {{#required}}
-    multipart_form = multipart_form.file("{{{baseName}}}", {{{vendorExtensions.x-rust-param-identifier}}}.as_os_str()).await?;
+    let file_bytes = tokio::fs::read(&{{{vendorExtensions.x-rust-param-identifier}}}).await?;
+    let file_name = {{{vendorExtensions.x-rust-param-identifier}}}.file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_default();
+    let file_part = reqwest::multipart::Part::bytes(file_bytes).file_name(file_name);
+    multipart_form = multipart_form.part("{{{baseName}}}", file_part);
     {{/required}}
     {{/supportAsync}}
     {{/isFile}}

modules/openapi-generator/src/test/resources/3_0/rust/multipart-file-upload.yaml

@@ -0,0 +1,123 @@
+openapi: 3.0.3
+info:
+  title: Multipart File Upload Test
+  description: Regression test for async multipart file uploads with tokio::fs
+  version: 1.0.0
+servers:
+  - url: http://localhost:8080
+paths:
+  /upload/single:
+    post:
+      operationId: uploadSingleFile
+      summary: Upload a single file (required parameter)
+      description: Tests async multipart file upload with required file parameter
+      requestBody:
+        required: true
+        content:
+          multipart/form-data:
+            schema:
+              type: object
+              required:
+                - file
+                - description
+              properties:
+                description:
+                  type: string
+                  description: File description metadata
+                file:
+                  type: string
+                  format: binary
+                  description: File to upload
+      responses:
+        '200':
+          description: Upload successful
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/UploadResponse'
+        '400':
+          description: Bad request
+
+  /upload/optional:
+    post:
+      operationId: uploadOptionalFile
+      summary: Upload an optional file
+      description: Tests async multipart file upload with optional file parameter
+      requestBody:
+        content:
+          multipart/form-data:
+            schema:
+              type: object
+              properties:
+                metadata:
+                  type: string
+                  description: Optional metadata string
+                file:
+                  type: string
+                  format: binary
+                  description: Optional file to upload
+      responses:
+        '200':
+          description: Upload successful
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/UploadResponse'
+
+  /upload/multiple-fields:
+    post:
+      operationId: uploadMultipleFields
+      summary: Upload with multiple form fields
+      description: Tests async multipart with multiple files and text fields
+      requestBody:
+        content:
+          multipart/form-data:
+            schema:
+              type: object
+              required:
+                - primaryFile
+              properties:
+                title:
+                  type: string
+                  description: Upload title
+                tags:
+                  type: array
+                  items:
+                    type: string
+                  description: Tags for the upload
+                primaryFile:
+                  type: string
+                  format: binary
+                  description: Primary file (required)
+                thumbnail:
+                  type: string
+                  format: binary
+                  description: Optional thumbnail file
+      responses:
+        '200':
+          description: Upload successful
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/UploadResponse'
+        '400':
+          description: Bad request
+
+components:
+  schemas:
+    UploadResponse:
+      type: object
+      required:
+        - success
+        - fileCount
+      properties:
+        success:
+          type: boolean
+          description: Whether the upload was successful
+        fileCount:
+          type: integer
+          format: int32
+          description: Number of files uploaded
+        message:
+          type: string
+          description: Optional message about the upload

modules/openapi-generator/src/test/resources/3_0/rust/petstore.yaml

@@ -719,6 +719,50 @@ paths:
             application/json:
               schema:
                 type: string
+  '/tests/inlineEnumBoxing':
+    post:
+      tags:
+        - testing
+      summary: 'Test for inline enum fields not being boxed in model constructors'
+      description: 'Regression test to ensure inline enum fields are not wrapped in Box::new() in model constructors'
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/ModelWithInlineEnum'
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ModelWithInlineEnum'
+    get:
+      tags:
+        - testing
+      summary: 'Get model with inline enums'
+      description: 'Tests inline enum query parameters'
+      parameters:
+        - name: status
+          in: query
+          description: Filter by status (inline enum)
+          required: false
+          schema:
+            type: string
+            enum:
+              - draft
+              - published
+              - archived
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/ModelWithInlineEnum'
 externalDocs:
   description: Find out more about Swagger
   url: 'http://swagger.io'
@@ -1128,6 +1172,38 @@ components:
           oneOf:
             - $ref: '#/components/schemas/Order'
             - $ref: '#/components/schemas/Order'
+    ModelWithInlineEnum:
+      type: object
+      required:
+        - status
+      properties:
+        id:
+          type: integer
+          format: int64
+          description: Model ID
+        status:
+          type: string
+          description: Status with inline enum (tests inline enum not being boxed in constructor)
+          enum:
+            - draft
+            - published
+            - archived
+        priority:
+          type: string
+          description: Priority level (optional inline enum)
+          enum:
+            - low
+            - medium
+            - high
+            - critical
+        metadata:
+          type: object
+          description: Optional metadata object
+          properties:
+            tags:
+              type: array
+              items:
+                type: string
     Page:
       type: object
       properties: