[python][flask] Honor defaultController option for untagged operations

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

@@ -308,8 +308,13 @@ public String getHelp() {
 
     @Override
     public String toApiName(String name) {
-        if (name == null || name.length() == 0) {
-            return "DefaultController";
+        if (name == null || name.length() == 0 || "default".equalsIgnoreCase(name)) {
+            // Operations without a tag are grouped under the "default" tag. Honor the
+            // configurable defaultController module name for them (issue #1891); this
+            // drives both the generated controller file name and connexion's
+            // x-openapi-router-controller routing, keeping the two consistent.
+            String controller = defaultController != null ? defaultController : "default_controller";
+            return camelize(controller);
         }
         return camelize(name) + "Controller";
     }

modules/openapi-generator/src/test/java/org/openapitools/codegen/python/PythonFlaskConnexionServerCodegenTest.java

@@ -67,4 +67,25 @@ public void testRequestBody() throws IOException {
         assertFileContains(p4, "def with_path_param_required(param1, body):");
         assertFileContains(p4, "test_request = body");
     }
+
+    @Test(description = "the defaultController option controls the module name for untagged operations (issue #1891)")
+    public void testDefaultController() throws IOException {
+        final PythonFlaskConnexionServerCodegen codegen = new PythonFlaskConnexionServerCodegen();
+        codegen.additionalProperties().put("defaultController", "my_default_controller");
+        final String outputPath = generateFiles(codegen, "src/test/resources/bugs/issue_1891.yaml");
+
+        // The untagged operation should land in the configured controller module...
+        final Path expected = Paths.get(outputPath + "openapi_server/controllers/my_default_controller.py");
+        assertFileExists(expected);
+        assertFileContains(expected, "def ping():");
+
+        // ...and connexion's routing must point at the same module, not the hardcoded default.
+        final Path openapiYaml = Paths.get(outputPath + "openapi_server/openapi/openapi.yaml");
+        assertFileContains(openapiYaml, "x-openapi-router-controller: openapi_server.controllers.my_default_controller");
+
+        // The hardcoded default_controller.py must no longer be emitted.
+        final Path old = Paths.get(outputPath + "openapi_server/controllers/default_controller.py");
+        Assert.assertFalse(Files.exists(old),
+                "Untagged operations should honor defaultController, not fall back to default_controller.py");
+    }
 }

modules/openapi-generator/src/test/resources/bugs/issue_1891.yaml

@@ -0,0 +1,11 @@
+openapi: 3.0.0
+info:
+  title: Issue 1891 - defaultController
+  version: 1.0.0
+paths:
+  /ping:
+    get:
+      operationId: ping
+      responses:
+        '200':
+          description: ok