fix(cpp-qt): Fix enum query parameter serialization for both inline and referenced enums (#22559)

* fix(cpp-qt): Fix enum query parameter serialization for both inline and referenced enums

For enum query parameters, the template was incorrectly using asJsonObject()
which returns {"value": "enumValue"} and then iterating over keys, using
"value" as the parameter name instead of the actual parameter name.

This fix adds special handling for both inline enums (isEnum) and referenced
enums (isEnumRef) to use asJson() directly, which returns the correct enum
string value for URL serialization.

Fixes enum query parameters like ?scope=property instead of ?value=property.

Completes the fix started in PR #21211 which added the asJsonObject() method
to make enum code compile, but the template logic was still incorrect for URL
query parameter serialization.

Note: The petstore samples don't contain enum query parameter tests to
demonstrate this fix (they use string arrays). Future contributors may want
to add enum query parameter examples to better showcase this functionality.

* add tests for enum inline, ref for query parameters

* update cmake version to 3.5

---------

Co-authored-by: Sohaib Athar <[email protected]>

Author: wing328

modules/openapi-generator/src/main/resources/cpp-qt-client/api-body.mustache

@@ -344,6 +344,21 @@ void {{classname}}::{{nickname}}({{#allParams}}{{#required}}const {{{dataType}}}
         else
             fullPath.append("?");
         {{^isPrimitiveType}}
+        {{#isEnum}}
+        // For enum parameters, use direct string serialization instead of object iteration
+        QString enumValue = {{paramName}}{{^required}}.value(){{/required}}.asJson();
+        if (!enumValue.isEmpty()) {
+            fullPath.append(QUrl::toPercentEncoding("{{baseName}}")).append("=").append(QUrl::toPercentEncoding(enumValue));
+        }
+        {{/isEnum}}
+        {{#isEnumRef}}
+        // For enum reference parameters, use direct string serialization instead of object iteration
+        QString enumValue = {{paramName}}{{^required}}.value(){{/required}}.asJson();
+        if (!enumValue.isEmpty()) {
+            fullPath.append(QUrl::toPercentEncoding("{{baseName}}")).append("=").append(QUrl::toPercentEncoding(enumValue));
+        }
+        {{/isEnumRef}}
+        {{^isEnum}}{{^isEnumRef}}
         QString paramString = (queryStyle == "form" && {{isExplode}}) ? "" : (queryStyle == "form" && !({{isExplode}})) ? "{{baseName}}"+querySuffix : "";
         QJsonObject parameter = {{paramName}}{{^required}}.value(){{/required}}.asJsonObject();
         qint32 count = 0;
@@ -390,6 +405,7 @@ void {{classname}}::{{nickname}}({{#allParams}}{{#required}}const {{{dataType}}}
             count++;
         }
         fullPath.append(paramString);
+        {{/isEnumRef}}{{/isEnum}}
         {{/isPrimitiveType}}{{#isPrimitiveType}}
         fullPath.append(QUrl::toPercentEncoding("{{baseName}}")).append(querySuffix).append(QUrl::toPercentEncoding(::{{cppNamespace}}::toStringValue({{paramName}}{{^required}}.stringValue(){{/required}})));
 {{/isPrimitiveType}}

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

@@ -572,6 +572,35 @@ paths:
           description: Invalid username supplied
         "404":
           description: User not found
+  "/fake/enum_inline_or_ref":
+    get:
+      tags:
+        - fake
+      summary: fake endpoint to test enum (inline or ref)
+      description: ""
+      operationId: get_enum_inline_or_ref
+      parameters:
+        - name: enum_inline
+          in: query
+          description: Enum status inline
+          schema:
+            type: string
+            enum:
+              - placed
+              - approved
+              - delivered
+        - name: enum_ref
+          in: query
+          description: Enum status
+          schema:
+            $ref: "#/components/schemas/EnumStatus"
+      responses:
+        "200":
+          description: successful operation
+        "400":
+          description: Invalid username supplied
+        "404":
+          description: User not found
 servers:
   - url: http://petstore.swagger.io/v2
   - url: http://localhost:8080/v2
@@ -610,6 +639,13 @@ components:
       name: api_key
       in: header
   schemas:
+    EnumStatus:
+      type: string
+      description: Order Status
+      enum:
+        - placed
+        - approved
+        - delivered
     Order:
       title: Pet Order
       description: An order for a pets from the pet store

samples/client/petstore/cpp-qt-addDownloadProgress/.openapi-generator/FILES

@@ -6,6 +6,10 @@ client/PFXApiResponse.h
 client/PFXCategory.cpp
 client/PFXCategory.h
 client/PFXEnum.h
+client/PFXEnumStatus.cpp
+client/PFXEnumStatus.h
+client/PFXFakeApi.cpp
+client/PFXFakeApi.h
 client/PFXHelpers.cpp
 client/PFXHelpers.h
 client/PFXHttpFileElement.cpp

samples/client/petstore/cpp-qt-addDownloadProgress/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.2)
+cmake_minimum_required(VERSION 3.5)
 
 project(cpp-qt-petstore)
 set(CMAKE_VERBOSE_MAKEFILE ON)

samples/client/petstore/cpp-qt-addDownloadProgress/README.md

@@ -27,13 +27,14 @@ example.h:
 ```c++
 
 #include <iostream>
-#include "../client/PFXPetApi.h"
+#include "../client/PFXFakeApi.h"
 
 using namespace test_namespace;
 
 class Example : public QObject {
     Q_OBJECT
-    PFXPet create();
+    QString create();
+    PFXEnumStatus create();
 public Q_SLOTS:
    void exampleFunction1();
 };
@@ -43,32 +44,43 @@ public Q_SLOTS:
 example.cpp:
 ```c++
 
-#include "../client/PFXPetApi.h"
+#include "../client/PFXFakeApi.h"
 #include "example.h"
 #include <QTimer>
 #include <QEventLoop>
 
-PFXPet Example::create(){
-    PFXPet obj;
+QString Example::create(){
+    QString obj;
+PFXEnumStatus Example::create(){
+    PFXEnumStatus obj;
  return obj;
 }
 
 void Example::exampleFunction1(){
-     PFXPetApi apiInstance;
+     PFXFakeApi apiInstance;
      
-      //OAuth Authentication supported right now
+      QEventLoop loop;
+      connect(&apiInstance, &PFXFakeApi::getEnumInlineOrRefSignal, [&]() {
+          loop.quit();
+      });
+      connect(&apiInstance, &PFXFakeApi::getEnumInlineOrRefSignalE, [&](QNetworkReply::NetworkError, QString error_str) {
+          qDebug() << "Error happened while issuing request : " << error_str;
+          loop.quit();
+      });
+
+      QString enum_inline = create(); // QString | Enum status inline
 
       QEventLoop loop;
-      connect(&apiInstance, &PFXPetApi::addPetSignal, [&]() {
+      connect(&apiInstance, &PFXFakeApi::getEnumInlineOrRefSignal, [&]() {
           loop.quit();
       });
-      connect(&apiInstance, &PFXPetApi::addPetSignalE, [&](QNetworkReply::NetworkError, QString error_str) {
+      connect(&apiInstance, &PFXFakeApi::getEnumInlineOrRefSignalE, [&](QNetworkReply::NetworkError, QString error_str) {
           qDebug() << "Error happened while issuing request : " << error_str;
           loop.quit();
       });
 
-      PFXPet pfx_pet = create(); // PFXPet | Pet object that needs to be added to the store
-      apiInstance.addPet(pfx_pet);
+      PFXEnumStatus enum_ref = create(); // PFXEnumStatus | Enum status
+      apiInstance.getEnumInlineOrRef(enum_inlineenum_ref);
       QTimer::singleShot(5000, &loop, &QEventLoop::quit);
       loop.exec();
   }

samples/client/petstore/cpp-qt-addDownloadProgress/client/CMakeLists.txt

@@ -13,11 +13,13 @@ include(CMakePackageConfigHelpers)
 add_library(${PROJECT_NAME}
   PFXApiResponse.h
   PFXCategory.h
+  PFXEnumStatus.h
   PFXOrder.h
   PFXPet.h
   PFXTag.h
   PFXTestAnyType.h
   PFXUser.h
+  PFXFakeApi.h
   PFXPetApi.h
   PFXPrimitivesApi.h
   PFXStoreApi.h
@@ -32,11 +34,13 @@ add_library(${PROJECT_NAME}
   PFXOauth.h
   PFXApiResponse.cpp
   PFXCategory.cpp
+  PFXEnumStatus.cpp
   PFXOrder.cpp
   PFXPet.cpp
   PFXTag.cpp
   PFXTestAnyType.cpp
   PFXUser.cpp
+  PFXFakeApi.cpp
   PFXPetApi.cpp
   PFXPrimitivesApi.cpp
   PFXStoreApi.cpp

samples/client/petstore/cpp-qt-addDownloadProgress/client/PFXEnumStatus.cpp

@@ -0,0 +1,104 @@
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+#include "PFXEnumStatus.h"
+
+#include <QDebug>
+#include <QJsonArray>
+#include <QJsonDocument>
+#include <QObject>
+
+#include "PFXHelpers.h"
+
+namespace test_namespace {
+
+PFXEnumStatus::PFXEnumStatus(QString json) {
+    this->initializeModel();
+    this->fromJson(json);
+}
+
+PFXEnumStatus::PFXEnumStatus() {
+    this->initializeModel();
+}
+
+PFXEnumStatus::~PFXEnumStatus() {}
+
+void PFXEnumStatus::initializeModel() {
+
+    m_value_isSet = false;
+    m_value_isValid = false;
+    m_value = ePFXEnumStatus::INVALID_VALUE_OPENAPI_GENERATED;
+}
+
+void PFXEnumStatus::fromJson(QString jsonString) {
+    
+    if ( jsonString.compare("placed", Qt::CaseInsensitive) == 0) {
+        m_value = ePFXEnumStatus::PLACED;
+        m_value_isSet = m_value_isValid = true;
+    }
+    else if ( jsonString.compare("approved", Qt::CaseInsensitive) == 0) {
+        m_value = ePFXEnumStatus::APPROVED;
+        m_value_isSet = m_value_isValid = true;
+    }
+    else if ( jsonString.compare("delivered", Qt::CaseInsensitive) == 0) {
+        m_value = ePFXEnumStatus::DELIVERED;
+        m_value_isSet = m_value_isValid = true;
+    }
+}
+
+void PFXEnumStatus::fromJsonValue(QJsonValue json) {
+fromJson(json.toString());
+}
+
+QString PFXEnumStatus::asJson() const {
+    
+    QString val;
+    switch (m_value){
+        case ePFXEnumStatus::PLACED:
+            val = "placed";
+            break;
+        case ePFXEnumStatus::APPROVED:
+            val = "approved";
+            break;
+        case ePFXEnumStatus::DELIVERED:
+            val = "delivered";
+            break;
+        default:
+            break;
+    }
+    return val;
+}
+
+QJsonValue PFXEnumStatus::asJsonValue() const {
+    
+    return QJsonValue(asJson());
+}
+
+
+PFXEnumStatus::ePFXEnumStatus PFXEnumStatus::getValue() const {
+    return m_value;
+}
+
+void PFXEnumStatus::setValue(const PFXEnumStatus::ePFXEnumStatus& value){
+    m_value = value;
+    m_value_isSet = true;
+}
+bool PFXEnumStatus::isSet() const {
+    
+    return m_value_isSet;
+}
+
+bool PFXEnumStatus::isValid() const {
+    // only required properties are required for the object to be considered valid
+    return m_value_isValid;
+}
+
+} // namespace test_namespace

samples/client/petstore/cpp-qt-addDownloadProgress/client/PFXEnumStatus.h

@@ -0,0 +1,63 @@
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+/*
+ * PFXEnumStatus.h
+ *
+ * Order Status
+ */
+
+#ifndef PFXEnumStatus_H
+#define PFXEnumStatus_H
+
+#include <QJsonObject>
+
+
+#include "PFXEnum.h"
+#include "PFXObject.h"
+
+namespace test_namespace {
+
+class PFXEnumStatus : public PFXEnum {
+public:
+    PFXEnumStatus();
+    PFXEnumStatus(QString json);
+    ~PFXEnumStatus() override;
+
+    QString asJson() const override;
+    QJsonValue asJsonValue() const override;
+    void fromJsonValue(QJsonValue json) override;
+    void fromJson(QString jsonString) override;
+
+    enum class ePFXEnumStatus {
+        INVALID_VALUE_OPENAPI_GENERATED = 0,
+        PLACED, 
+        APPROVED, 
+        DELIVERED
+    };
+    PFXEnumStatus::ePFXEnumStatus getValue() const;
+    void setValue(const PFXEnumStatus::ePFXEnumStatus& value);
+    virtual bool isSet() const override;
+    virtual bool isValid() const override;
+
+private:
+    void initializeModel();
+
+    ePFXEnumStatus m_value;
+    bool m_value_isSet;
+    bool m_value_isValid;
+};
+
+} // namespace test_namespace
+
+Q_DECLARE_METATYPE(test_namespace::PFXEnumStatus)
+
+#endif // PFXEnumStatus_H