[C++][Qt]Replace usage of QVariant with a more intuitive optional wrapper (#8960)

* Replace usage of QVariant with a more intuitive wrapper which also supports non standard types/classes

* Fix crash due to usage of object instead of reference

Author: etherealjoy

modules/openapi-generator/src/main/resources/cpp-qt5-client/api-body.mustache

@@ -2,6 +2,7 @@
 #ifndef {{prefix}}_{{classname}}_H
 #define {{prefix}}_{{classname}}_H
 
+#include "{{prefix}}Helpers.h"
 #include "{{prefix}}HttpRequest.h"
 #include "{{prefix}}ServerConfiguration.h"
 
@@ -13,7 +14,6 @@
 #include <QStringList>
 #include <QList>
 #include <QNetworkAccessManager>
-#include <QVariant>
 
 {{#cppNamespaceDeclarations}}
 namespace {{this}} {
@@ -57,7 +57,7 @@ public:
     {{/required}}
     {{/allParams}}
     */{{/hasParams}}
-    {{#isDeprecated}}Q_DECL_DEPRECATED {{/isDeprecated}}void {{nickname}}({{#allParams}}{{#required}}const {{{dataType}}} &{{/required}}{{^required}}const QVariant &{{/required}}{{paramName}}{{^required}} = QVariant(){{/required}}{{^-last}}, {{/-last}}{{/allParams}});
+    {{#isDeprecated}}Q_DECL_DEPRECATED {{/isDeprecated}}void {{nickname}}({{#allParams}}{{#required}}const {{{dataType}}} &{{/required}}{{^required}}const ::{{cppNamespace}}::OptionalParam<{{{dataType}}}> &{{/required}}{{paramName}}{{^required}} = ::{{cppNamespace}}::OptionalParam<{{{dataType}}}>(){{/required}}{{^-last}}, {{/-last}}{{/allParams}});
 {{/operation}}{{/operations}}
 
 private:
@@ -86,7 +86,7 @@ signals:
 {{#operations}}{{#operation}}
     void {{nickname}}SignalEFull({{prefix}}HttpRequestWorker *worker, QNetworkReply::NetworkError error_type, QString error_str);{{/operation}}{{/operations}}
 
-    void abortRequestsSignal(); 
+    void abortRequestsSignal();
     void allPendingRequestsCompleted();
 };
 

modules/openapi-generator/src/main/resources/cpp-qt5-client/api-header.mustache

@@ -11,7 +11,6 @@
 #include <QList>
 #include <QMap>
 #include <QSet>
-#include <QVariant>
 
 #include "{{prefix}}Enum.h"
 #include "{{prefix}}HttpFileElement.h"
@@ -21,6 +20,27 @@
 namespace {{this}} {
 {{/cppNamespaceDeclarations}}
 
+template <typename T>
+class OptionalParam {
+public:
+    T m_Value;
+    bool m_hasValue;
+public:
+    OptionalParam(){
+        m_hasValue = false;
+    }
+    OptionalParam(const T &val){
+        m_hasValue = true;
+        m_Value = val;
+    }
+    bool hasValue() const {
+        return m_hasValue;
+    }
+    T value() const{
+        return m_Value;
+    }
+};
+
 bool setDateTimeFormat(const QString&);
 
 template <typename T>

modules/openapi-generator/src/main/resources/cpp-qt5-client/helpers-header.mustache

@@ -217,6 +217,7 @@ void PetApiTests::updatePetWithFormTest() {
     // fetch it
     bool petUpdated2 = false;
     connect(&api, &PFXPetApi::getPetByIdSignal, [&](PFXPet pet) {
+        Q_UNUSED(pet);
         petUpdated2 = true;
 //      QVERIFY(pet.getName().compare(QString("gorilla")) == 0);
         QTimer::singleShot(0, &loop, &QEventLoop::quit);

samples/client/petstore/cpp-qt5/PetStore/PetApiTests.cpp

@@ -21,14 +21,34 @@
 #include <QList>
 #include <QMap>
 #include <QSet>
-#include <QVariant>
 
 #include "PFXEnum.h"
 #include "PFXHttpFileElement.h"
 #include "PFXObject.h"
 
 namespace test_namespace {
 
+template <typename T>
+class OptionalParam {
+public:
+    T m_Value;
+    bool m_hasValue;
+public:
+    OptionalParam(){
+        m_hasValue = false;
+    }
+    OptionalParam(const T &val){
+        m_hasValue = true;
+        m_Value = val;
+    }
+    bool hasValue() const {
+        return m_hasValue;
+    }
+    T value() const{
+        return m_Value;
+    }
+};
+
 bool setDateTimeFormat(const QString&);
 
 template <typename T>