Replace QString::null/isNull() by QString()/isEmpty()

Fix warnings appearing in Qt 5.13:
sources/shiboken2/generator/shiboken2/shibokengenerator.cpp:873:25: warning: ‘QString::null’ is deprecated: use QString() [-Wdeprecated-declarations]
sources/shiboken2/generator/shiboken2/shibokengenerator.cpp:873:25: warning: ‘QString::null’ is deprecated: use QString() [-Wdeprecated-declarations]
sources/shiboken2/generator/shiboken2/shibokengenerator.cpp:880:25: warning: ‘QString::null’ is deprecated: use QString() [-Wdeprecated-declarations]
sources/shiboken2/generator/shiboken2/shibokengenerator.cpp:880:25: warning: ‘QString::null’ is deprecated: use QString() [-Wdeprecated-declarations]
sources/shiboken2/generator/shiboken2/cppgenerator.cpp:5060:34: warning: ‘QString::null’ is deprecated: use QString() [-Wdeprecated-declarations]
sources/shiboken2/generator/shiboken2/cppgenerator.cpp:5060:34: warning: ‘QString::null’ is deprecated: use QString() [-Wdeprecated-declarations]

Change-Id: I7c938df64babf824b58bf5c785b281a88d5111db
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

6 files changed, 13 insertions, 13 deletions

diff --git a/sources/shiboken2/ApiExtractor/abstractmetalang.cpp b/sources/shiboken2/ApiExtractor/abstractmetalang.cpp
index c3063aaa1..73f1bf621 100644
--- a/sources/shiboken2/ApiExtractor/abstractmetalang.cpp
+++ b/sources/shiboken2/ApiExtractor/abstractmetalang.cpp
@@ -156,7 +156,7 @@ static QString lastNameSegment(QString name)
 
 QString AbstractMetaType::name() const
 {
-    if (m_name.isNull())
+    if (m_name.isEmpty())
         m_name = lastNameSegment(m_typeEntry->targetLangName());
     return m_name;
 }
diff --git a/sources/shiboken2/ApiExtractor/tests/testtemplates.cpp b/sources/shiboken2/ApiExtractor/tests/testtemplates.cpp
index b1b171bae..59b601f3b 100644
--- a/sources/shiboken2/ApiExtractor/tests/testtemplates.cpp
+++ b/sources/shiboken2/ApiExtractor/tests/testtemplates.cpp
@@ -111,7 +111,7 @@ namespace Namespace {
     AbstractMetaClass* classB = AbstractMetaClass::findClass(classes, QLatin1String("B"));
     QVERIFY(classB);
     QVERIFY(!classB->baseClass());
-    QVERIFY(classB->baseClassName().isNull());
+    QVERIFY(classB->baseClassName().isEmpty());
     const AbstractMetaFunction* func = classB->findFunction(QLatin1String("foo"));
     AbstractMetaType* argType = func->arguments().first()->type();
     QCOMPARE(argType->instantiations().count(), 1);
@@ -300,7 +300,7 @@ template<SomeEnum type> struct Future {};
     AbstractMetaClass* classB = AbstractMetaClass::findClass(classes, QLatin1String("B"));
     QVERIFY(classB);
     QVERIFY(!classB->baseClass());
-    QVERIFY(classB->baseClassName().isNull());
+    QVERIFY(classB->baseClassName().isEmpty());
     // 3 functions: simple constructor, copy constructor and "method()".
     QCOMPARE(classB->functions().count(), 3);
 }
@@ -338,7 +338,7 @@ template<SomeEnum type> struct Future {};
     AbstractMetaClass* classB = AbstractMetaClass::findClass(classes, QLatin1String("Namespace::B"));
     QVERIFY(classB);
     QVERIFY(!classB->baseClass());
-    QVERIFY(classB->baseClassName().isNull());
+    QVERIFY(classB->baseClassName().isEmpty());
     // 3 functions: simple constructor, copy constructor and "method()".
     QCOMPARE(classB->functions().count(), 3);
 }
diff --git a/sources/shiboken2/generator/main.cpp b/sources/shiboken2/generator/main.cpp
index c5bcb766d..9cdc77ca7 100644
--- a/sources/shiboken2/generator/main.cpp
+++ b/sources/shiboken2/generator/main.cpp
@@ -171,7 +171,7 @@ static CommandArgumentMap getInitializedArguments()
         }
     }
 
-    if (projectFileName.isNull())
+    if (projectFileName.isEmpty())
         return args;
 
     if (!QFile::exists(projectFileName)) {
diff --git a/sources/shiboken2/generator/qtdoc/qtdocgenerator.cpp b/sources/shiboken2/generator/qtdoc/qtdocgenerator.cpp
index b8ef2b052..c194c0ea4 100644
--- a/sources/shiboken2/generator/qtdoc/qtdocgenerator.cpp
+++ b/sources/shiboken2/generator/qtdoc/qtdocgenerator.cpp
@@ -756,11 +756,11 @@ void QtXmlToSphinx::handleSnippetTag(QXmlStreamReader& reader)
         // Fall back to C++ snippet when "path" attribute is present.
         // Also read fallback snippet when comparison is desired.
         QString fallbackCode;
-        if ((pythonCode.isNull() || snippetComparison())
+        if ((pythonCode.isEmpty() || snippetComparison())
             && reader.attributes().hasAttribute(fallbackPathAttribute())) {
             const QString fallback = reader.attributes().value(fallbackPathAttribute()).toString();
             if (QFileInfo::exists(fallback)) {
-                if (pythonCode.isNull())
+                if (pythonCode.isEmpty())
                     qCWarning(lcShiboken, "%s", qPrintable(msgFallbackWarning(reader, m_context, m_lastTagName, location, identifier, fallback)));
                 fallbackCode = readFromLocation(fallback, identifier, &errorMessage);
                 if (!errorMessage.isEmpty())
@@ -775,7 +775,7 @@ void QtXmlToSphinx::handleSnippetTag(QXmlStreamReader& reader)
             m_output << INDENT << "::\n\n";
 
         Indentation indentation(INDENT);
-        const QString code = pythonCode.isNull() ? fallbackCode : pythonCode;
+        const QString code = pythonCode.isEmpty() ? fallbackCode : pythonCode;
         if (code.isEmpty())
             m_output << INDENT << "<Code snippet \"" << location << ':' << identifier << "\" not found>" << endl;
         else
diff --git a/sources/shiboken2/generator/shiboken2/cppgenerator.cpp b/sources/shiboken2/generator/shiboken2/cppgenerator.cpp
index 0ca0b8d04..20030bcdf 100644
--- a/sources/shiboken2/generator/shiboken2/cppgenerator.cpp
+++ b/sources/shiboken2/generator/shiboken2/cppgenerator.cpp
@@ -5067,7 +5067,7 @@ void CppGenerator::writeClassRegister(QTextStream &s,
     for (AbstractMetaClass *innerClass : innerClasses)
         lookForEnumsInClassesNotToBeGenerated(classEnums, innerClass);
 
-    ErrorCode errorCode(QString::null);
+    ErrorCode errorCode(QString::fromLatin1(""));
     writeEnumsInitialization(s, classEnums);
 
     if (metaClass->hasSignals())
diff --git a/sources/shiboken2/generator/shiboken2/shibokengenerator.cpp b/sources/shiboken2/generator/shiboken2/shibokengenerator.cpp
index a226f2c00..ca5dab54e 100644
--- a/sources/shiboken2/generator/shiboken2/shibokengenerator.cpp
+++ b/sources/shiboken2/generator/shiboken2/shibokengenerator.cpp
@@ -870,14 +870,14 @@ QString ShibokenGenerator::converterObject(const TypeEntry* type)
 
     if (type->isArray()) {
         qDebug() << "Warning: no idea how to handle the Qt5 type " << type->qualifiedCppName();
-        return QString::null;
+        return QString();
     }
 
     /* the typedef'd primitive types case */
     const PrimitiveTypeEntry* pte = dynamic_cast<const PrimitiveTypeEntry*>(type);
     if (!pte) {
         qDebug() << "Warning: the Qt5 primitive type is unknown" << type->qualifiedCppName();
-        return QString::null;
+        return QString();
     }
     if (pte->basicReferencedTypeEntry())
         pte = pte->basicReferencedTypeEntry();
@@ -1457,7 +1457,7 @@ void ShibokenGenerator::writeFunctionArguments(QTextStream &s,
 QString ShibokenGenerator::functionReturnType(const AbstractMetaFunction* func, Options options) const
 {
     QString modifiedReturnType = QString(func->typeReplaced(0));
-    if (!modifiedReturnType.isNull() && !(options & OriginalTypeDescription))
+    if (!modifiedReturnType.isEmpty() && !(options & OriginalTypeDescription))
         return modifiedReturnType;
     return translateType(func->type(), func->implementingClass(), options);
 }
@@ -1821,7 +1821,7 @@ void ShibokenGenerator::writeCodeSnips(QTextStream& s,
 
         if (func->isVirtual() && !func->isAbstract() && (!avoidProtectedHack() || !func->isProtected())) {
             QString methodCallArgs = getArgumentsFromMethodCall(code);
-            if (!methodCallArgs.isNull()) {
+            if (!methodCallArgs.isEmpty()) {
                 const QString pattern = QStringLiteral("%CPPSELF.%FUNCTION_NAME(%1)").arg(methodCallArgs);
                 if (func->name() == QLatin1String("metaObject")) {
                     QString wrapperClassName = wrapperName(func->ownerClass());