Fix QDebug cumulating operator<< with many Q_ENUM

The problem is that the operator<< was taking a non-const reference to the QDebug
object. This causes a problem as all other operator<< return a temporary.
Since every other roperator<< takes the QDebug by value, we should also take it by value
in this case.

Move the operator<< in qdebug.h because i don't want to #include qdebug.h from qobject.h
And move the qt_QMetaEnum_debugOperator to be in the corresponding .cpp

Task-number: QTBUG-44462
Change-Id: Ia01629224c58930c2997e767efc43de90d6309e2
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>

src/corelib/io/qdebug.cpp

@@ -40,6 +40,7 @@
 #endif
 
 #include "qdebug.h"
+#include "qmetaobject.h"
 #include <private/qtextstream_p.h>
 #include <private/qtools_p.h>
 
@@ -643,4 +644,23 @@ QDebugStateSaver::~QDebugStateSaver()
     d->restoreState();
 }
 
+#ifndef QT_NO_QOBJECT
+/*!
+    \internal
+ */
+QDebug qt_QMetaEnum_debugOperator(QDebug &dbg, int value, const QMetaObject *meta, const char *name)
+{
+    QDebugStateSaver saver(dbg);
+    QMetaEnum me = meta->enumerator(meta->indexOfEnumerator(name));
+    const char *key = me.valueToKey(value);
+    dbg.nospace() << meta->className() << "::" << name << '(';
+    if (key)
+        dbg << key;
+    else
+        dbg << value;
+    dbg << ')';
+    return dbg;
+}
+#endif
+
 QT_END_NAMESPACE

src/corelib/io/qdebug.h

@@ -261,6 +261,19 @@ inline QDebug operator<<(QDebug debug, const QContiguousCache<T> &cache)
     return debug.maybeSpace();
 }
 
+#ifndef QT_NO_QOBJECT
+Q_CORE_EXPORT QDebug qt_QMetaEnum_debugOperator(QDebug&, int value, const QMetaObject *meta, const char *name);
+
+template<typename T>
+typename QtPrivate::QEnableIf<QtPrivate::IsQEnumHelper<T>::Value, QDebug>::Type
+operator<<(QDebug dbg, T value)
+{
+    const QMetaObject *obj = qt_getEnumMetaObject(value);
+    const char *name = qt_getEnumName(value);
+    return qt_QMetaEnum_debugOperator(dbg, typename QFlags<T>::Int(value), obj, name);
+}
+#endif
+
 template <class T>
 inline QDebug operator<<(QDebug debug, const QFlags<T> &flags)
 {

src/corelib/kernel/qobject.cpp

@@ -4106,20 +4106,6 @@ QDebug operator<<(QDebug dbg, const QObject *o)
     dbg << ')';
     return dbg;
 }
-
-QDebug qt_QMetaEnum_debugOperator(QDebug &dbg, int value, const QMetaObject *meta, const char *name)
-{
-    QDebugStateSaver saver(dbg);
-    QMetaEnum me = meta->enumerator(meta->indexOfEnumerator(name));
-    const char *key = me.valueToKey(value);
-    dbg.nospace() << meta->className() << "::" << name << '(';
-    if (key)
-        dbg << key;
-    else
-        dbg << value;
-    dbg << ')';
-    return dbg;
-}
 #endif
 
 /*!

src/corelib/kernel/qobject.h

@@ -547,16 +547,6 @@ template <class T> inline const char * qobject_interface_iid()
 
 #ifndef QT_NO_DEBUG_STREAM
 Q_CORE_EXPORT QDebug operator<<(QDebug, const QObject *);
-Q_CORE_EXPORT QDebug qt_QMetaEnum_debugOperator(QDebug&, int value, const QMetaObject *meta, const char *name);
-
-template<typename T>
-typename QtPrivate::QEnableIf<QtPrivate::IsQEnumHelper<T>::Value , QDebug>::Type
-operator<<(QDebug &dbg, T value)
-{
-    const QMetaObject *obj = qt_getEnumMetaObject(value);
-    const char *name = qt_getEnumName(value);
-    return qt_QMetaEnum_debugOperator(dbg, typename QFlags<T>::Int(value), obj, name);
-}
 #endif
 
 class QSignalBlocker

tests/auto/corelib/kernel/qmetaobject/tst_qmetaobject.cpp

@@ -1417,6 +1417,9 @@ void tst_QMetaObject::enumDebugStream()
     QTest::ignoreMessage(QtDebugMsg, "hello MyNamespace::MyClass::MyEnum(MyEnum2) world ");
     MyNamespace::MyClass::MyEnum e = MyNamespace::MyClass::MyEnum2;
     qDebug() << "hello" << e << "world";
+
+    QTest::ignoreMessage(QtDebugMsg, "Qt::WindowType(WindowTitleHint) Qt::WindowType(Window) Qt::WindowType(Desktop) Qt::WindowType(WindowSystemMenuHint)");
+    qDebug() << Qt::WindowTitleHint << Qt::Window <<Qt::Desktop << Qt::WindowSystemMenuHint;
 }
 
 QTEST_MAIN(tst_QMetaObject)