Prevent a crash with brushed metal windows and a qApp style sheet

My great metal hack simply needs to hack more and not do the "extra"
assign since I'm doing this through a back door in set attribute. We
probably should have had the brushed metal go via an actual QStyle
subclass instead of through the attribute.

Task-number: 253448
Reviewed-by: ogoffart

1 files changed, 17 insertions, 4 deletions

diff --git a/src/gui/kernel/qwidget.cpp b/src/gui/kernel/qwidget.cpp
index d911b48704..4cb9380e04 100644
--- a/src/gui/kernel/qwidget.cpp
+++ b/src/gui/kernel/qwidget.cpp
@@ -2343,13 +2343,26 @@ void QWidgetPrivate::setStyle_helper(QStyle *newStyle, bool propagate, bool
         )
 {
     Q_Q(QWidget);
-    createExtra();
-
     QStyle *oldStyle  = q->style();
 #ifndef QT_NO_STYLE_STYLESHEET
-    QStyle *origStyle = extra->style;
+    QStyle *origStyle = 0;
+#endif
+
+#ifdef Q_WS_MAC
+    // the metalhack boolean allows Qt/Mac to do a proper re-polish depending
+    // on how the Qt::WA_MacBrushedMetal attribute is set. It is only ever
+    // set when changing that attribute and passes the widget's CURRENT style.
+    // therefore no need to do a reassignment.
+    if (!metalHack)
 #endif
-    extra->style = newStyle;
+    {
+        createExtra();
+
+#ifndef QT_NO_STYLE_STYLESHEET
+        origStyle = extra->style;
+#endif
+        extra->style = newStyle;
+    }
 
     // repolish
     if (q->windowType() != Qt::Desktop) {