Crash in QWidgetPrivate::init on QApplication::quit() using a modal dialog on Mac

The problem was the order of deletion in the destructor. To autotest
this I create an application, start a modal dialog and then quit the
application.
The fix was contributed by a customer.

Task-number: QTBUG-12673
Reviewed-by: Olivier Goffart

7 files changed, 94 insertions, 12 deletions

diff --git a/src/gui/kernel/qapplication.cpp b/src/gui/kernel/qapplication.cpp
index e164baf..3d3a749 100644
--- a/src/gui/kernel/qapplication.cpp
+++ b/src/gui/kernel/qapplication.cpp
@@ -1055,6 +1055,18 @@ QApplication::~QApplication()
     QApplicationPrivate::is_app_closing = true;
     QApplicationPrivate::is_app_running = false;
 
+    // delete all widgets
+    if (QWidgetPrivate::allWidgets) {
+        QWidgetSet *mySet = QWidgetPrivate::allWidgets;
+        QWidgetPrivate::allWidgets = 0;
+        for (QWidgetSet::ConstIterator it = mySet->constBegin(); it != mySet->constEnd(); ++it) {
+            register QWidget *w = *it;
+            if (!w->parent())                        // window
+                w->destroy(true, true);
+        }
+        delete mySet;
+    }
+
     delete qt_desktopWidget;
     qt_desktopWidget = 0;
 
@@ -1075,18 +1087,6 @@ QApplication::~QApplication()
     delete QWidgetPrivate::mapper;
     QWidgetPrivate::mapper = 0;
 
-    // delete all widgets
-    if (QWidgetPrivate::allWidgets) {
-        QWidgetSet *mySet = QWidgetPrivate::allWidgets;
-        QWidgetPrivate::allWidgets = 0;
-        for (QWidgetSet::ConstIterator it = mySet->constBegin(); it != mySet->constEnd(); ++it) {
-            register QWidget *w = *it;
-            if (!w->parent())                        // window
-                w->destroy(true, true);
-        }
-        delete mySet;
-    }
-
     delete QApplicationPrivate::app_pal;
     QApplicationPrivate::app_pal = 0;
     delete QApplicationPrivate::sys_pal;
diff --git a/tests/auto/qapplication/modal/base.cpp b/tests/auto/qapplication/modal/base.cpp
new file mode 100644
index 0000000..d3a7de6
--- /dev/null
+++ b/tests/auto/qapplication/modal/base.cpp
@@ -0,0 +1,21 @@
+#include "base.h"
+
+base::base(QWidget *parent) :
+    QWidget(parent)
+{
+    m_timer = new QTimer(this);
+    m_modalStarted = false;
+    m_timer->setSingleShot(false);
+    connect(m_timer, SIGNAL(timeout()), this, SLOT(periodicTimer()));
+    m_timer->start(5000);
+}
+
+void base::periodicTimer()
+{
+    if(m_modalStarted)
+        exit(0);
+    m_modalDialog = new QDialog(this);
+    m_modalDialog->setModal(true);
+    m_modalDialog->show();
+    m_modalStarted = true;
+}
diff --git a/tests/auto/qapplication/modal/base.h b/tests/auto/qapplication/modal/base.h
new file mode 100644
index 0000000..ebf1198
--- /dev/null
+++ b/tests/auto/qapplication/modal/base.h
@@ -0,0 +1,23 @@
+#ifndef BASE_H
+#define BASE_H
+
+#include <QWidget>
+#include <QTimer>
+#include <QDialog>
+
+class base : public QWidget
+{
+Q_OBJECT
+    QTimer *m_timer;
+    bool m_modalStarted;
+    QDialog *m_modalDialog;
+public:
+    explicit base(QWidget *parent = 0);
+
+signals:
+
+public slots:
+    void periodicTimer();
+};
+
+#endif // BASE_H
diff --git a/tests/auto/qapplication/modal/main.cpp b/tests/auto/qapplication/modal/main.cpp
new file mode 100644
index 0000000..e1d39cf
--- /dev/null
+++ b/tests/auto/qapplication/modal/main.cpp
@@ -0,0 +1,11 @@
+#include <QtGui>
+
+#include <QApplication>
+#include "base.h"
+
+int main(int argc, char *argv[])
+{
+    QApplication app(argc, argv);
+    base *b = new base();
+    return app.exec();
+}
diff --git a/tests/auto/qapplication/modal/modal.pro b/tests/auto/qapplication/modal/modal.pro
new file mode 100644
index 0000000..836f6ff
--- /dev/null
+++ b/tests/auto/qapplication/modal/modal.pro
@@ -0,0 +1,8 @@
+TEMPLATE = app
+TARGET = 
+DEPENDPATH += .
+INCLUDEPATH += .
+SOURCES += main.cpp \
+    base.cpp
+DESTDIR = ./
+HEADERS += base.h
diff --git a/tests/auto/qapplication/qapplication.pro b/tests/auto/qapplication/qapplication.pro
index 7814ad3..becc6c6 100644
--- a/tests/auto/qapplication/qapplication.pro
+++ b/tests/auto/qapplication/qapplication.pro
@@ -1,6 +1,7 @@
 TEMPLATE = subdirs
 SUBDIRS = test \
 	  desktopsettingsaware \
+          modal \
       wincmdline
 
 
diff --git a/tests/auto/qapplication/tst_qapplication.cpp b/tests/auto/qapplication/tst_qapplication.cpp
index 1a38070..91ae921 100644
--- a/tests/auto/qapplication/tst_qapplication.cpp
+++ b/tests/auto/qapplication/tst_qapplication.cpp
@@ -146,6 +146,7 @@ private slots:
 
     void symbianNeedForTraps();
     void symbianLeaveThroughMain();
+    void qtbug_12673();
 };
 
 class EventSpy : public QObject
@@ -2239,6 +2240,23 @@ void tst_QApplication::symbianLeaveThroughMain()
 #endif
 }
 
+void tst_QApplication::qtbug_12673()
+{
+#ifdef Q_OS_SYMBIAN
+    QSKIP("This might not make sense in Symbian, but since I do not know how to test it I'll just skip it for now.", SkipAll);
+#else
+    QProcess testProcess;
+    QStringList arguments;
+#ifdef Q_OS_MAC
+    testProcess.start("modal/modal.app", arguments);
+#else
+    testProcess.start("modal/modal", arguments);
+#endif
+    QVERIFY(testProcess.waitForFinished(20000));
+    QCOMPARE(testProcess.exitStatus(), QProcess::NormalExit);
+#endif //  Q_OS_SYMBIAN
+}
+
 //QTEST_APPLESS_MAIN(tst_QApplication)
 int main(int argc, char *argv[])
 {