QDialogButtonGroup: Fix removal of deleted buttons

As the destroyed() signal is emitted from ~QObject, it is not allowed
to use static_cast to a QAbstractButton on that pointer anymore.
And the qobject_cast will also fail which will keep a dangling pointer
in the hash.

Change-Id: If0d22fcc30cde87e771e70914c3afb04ea207289
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

2 files changed, 21 insertions, 3 deletions

diff --git a/src/widgets/widgets/qdialogbuttonbox.cpp b/src/widgets/widgets/qdialogbuttonbox.cpp
index 23158cf82f..984669f29a 100644
--- a/src/widgets/widgets/qdialogbuttonbox.cpp
+++ b/src/widgets/widgets/qdialogbuttonbox.cpp
@@ -716,8 +716,7 @@ void QDialogButtonBox::removeButton(QAbstractButton *button)
         return;
 
     // Remove it from the standard button hash first and then from the roles
-    if (QPushButton *pushButton = qobject_cast<QPushButton *>(button))
-        d->standardButtonHash.remove(pushButton);
+    d->standardButtonHash.remove(reinterpret_cast<QPushButton *>(button));
     for (int i = 0; i < NRoles; ++i) {
         QList<QAbstractButton *> &list = d->buttonLists[i];
         for (int j = 0; j < list.count(); ++j) {
@@ -883,7 +882,7 @@ void QDialogButtonBoxPrivate::_q_handleButtonDestroyed()
     Q_Q(QDialogButtonBox);
     if (QObject *object = q->sender()) {
         QBoolBlocker skippy(internalRemove);
-        q->removeButton(static_cast<QAbstractButton *>(object));
+        q->removeButton(reinterpret_cast<QAbstractButton *>(object));
     }
 }
 
diff --git a/tests/auto/widgets/widgets/qdialogbuttonbox/tst_qdialogbuttonbox.cpp b/tests/auto/widgets/widgets/qdialogbuttonbox/tst_qdialogbuttonbox.cpp
index a35ea8eb6e..f127fd98f7 100644
--- a/tests/auto/widgets/widgets/qdialogbuttonbox/tst_qdialogbuttonbox.cpp
+++ b/tests/auto/widgets/widgets/qdialogbuttonbox/tst_qdialogbuttonbox.cpp
@@ -97,6 +97,8 @@ private slots:
     void testDefaultButton();
 
     void task191642_default();
+    void testDeletedStandardButton();
+
 private:
     qint64 timeStamp;
     qint64 buttonClicked1TimeStamp;
@@ -843,5 +845,22 @@ void tst_QDialogButtonBox::task191642_default()
     QCOMPARE(clicked.count(), 1);
 }
 
+void tst_QDialogButtonBox::testDeletedStandardButton()
+{
+    QDialogButtonBox buttonBox;
+    delete buttonBox.addButton(QDialogButtonBox::Ok);
+    QPointer<QPushButton> buttonC = buttonBox.addButton(QDialogButtonBox::Cancel);
+    delete buttonBox.addButton(QDialogButtonBox::Cancel);
+    QPointer<QPushButton> buttonA = buttonBox.addButton(QDialogButtonBox::Apply);
+    delete buttonBox.addButton(QDialogButtonBox::Help);
+    // A few button have been deleted, they should automatically be removed
+    QCOMPARE(buttonBox.standardButtons(), QDialogButtonBox::Apply | QDialogButtonBox::Cancel);
+
+    buttonBox.setStandardButtons(QDialogButtonBox::Reset | QDialogButtonBox::Cancel);
+    // setStanderdButton should delete previous buttons
+    QVERIFY(!buttonA);
+    QVERIFY(!buttonC);
+}
+
 QTEST_MAIN(tst_QDialogButtonBox)
 #include "tst_qdialogbuttonbox.moc"