QDialogButtonBox: properly clear buttons in setStandardButtons()HEADdev

When setting new buttons with setStandardButtons(), the old ones are
deleted by iterating over d->standardButtonHash. But this hash is
modified when a button is destroyed and therefore sometimes not all
buttons were deleted.
This amends df735d794fd2e545c18b9e345e833422bcd64329.

Fixes: QTBUG-123939
Pick-to: 6.7 6.5
Change-Id: I867086855cfde88a7b22a5579662f250b9db0042
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/widgets/widgets/qdialogbuttonbox.cpp b/src/widgets/widgets/qdialogbuttonbox.cpp
index 30ace89fa8..30c68ad18b 100644
--- a/src/widgets/widgets/qdialogbuttonbox.cpp
+++ b/src/widgets/widgets/qdialogbuttonbox.cpp
@@ -647,12 +647,12 @@ void QDialogButtonBox::clear()
     d->standardButtonHash.clear();
     for (int i = 0; i < NRoles; ++i) {
         QList<QAbstractButton *> &list = d->buttonLists[i];
-        while (list.size()) {
-            QAbstractButton *button = list.takeAt(0);
+        for (auto button : std::as_const(list)) {
             QObjectPrivate::disconnect(button, &QAbstractButton::destroyed,
                                        d, &QDialogButtonBoxPrivate::handleButtonDestroyed);
             delete button;
         }
+        list.clear();
     }
 }
 
@@ -818,8 +818,8 @@ void QDialogButtonBox::setStandardButtons(StandardButtons buttons)
 {
     Q_D(QDialogButtonBox);
     // Clear out all the old standard buttons, then recreate them.
-    qDeleteAll(d->standardButtonHash.keyBegin(), d->standardButtonHash.keyEnd());
-    d->standardButtonHash.clear();
+    const auto toDelete = std::exchange(d->standardButtonHash, {});
+    qDeleteAll(toDelete.keyBegin(), toDelete.keyEnd());
 
     d->createStandardButtons(buttons);
 }