From e2331c6f76bda6d19f3b4cb2b9e3cbbfe0bdc2f6 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@kdab.com>
Date: Tue, 29 Jul 2014 15:31:44 +0200
Subject: QProgressDialog: don't crash when setting the same {bar,button,label}
 again

The associated test has unearthed that setBar() fails to make the new bar a child
of the progress dialog. This will be fixed in a separate commit.

Task-number: QTBUG-40502
Change-Id: I2d09ebb07ae6395449a4efe38a638df831eebdd7
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: David Faure <david.faure@kdab.com>
---
 src/widgets/dialogs/qprogressdialog.cpp            | 14 ++++++
 .../qprogressdialog/tst_qprogressdialog.cpp        | 50 ++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/src/widgets/dialogs/qprogressdialog.cpp b/src/widgets/dialogs/qprogressdialog.cpp
index 7a88e65b3c..b514b75324 100644
--- a/src/widgets/dialogs/qprogressdialog.cpp
+++ b/src/widgets/dialogs/qprogressdialog.cpp
@@ -354,6 +354,11 @@ QProgressDialog::~QProgressDialog()
 void QProgressDialog::setLabel(QLabel *label)
 {
     Q_D(QProgressDialog);
+    if (label == d->label) {
+        if (label)
+            qWarning("QProgressDialog::setLabel: Attempt to set the same label again");
+        return;
+    }
     delete d->label;
     d->label = label;
     if (label) {
@@ -411,6 +416,11 @@ void QProgressDialog::setLabelText(const QString &text)
 void QProgressDialog::setCancelButton(QPushButton *cancelButton)
 {
     Q_D(QProgressDialog);
+    if (d->cancel == cancelButton) {
+        if (cancelButton)
+            qWarning("QProgressDialog::setCancelButton: Attempt to set the same button again");
+        return;
+    }
     delete d->cancel;
     d->cancel = cancelButton;
     if (cancelButton) {
@@ -483,6 +493,10 @@ void QProgressDialog::setBar(QProgressBar *bar)
         qWarning("QProgressDialog::setBar: Cannot set a new progress bar "
                   "while the old one is active");
 #endif
+    if (bar == d->bar) {
+        qWarning("QProgressDialog::setBar: Attempt to set the same progress bar again");
+        return;
+    }
     delete d->bar;
     d->bar = bar;
     int w = qMax(isVisible() ? width() : 0, sizeHint().width());
diff --git a/tests/auto/widgets/dialogs/qprogressdialog/tst_qprogressdialog.cpp b/tests/auto/widgets/dialogs/qprogressdialog/tst_qprogressdialog.cpp
index aadc95e640..4ff158f632 100644
--- a/tests/auto/widgets/dialogs/qprogressdialog/tst_qprogressdialog.cpp
+++ b/tests/auto/widgets/dialogs/qprogressdialog/tst_qprogressdialog.cpp
@@ -44,8 +44,11 @@
 
 #include <qapplication.h>
 #include <qdebug.h>
+#include <qprogressbar.h>
 #include <qprogressdialog.h>
+#include <qpushbutton.h>
 #include <qlabel.h>
+#include <qpointer.h>
 #include <qthread.h>
 
 class tst_QProgressDialog : public QObject
@@ -59,6 +62,7 @@ private Q_SLOTS:
     void getSetCheck();
     void task198202();
     void QTBUG_31046();
+    void settingCustomWidgets();
 };
 
 void tst_QProgressDialog::cleanup()
@@ -184,5 +188,51 @@ void tst_QProgressDialog::QTBUG_31046()
     QCOMPARE(50, dlg.value());
 }
 
+void tst_QProgressDialog::settingCustomWidgets()
+{
+    QPointer<QLabel> l = new QLabel;
+    QPointer<QPushButton> btn = new QPushButton;
+    QPointer<QProgressBar> bar = new QProgressBar;
+    QVERIFY(!l->parent());
+    QVERIFY(!btn->parent());
+    QVERIFY(!bar->parent());
+
+    {
+        QProgressDialog dlg;
+
+        QVERIFY(!dlg.isAncestorOf(l));
+        dlg.setLabel(l);
+        QVERIFY(dlg.isAncestorOf(l));
+        QTest::ignoreMessage(QtWarningMsg, "QProgressDialog::setLabel: Attempt to set the same label again");
+        dlg.setLabel(l);          // setting the same widget again should not crash
+        QVERIFY(l);               // and not delete the (old == new) widget
+
+        QVERIFY(!dlg.isAncestorOf(btn));
+        dlg.setCancelButton(btn);
+        QVERIFY(dlg.isAncestorOf(btn));
+        QTest::ignoreMessage(QtWarningMsg, "QProgressDialog::setCancelButton: Attempt to set the same button again");
+        dlg.setCancelButton(btn); // setting the same widget again should not crash
+        QVERIFY(btn);             // and not delete the (old == new) widget
+
+        QVERIFY(!dlg.isAncestorOf(bar));
+        dlg.setBar(bar);
+        QEXPECT_FAIL("", "QProgressBar doesn't adopt custom progress bar as children", Continue);
+        QVERIFY(dlg.isAncestorOf(bar));
+        QTest::ignoreMessage(QtWarningMsg, "QProgressDialog::setBar: Attempt to set the same progress bar again");
+        dlg.setBar(bar);          // setting the same widget again should not crash
+        QVERIFY(bar);             // and not delete the (old == new) widget
+    }
+
+    QVERIFY(!l);
+    QVERIFY(!btn);
+#if 0
+    QEXPECT_FAIL("", "QProgressBar doesn't clean up custom progress bars", Continue);
+    QVERIFY(!bar);
+#else
+    // make cleanup() pass
+    delete bar;
+#endif
+}
+
 QTEST_MAIN(tst_QProgressDialog)
 #include "tst_qprogressdialog.moc"
-- 
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