QItemSelectionModelPrivate: use QObjectPrivate::connect

QItemSelectionModelPrivate::initModel() uses string based connections,
to connect/disconnet its QAbstractItemModel.
The QObject::destroyed signal is connected to modelDestroyed(), which
does not disconnect other signals.

QQuickTableView's selection model binds to its QAbstractItemModel.
The binding also reacts to QObject::destroyed
Eventually, QItemSelectionModel::setModel(nullptr) is called.
At this point, only a QOBject is left from the QAbstractItemModel.
That leads to warnings about disconnecting string based signals, which
belong to QAbstractItemModel.

This patch changes the connect syntax to the QObjectPrivate::connect
API. Instead of keeping a list of string based connections around, the
connections themselves are kept in a list member. Disconnecting happens
based on that list.
Connections are also disconnected in
QAbstractItemModelPrivate::modelDestroyed.

An auto test is added in tst_QItemSelectionModel.

Fixes: QTBUG-116056
Pick-to: 6.6 6.5 6.2
Change-Id: I57e5c0f0a574f154eb312a282003774dd0613dd6
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 35 insertions, 0 deletions

diff --git a/tests/auto/corelib/itemmodels/qitemselectionmodel/tst_qitemselectionmodel.cpp b/tests/auto/corelib/itemmodels/qitemselectionmodel/tst_qitemselectionmodel.cpp
index 2d09b01c26..a14336e119 100644
--- a/tests/auto/corelib/itemmodels/qitemselectionmodel/tst_qitemselectionmodel.cpp
+++ b/tests/auto/corelib/itemmodels/qitemselectionmodel/tst_qitemselectionmodel.cpp
@@ -80,7 +80,10 @@ private slots:
 
     void QTBUG93305();
 
+    void testSignalsDisconnection();
+
 private:
+    static void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg);
     QAbstractItemModel *model;
     QItemSelectionModel *selection;
 };
@@ -2917,5 +2920,37 @@ void tst_QItemSelectionModel::QTBUG93305()
     QCOMPARE(spy.size(), 4);
 }
 
+static void (*oldMessageHandler)(QtMsgType, const QMessageLogContext&, const QString&);
+static bool signalError = false;
+
+// detect disconnect warning:
+// qt.core.qobject.connect: QObject::disconnect: No such signal
+void tst_QItemSelectionModel::messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg)
+{
+    Q_ASSERT(oldMessageHandler);
+
+    if (type == QtWarningMsg
+            && QString(context.category) == "qt.core.qobject.connect"
+            && msg.contains("No such")) {
+        signalError = true;
+    }
+
+    return oldMessageHandler(type, context, msg);
+}
+
+void tst_QItemSelectionModel::testSignalsDisconnection()
+{
+    oldMessageHandler = qInstallMessageHandler(messageHandler);
+    auto resetMessageHandler = qScopeGuard([] { qInstallMessageHandler(oldMessageHandler); });
+    auto *newModel = new QStandardItemModel(model);
+    selection->setModel(newModel);
+    QSignalSpy spy(newModel, &QObject::destroyed);
+    delete newModel;
+    QTRY_COMPARE(spy.count(), 1);
+    qDebug() << spy;
+    selection->setModel(nullptr);
+    QVERIFY(!signalError);
+}
+
 QTEST_MAIN(tst_QItemSelectionModel)
 #include "tst_qitemselectionmodel.moc"