Make sure that signal disconnects don't disconnect too much

There has been a latent bug forever in QtDBus that would make a signal
disconnect actually disconnect too much. The reason is that
disconnectNotify() is called every time a signal is disconnected from
a receiver, but that doesn't mean it was the last connection.

This test checks whether disconnecting from voidSignal() to our test
receiver will also disconnect from exitLoop(). If it does, we'll get a
timeout. I could have implemented it with two receivers, but in the
buggy case, it would always fail first in the timeout verification.

Change-Id: I5766d8a38594eb25e65b304913251303660fad41
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>

1 files changed, 90 insertions, 0 deletions

diff --git a/tests/auto/dbus/qdbusabstractinterface/tst_qdbusabstractinterface.cpp b/tests/auto/dbus/qdbusabstractinterface/tst_qdbusabstractinterface.cpp
index 89b91558ff..786592d018 100644
--- a/tests/auto/dbus/qdbusabstractinterface/tst_qdbusabstractinterface.cpp
+++ b/tests/auto/dbus/qdbusabstractinterface/tst_qdbusabstractinterface.cpp
@@ -159,6 +159,11 @@ private slots:
 
     void followSignal();
 
+    void connectDisconnect_data();
+    void connectDisconnect();
+    void connectDisconnectPeer_data();
+    void connectDisconnectPeer();
+
     void createErrors_data();
     void createErrors();
 
@@ -196,6 +201,15 @@ private:
     QProcess proc;
 };
 
+class SignalReceiver : public QObject
+{
+    Q_OBJECT
+public:
+    int callCount;
+    SignalReceiver() : callCount(0) {}
+public slots:
+    void receive() { ++callCount; }
+};
 
 tst_QDBusAbstractInterface::tst_QDBusAbstractInterface()
 {
@@ -1022,6 +1036,82 @@ void tst_QDBusAbstractInterface::followSignal()
     con.interface()->unregisterService(serviceToFollow);
 }
 
+void tst_QDBusAbstractInterface::connectDisconnect_data()
+{
+    QTest::addColumn<int>("connectCount");
+    QTest::addColumn<int>("disconnectCount");
+
+    // we don't actually need multiple disconnects
+    // QObject::disconnect() disconnects all matching rules
+    // we'd have to use QMetaObject::disconnectOne if we wanted just one
+    QTest::newRow("null") << 0 << 0;
+    QTest::newRow("connect-disconnect") << 1 << 1;
+    QTest::newRow("connect-twice") << 2 << 0;
+    QTest::newRow("connect-twice-disconnect") << 2 << 1;
+}
+
+void tst_QDBusAbstractInterface::connectDisconnect()
+{
+    QFETCH(int, connectCount);
+    QFETCH(int, disconnectCount);
+
+    Pinger p = getPinger();
+    QVERIFY2(p, "Not connected to D-Bus");
+
+    // connect the exitLoop slot first
+    // if the disconnect() below does something weird, we'll get a timeout
+    QTestEventLoop::instance().connect(p.data(), SIGNAL(voidSignal()), SLOT(exitLoop()));
+
+    SignalReceiver sr;
+    for (int i = 0; i < connectCount; ++i)
+        sr.connect(p.data(), SIGNAL(voidSignal()), SLOT(receive()));
+    if (disconnectCount)
+        QObject::disconnect(p.data(), SIGNAL(voidSignal()), &sr, SLOT(receive()));
+
+    emit targetObj.voidSignal();
+    QTestEventLoop::instance().enterLoop(2);
+    QVERIFY(!QTestEventLoop::instance().timeout());
+
+    if (disconnectCount != 0)
+        QCOMPARE(sr.callCount, 0);
+    else
+        QCOMPARE(sr.callCount, connectCount);
+}
+
+void tst_QDBusAbstractInterface::connectDisconnectPeer_data()
+{
+    connectDisconnect_data();
+}
+
+void tst_QDBusAbstractInterface::connectDisconnectPeer()
+{
+    QFETCH(int, connectCount);
+    QFETCH(int, disconnectCount);
+
+    Pinger p = getPingerPeer();
+    QVERIFY2(p, "Not connected to D-Bus");
+
+    // connect the exitLoop slot first
+    // if the disconnect() below does something weird, we'll get a timeout
+    QTestEventLoop::instance().connect(p.data(), SIGNAL(voidSignal()), SLOT(exitLoop()));
+
+    SignalReceiver sr;
+    for (int i = 0; i < connectCount; ++i)
+        sr.connect(p.data(), SIGNAL(voidSignal()), SLOT(receive()));
+    if (disconnectCount)
+        QObject::disconnect(p.data(), SIGNAL(voidSignal()), &sr, SLOT(receive()));
+
+    QDBusMessage req = QDBusMessage::createMethodCall(serviceName, objectPath, interfaceName, "voidSignal");
+    QVERIFY(QDBusConnection::sessionBus().send(req));
+    QTestEventLoop::instance().enterLoop(2);
+    QVERIFY(!QTestEventLoop::instance().timeout());
+
+    if (disconnectCount != 0)
+        QCOMPARE(sr.callCount, 0);
+    else
+        QCOMPARE(sr.callCount, connectCount);
+}
+
 void tst_QDBusAbstractInterface::createErrors_data()
 {
     QTest::addColumn<QString>("service");