QEventDispatcherWin32: retrieve PM_REMOVE value as a bit flag

Windows unexpectedly passes PM_NOYIELD flag in wParam parameter to the
hook procedure, if ::PeekMessage(..., PM_REMOVE | PM_NOYIELD) is called
from the event loop. So, to ignore undocumented flag, we should
interpret wParam as a bit field.

Thanks to Robin Lobel for research.

Fixes: QTBUG-84562
Change-Id: Ib16d7d747aebc9a3628e4ee67478c4d3edeb96f1
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
(cherry picked from commit 33e6e5fac3c86805b1b4e744462645cac8c8a044)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/tests/auto/gui/kernel/noqteventloop/tst_noqteventloop.cpp b/tests/auto/gui/kernel/noqteventloop/tst_noqteventloop.cpp
index 3d1876f00f..5fd7079a6a 100644
--- a/tests/auto/gui/kernel/noqteventloop/tst_noqteventloop.cpp
+++ b/tests/auto/gui/kernel/noqteventloop/tst_noqteventloop.cpp
@@ -51,6 +51,7 @@ private slots:
     void consumeMouseEvents();
     void consumeSocketEvents();
     void deliverEventsInLivelock();
+    void postingWithNoYieldFlag();
 };
 
 class Window : public QRasterWindow
@@ -341,6 +342,43 @@ void tst_NoQtEventLoop::deliverEventsInLivelock()
     QVERIFY(!livelockTimer.isActive());
 }
 
+void tst_NoQtEventLoop::postingWithNoYieldFlag()
+{
+    int argc = 1;
+    char *argv[] = { const_cast<char *>("test"), 0 };
+    QGuiApplication app(argc, argv);
+
+    bool signalReceived = false;
+    // Post a message to the queue
+    QMetaObject::invokeMethod(this, [&signalReceived]() {
+        signalReceived = true;
+    }, Qt::QueuedConnection);
+
+    // Post some system messages
+    QWindow mainWindow;
+    mainWindow.show();
+
+    QElapsedTimer elapsedTimer;
+    elapsedTimer.start();
+
+    // Exec own message loop
+    MSG msg;
+    forever {
+        if (elapsedTimer.hasExpired(3000) || signalReceived)
+            break;
+
+        if (!::PeekMessage(&msg, NULL, 0, 0, PM_REMOVE | PM_NOYIELD)) {
+            QThread::msleep(100);
+            continue;
+        }
+
+        ::TranslateMessage(&msg);
+        ::DispatchMessage(&msg);
+    }
+
+    QVERIFY(signalReceived);
+}
+
 #include <tst_noqteventloop.moc>
 
 QTEST_APPLESS_MAIN(tst_NoQtEventLoop)