diff --git a/src/corelib/kernel/qeventdispatcher_win.cpp b/src/corelib/kernel/qeventdispatcher_win.cpp index d547642e7dc..28d11d05768 100644 --- a/src/corelib/kernel/qeventdispatcher_win.cpp +++ b/src/corelib/kernel/qeventdispatcher_win.cpp @@ -492,13 +492,17 @@ bool QEventDispatcherWin32::processEvents(QEventLoop::ProcessEventsFlags flags) { Q_D(QEventDispatcherWin32); - d->interrupt.storeRelaxed(false); + // We don't know _when_ the interrupt occurred so we have to honor it. + const bool wasInterrupted = d->interrupt.fetchAndStoreRelaxed(false); emit awake(); // To prevent livelocks, send posted events once per iteration. // QCoreApplication::sendPostedEvents() takes care about recursions. sendPostedEvents(); + if (wasInterrupted) + return false; + auto threadData = d->threadData.loadRelaxed(); bool canWait; bool retVal = false; diff --git a/tests/auto/corelib/kernel/qeventdispatcher/tst_qeventdispatcher.cpp b/tests/auto/corelib/kernel/qeventdispatcher/tst_qeventdispatcher.cpp index fa5c78bcebb..ac71e6b08c0 100644 --- a/tests/auto/corelib/kernel/qeventdispatcher/tst_qeventdispatcher.cpp +++ b/tests/auto/corelib/kernel/qeventdispatcher/tst_qeventdispatcher.cpp @@ -69,6 +69,7 @@ private slots: void processEventsOnlySendsQueuedEvents(); void postedEventsPingPong(); void eventLoopExit(); + void interruptTrampling(); }; bool tst_QEventDispatcher::event(QEvent *e) @@ -419,5 +420,31 @@ void tst_QEventDispatcher::eventLoopExit() QVERIFY(!timeoutObserved); } +// Based on QTBUG-91539: In the event dispatcher on Windows we overwrite the +// interrupt once we start processing events (this pattern is also in the 'unix' dispatcher) +// which would lead the dispatcher to accidentally ignore certain interrupts and, +// as in the bug report, would not quit, leaving the thread alive and running. +void tst_QEventDispatcher::interruptTrampling() +{ + class WorkerThread : public QThread + { + void run() override { + auto dispatcher = eventDispatcher(); + QVERIFY(dispatcher); + dispatcher->processEvents(QEventLoop::AllEvents); + QTimer::singleShot(0, [dispatcher]() { + dispatcher->wakeUp(); + }); + dispatcher->processEvents(QEventLoop::WaitForMoreEvents); + dispatcher->interrupt(); + dispatcher->processEvents(QEventLoop::WaitForMoreEvents); + } + }; + WorkerThread thread; + thread.start(); + QVERIFY(thread.wait(1000)); + QVERIFY(thread.isFinished()); +} + QTEST_MAIN(tst_QEventDispatcher) #include "tst_qeventdispatcher.moc"