From 345be581007c05164052e27f90fcfaf27a41c743 Mon Sep 17 00:00:00 2001
From: Jesus Fernandez <jesus.fernandez@qt.io>
Date: Wed, 6 Dec 2017 19:46:31 +0100
Subject: Fix assert when emitting a signal from a different thread

If a signal is emitted more than once in a multithreaded application the
QSignalEventGenerator::execute function asserts in the check for a valid
signal index. It happens after abandoning the state and all the
connections are disconnected. If we have pending signal to be
processed the QObject::sender() won't be able to resolve the sender
object.

Task-number: QTBUG-61463
Change-Id: I9d4b7266c6dddc9ff2e7453b05a6989876ccb332
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
---
 .../qstatemachine/tst_qstatemachine.cpp            | 32 ++++++++++++++++++++++
 1 file changed, 32 insertions(+)

(limited to 'tests/auto/corelib/statemachine')

diff --git a/tests/auto/corelib/statemachine/qstatemachine/tst_qstatemachine.cpp b/tests/auto/corelib/statemachine/qstatemachine/tst_qstatemachine.cpp
index 8f0d83ce32..7ea467b6ef 100644
--- a/tests/auto/corelib/statemachine/qstatemachine/tst_qstatemachine.cpp
+++ b/tests/auto/corelib/statemachine/qstatemachine/tst_qstatemachine.cpp
@@ -101,6 +101,7 @@ Q_OBJECT
     public:
     SignalEmitter(QObject *parent = 0)
         : QObject(parent) {}
+public Q_SLOTS:
     void emitSignalWithNoArg()
         { emit signalWithNoArg(); }
     void emitSignalWithIntArg(int arg)
@@ -251,6 +252,7 @@ private slots:
     void qtbug_46059();
     void qtbug_46703();
     void postEventFromBeginSelectTransitions();
+    void dontProcessSlotsWhenMachineIsNotRunning();
 };
 
 class TestState : public QState
@@ -6658,5 +6660,35 @@ void tst_QStateMachine::postEventFromBeginSelectTransitions()
     QVERIFY(machine.isRunning());
 }
 
+void tst_QStateMachine::dontProcessSlotsWhenMachineIsNotRunning()
+{
+    QStateMachine machine;
+    QState initialState;
+    QFinalState finalState;
+
+    struct Emitter : SignalEmitter
+    {
+        QThread thread;
+        Emitter(QObject *parent = nullptr) : SignalEmitter(parent)
+        {
+            moveToThread(&thread);
+            thread.start();
+        }
+    } emitter;
+
+    initialState.addTransition(&emitter, &Emitter::signalWithNoArg, &finalState);
+    QTimer::singleShot(0, [&]() {
+        metaObject()->invokeMethod(&emitter, "emitSignalWithNoArg");
+        metaObject()->invokeMethod(&emitter, "emitSignalWithNoArg");
+    });
+    machine.addState(&initialState);
+    machine.addState(&finalState);
+    machine.setInitialState(&initialState);
+    machine.start();
+    connect(&machine, &QStateMachine::finished, &emitter.thread, &QThread::quit);
+    QSignalSpy signalSpy(&machine, &QStateMachine::finished);
+    QTRY_COMPARE_WITH_TIMEOUT(signalSpy.count(), 1, 100);
+}
+
 QTEST_MAIN(tst_QStateMachine)
 #include "tst_qstatemachine.moc"
-- 
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