Connect quit() and exit() signals with queued connections

Class QQmlApplicationEngine connects QQmlApplicationEngine::quit()
signal to QCoreApplication::quit() and QQmlApplicationEngine::exit()
signal to QCoreApplication::exit(), but it does so with AutoConnection.
This causes in some circumstances problems, which are described in Qt
documentation (see QCoreApplication::exit()). This change modifies type
of connections to queued connections.

[ChangeLog][QtQml][QQmlApplicationEngine] QQmlApplicationEngine
connects quit() and exit() signals with queued connections to avoid
problems with AutoConnection, when connecting to QCoreApplication
slots.

Task-number: QTBUG-73649
Change-Id: Ib27738b5af2f879efee8862b1ca01613a2e8dc4e
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

7 files changed, 65 insertions, 13 deletions

diff --git a/tests/auto/qml/qqmlapplicationengine/testapp/delayedExit.qml b/tests/auto/qml/qqmlapplicationengine/testapp/delayedExit.qml
new file mode 100644
index 0000000000..3d67c958bb
--- /dev/null
+++ b/tests/auto/qml/qqmlapplicationengine/testapp/delayedExit.qml
@@ -0,0 +1,11 @@
+import QtQml 2.0
+
+QtObject {
+    id: root
+    property Timer t: Timer { interval: 1; running: true; onTriggered: Qt.exit(0); }
+    property Connections c: Connections {
+        target: Qt.application
+        onAboutToQuit: console.log("End");
+    }
+    Component.onCompleted: console.log("Start: " + Qt.application.arguments[1]);
+}
diff --git a/tests/auto/qml/qqmlapplicationengine/testapp/main.qml b/tests/auto/qml/qqmlapplicationengine/testapp/delayedQuit.qml
index c75485a7f7..c75485a7f7 100644
--- a/tests/auto/qml/qqmlapplicationengine/testapp/main.qml
+++ b/tests/auto/qml/qqmlapplicationengine/testapp/delayedQuit.qml
diff --git a/tests/auto/qml/qqmlapplicationengine/testapp/immediateExit.qml b/tests/auto/qml/qqmlapplicationengine/testapp/immediateExit.qml
new file mode 100644
index 0000000000..46634f3f51
--- /dev/null
+++ b/tests/auto/qml/qqmlapplicationengine/testapp/immediateExit.qml
@@ -0,0 +1,8 @@
+import QtQml 2.0
+
+QtObject {
+    Component.onCompleted: {
+        console.log("End: " + Qt.application.arguments[1]);
+        Qt.exit(0)
+    }
+}
diff --git a/tests/auto/qml/qqmlapplicationengine/testapp/immediateQuit.qml b/tests/auto/qml/qqmlapplicationengine/testapp/immediateQuit.qml
new file mode 100644
index 0000000000..1da9d1201a
--- /dev/null
+++ b/tests/auto/qml/qqmlapplicationengine/testapp/immediateQuit.qml
@@ -0,0 +1,8 @@
+import QtQml 2.0
+
+QtObject {
+    Component.onCompleted: {
+        console.log("End: " + Qt.application.arguments[1]);
+        Qt.quit()
+    }
+}
diff --git a/tests/auto/qml/qqmlapplicationengine/testapp/main.cpp b/tests/auto/qml/qqmlapplicationengine/testapp/main.cpp
index a57889fe86..be0d98a2df 100644
--- a/tests/auto/qml/qqmlapplicationengine/testapp/main.cpp
+++ b/tests/auto/qml/qqmlapplicationengine/testapp/main.cpp
@@ -32,6 +32,6 @@
 int main (int argc, char *argv[])
 {
     QCoreApplication app(argc, argv);
-    QQmlApplicationEngine e(QUrl("qrc:///main.qml"));
+    QQmlApplicationEngine e(QUrl(QString("qrc:///") + argv[1]));
     return app.exec();
 }
diff --git a/tests/auto/qml/qqmlapplicationengine/testapp/main.qrc b/tests/auto/qml/qqmlapplicationengine/testapp/main.qrc
index 5f6483ac33..82b695bbd8 100644
--- a/tests/auto/qml/qqmlapplicationengine/testapp/main.qrc
+++ b/tests/auto/qml/qqmlapplicationengine/testapp/main.qrc
@@ -1,5 +1,8 @@
 <RCC>
     <qresource prefix="/">
-        <file>main.qml</file>
+        <file>immediateQuit.qml</file>
+        <file>immediateExit.qml</file>
+        <file>delayedQuit.qml</file>
+        <file>delayedExit.qml</file>
     </qresource>
 </RCC>
diff --git a/tests/auto/qml/qqmlapplicationengine/tst_qqmlapplicationengine.cpp b/tests/auto/qml/qqmlapplicationengine/tst_qqmlapplicationengine.cpp
index daeb9b5455..ce654dc45e 100644
--- a/tests/auto/qml/qqmlapplicationengine/tst_qqmlapplicationengine.cpp
+++ b/tests/auto/qml/qqmlapplicationengine/tst_qqmlapplicationengine.cpp
@@ -46,6 +46,7 @@ private slots:
     void initTestCase();
     void basicLoading();
     void testNonResolvedPath();
+    void application_data();
     void application();
     void applicationProperties();
     void removeObjectsWhenDestroyed();
@@ -111,35 +112,56 @@ void tst_qqmlapplicationengine::testNonResolvedPath()
     }
 }
 
+void tst_qqmlapplicationengine::application_data()
+{
+    QTest::addColumn<QByteArray>("qmlFile");
+    QTest::addColumn<QByteArray>("expectedStdErr");
+
+    QTest::newRow("delayed quit") << QByteArray("delayedQuit.qml")
+                                  << QByteArray("qml: Start: delayedQuit.qml\nqml: End\n");
+    QTest::newRow("delayed exit") << QByteArray("delayedExit.qml")
+                                  << QByteArray("qml: Start: delayedExit.qml\nqml: End\n");
+    QTest::newRow("immediate quit") << QByteArray("immediateQuit.qml")
+                                    << QByteArray("qml: End: immediateQuit.qml\n");
+    QTest::newRow("immediate exit") << QByteArray("immediateExit.qml")
+                                    << QByteArray("qml: End: immediateExit.qml\n");
+}
+
 void tst_qqmlapplicationengine::application()
 {
     /* This test batches together some tests about running an external application
        written with QQmlApplicationEngine. The application tests the following functionality
        which is easier to do by watching a separate process:
-       -Loads relative paths from the working directory
-       -quits when quit is called
-       -emits aboutToQuit after quit is called
-       -has access to application command line arguments
+       - Loads relative paths from the working directory
+       - Quits when quit is called
+       - Exits when exit is called
+       - Emits aboutToQuit after quit is called
+       - Has access to application command line arguments
 
        Note that checking the output means that on builds with extra debugging, this might fail with a false positive.
        Also the testapp is automatically built and installed in shadow builds, so it does NOT use testData
    */
+
+    QFETCH(QByteArray, qmlFile);
+    QFETCH(QByteArray, expectedStdErr);
+
 #if QT_CONFIG(process)
     QDir::setCurrent(buildDir);
     QProcess *testProcess = new QProcess(this);
     QStringList args;
-    args << QLatin1String("testData");
+    args << qmlFile; // QML file passed as an argument is going to be run by testapp.
     testProcess->start(QLatin1String("testapp/testapp"), args);
     QVERIFY(testProcess->waitForFinished(5000));
     QCOMPARE(testProcess->exitCode(), 0);
-    QByteArray test_stdout = testProcess->readAllStandardOutput();
-    QByteArray test_stderr = testProcess->readAllStandardError();
-    QByteArray test_stderr_target("qml: Start: testData\nqml: End\n");
+    QByteArray testStdOut = testProcess->readAllStandardOutput();
+    QByteArray testStdErr = testProcess->readAllStandardError();
 #ifdef Q_OS_WIN
-    test_stderr_target.replace('\n', QByteArray("\r\n"));
+    expectedStdErr.replace('\n', QByteArray("\r\n"));
 #endif
-    QCOMPARE(test_stdout, QByteArray(""));
-    QVERIFY(QString(test_stderr).endsWith(QString(test_stderr_target)));
+    QCOMPARE(testStdOut, QByteArray(""));
+    QVERIFY2(QString(testStdErr).endsWith(QString(expectedStdErr)),
+             QByteArray("\nExpected ending:\n") + expectedStdErr
+             + QByteArray("\nActual output:\n") + testStdErr);
     delete testProcess;
     QDir::setCurrent(srcDir);
 #else // process