QQmlNotifier: Always keep the isNotifying flag when updating senderPtr

When the sender gets deleted we still want to retain the flag that tells
us that the notifier is currently active. Otherwise we can miss the
error message about synchronously deleting objects while signal handlers
are in progress.

Task-number: QTBUG-73013
Change-Id: I8abba9b492327c15963d1875841c6822f345a89e
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 41 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlnotifier/data/objectRenamer.qml b/tests/auto/qml/qqmlnotifier/data/objectRenamer.qml
new file mode 100644
index 0000000000..65d2206880
--- /dev/null
+++ b/tests/auto/qml/qqmlnotifier/data/objectRenamer.qml
@@ -0,0 +1,9 @@
+import QtQml 2.2
+
+QtObject {
+    property Timer timer: Timer {
+        running: true
+        interval: 0
+        onTriggered: parent.objectName = "havoc"
+    }
+}
diff --git a/tests/auto/qml/qqmlnotifier/tst_qqmlnotifier.cpp b/tests/auto/qml/qqmlnotifier/tst_qqmlnotifier.cpp
index 8811f779bb..6e831eacc1 100644
--- a/tests/auto/qml/qqmlnotifier/tst_qqmlnotifier.cpp
+++ b/tests/auto/qml/qqmlnotifier/tst_qqmlnotifier.cpp
@@ -32,6 +32,9 @@
 #include <QQmlContext>
 #include <qqml.h>
 #include <QMetaMethod>
+#if QT_CONFIG(process)
+#include <QProcess>
+#endif
 
 #include "../../shared/util.h"
 
@@ -156,6 +159,8 @@ private slots:
     void disconnectOnDestroy();
     void lotsOfBindings();
 
+    void deleteFromHandler();
+
 private:
     void createObjects();
 
@@ -335,6 +340,33 @@ void tst_qqmlnotifier::lotsOfBindings()
     delete e;
 }
 
+void tst_qqmlnotifier::deleteFromHandler()
+{
+#if !QT_CONFIG(process)
+    QSKIP("Need QProcess support to test qFatal.");
+#else
+    if (qEnvironmentVariableIsSet("TST_QQMLNOTIFIER_DO_CRASH")) {
+        QQmlEngine engine;
+        QQmlComponent component(&engine, testFileUrl("objectRenamer.qml"));
+        QPointer<QObject> mess = component.create();
+        QObject::connect(mess, &QObject::objectNameChanged, [&]() { delete mess; });
+        QTRY_VERIFY(mess.isNull()); // BANG!
+    } else {
+        QProcess process;
+        QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
+        env.insert("TST_QQMLNOTIFIER_DO_CRASH", "bang");
+        process.setProcessEnvironment(env);
+        process.setProgram(QCoreApplication::applicationFilePath());
+        process.setArguments({"deleteFromHandler"});
+        process.start();
+        QTRY_COMPARE(process.exitStatus(), QProcess::CrashExit);
+        const QByteArray output = process.readAllStandardOutput();
+        QVERIFY(output.contains("QFATAL"));
+        QVERIFY(output.contains("destroyed while one of its QML signal handlers is in progress"));
+    }
+#endif
+}
+
 QTEST_MAIN(tst_qqmlnotifier)
 
 #include "tst_qqmlnotifier.moc"