StateMachine: Don't crash if no signal is passed to SignalTransition

Rather, just reset the transition.

Fixes: QTBUG-110286
Change-Id: Ic25a6c7b841a47b180e1a62c7bdbd2e388cdc293
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Juha Vuolle <juha.vuolle@qt.io>
(cherry picked from commit af4c8da54bbf057f3a8d7cf8a8e4146d35aad7f6)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 9 insertions, 1 deletions

diff --git a/src/statemachineqml/signaltransition.cpp b/src/statemachineqml/signaltransition.cpp
index 9963d31..95b20f0 100644
--- a/src/statemachineqml/signaltransition.cpp
+++ b/src/statemachineqml/signaltransition.cpp
@@ -203,7 +203,11 @@ void SignalTransition::connectTriggered()
     QV4::Scope scope(jsEngine);
     QV4::Scoped<QV4::QObjectMethod> qobjectSignal(
                 scope, QJSValuePrivate::asReturnedValue(&m_signal.value()));
-    Q_ASSERT(qobjectSignal);
+    if (!qobjectSignal) {
+        m_signalExpression.adopt(nullptr);
+        return;
+    }
+
     QMetaMethod metaMethod = target->metaObject()->method(qobjectSignal->methodIndex());
     int signalIndex = QMetaObjectPrivate::signalIndex(metaMethod);
 
diff --git a/tests/auto/qml/qqmlstatemachine/data/signaltransition.qml b/tests/auto/qml/qqmlstatemachine/data/signaltransition.qml
index 52c62a7..09f344a 100644
--- a/tests/auto/qml/qqmlstatemachine/data/signaltransition.qml
+++ b/tests/auto/qml/qqmlstatemachine/data/signaltransition.qml
@@ -48,4 +48,8 @@ Item {
         guard: 2 + 2
     }
 
+    SignalTransition {
+        // Do not crash on SignalTransition without signal
+        onTriggered: () => {}
+    }
 }