QBindable: Disallow mutation if read-only

If a QBindable is created from a computed property, it is not possible
to actually set a value or a binding. If we try to do it anyway, we'd
get a crash. Thus we now check whether the function pointer is null
before invoking it.

Pick-to: 6.0
Task-number: QTBUG-87153
Change-Id: I5bedb9080ccf79d9b8166b80d5733d095ed76f8d
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 5 insertions, 0 deletions

diff --git a/tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp b/tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp
index 8145b066da..3cc7bd6f9c 100644
--- a/tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp
+++ b/tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp
@@ -1114,6 +1114,11 @@ void tst_QProperty::testNewStuff()
     object.readData.setValue(111);
     QCOMPARE(object.computed(), 111);
 
+    object.bindableComputed().setBinding(object.bindableBar().makeBinding());
+    QCOMPARE(object.computed(), 111);
+    object.bindableComputed().setValue(10);
+    QCOMPARE(object.computed(), 111);
+
     QCOMPARE(object.bindableFoo().value(), 111);
     object.bindableFoo().setValue(24);
     QCOMPARE(object.foo(), 24);