Not clearing the continuationData could lead to use-after-free when
there is an attempt to cancel an already finished future, which belongs
to an already-destroyed promise.
This patch fixes it be explicitly resetting continuationData to nullptr
in the clearContinuation() method, which is called from the QPromise
destructor.
Task-number: QTBUG-103514
Pick-to: 6.5 6.4 6.2
Change-Id: I6418b3f5ad04f2fdc13a196ae208009eaa5de367
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
b34bea5e96