Crash in QString OwncloudPropagator::fullLocalPath

[sentry-io]

Sentry Issue: DESKTOP-WIN-AND-MAC-AYF

EXCEPTION_ACCESS_VIOLATION_READ: Fatal Error: EXCEPTION_ACCESS_VIOLATION_READ
  File "qbytearray.h", line 506, in QString::QString
  File "owncloudpropagator.cpp", line 598, in OCC::OwncloudPropagator::fullLocalPath
  File "owncloudpropagator.cpp", line 762, in OCC::OwncloudPropagator::updateMetadata
  File "propagateremotemkdir.cpp", line 180, in <lambda>::operator()
  File "qtconcurrentstoredfunctioncall.h", line 60, in QtConcurrent::StoredFunctorCall0<T>::runFunctor
...
(5 additional frame(s) were not displayed)

[erikjv]

The future where this is executed gets the parent propagator pointer passed into it. I think that that parent object has been freed by the time the future needs it.

[erikjv]

Actually, the future holds on to the PropagateRemoteMkdir through an std::shared_ptr. But this is a QObject subclass, with a parent (which is returned by the propagator() call), so this object will probably be deleted when the parent disappears. Passed into the future is a lambda, which get the parent (pointer) by value.

So could the following be the fix (propagateremotemkdir.cpp:157):

- auto *watcher = new QFutureWatcher<resultTypePtr>(this);
+ auto *watcher = new QFutureWatcher<resultTypePtr>(propagator());

So hold on to the parent, thereby preventing deletion of the child, plus keeping that parent alive for inside the lambda?