Before this change the done() signal was emitted 3 times
in a row. The reason was that first one was coming
synchonously from handleGotoDefinitionResult(), while
2 others were scheluded with queued connections.
So, the handler for done() signal was called 3 times.
The first invocation calls deleteLater() and clears
the pointer, while the object is still alive.
Before the request to delete later gets dispatched,
the 2 remaining done() emissions are dispatched,
so the handler is still called 2 times.
One possible solution would be to disconnect from
done() signal inside a handler. However, the done()
signal shouldn't be called many times, so this fix
ensures the done() is emitted only once.
This fixes the following prinouts:
"QCoreApplication::postEvent: Unexpected null receiver"
issued twice on every follow symbol interaction.
Amends 650bc260c6
Change-Id: I9b440a80386aca3462eda323e51a76696e53fa6b
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
