ahmadsamir added a comment.
In D28478#645682 <https://phabricator.kde.org/D28478#645682>, @dfaure wrote: > In D28478#645019 <https://phabricator.kde.org/D28478#645019>, @ahmadsamir wrote: > > > hmm... first this is a copy-paste "error" on my part, I personally never use & when the RHS is a temporary (I don't see the point). > > > The point is to avoid a copy ;-) > > If the RHS is a value, this extends its lifetime. > But if it's a reference itself, then indeed we depend on its lifetime.... > > > the job may finish and get deleted by the time we call entry.numberValue() on line 1534. > > That's not a "guess", it's confirmed by what ASAN tells us in its second backtrace. > > > And maybe statResult() shouldn't return a reference (or a const reference for that matter, because if the caller uses 'entry = job->statResult()' > > then statResult() returning a const & doesn't make any difference if it's copied...). > > Well you get two copies then, one at "return" and one at '=' (technically that's an assignment, unless entry is actually declared on the same line). I meant something like: const int i = foo(); the return from foo() is copied into i and then it's gone. const int &i = foo(); the return from foo() will be stored in a temporary, and it will stay around until i goes out of scope. So, there's only one "copy" of the return from foo() around, I'd rather take the one stored in i (https://herbsutter.com/2013/05/13/gotw-2-solution-temporary-objects/); I know that's nitpicking, but anyway. So mainly when it's an initialisation rather than assignment. :) > Anyhow the fix is clear, remove the & :-) OK, will do. REPOSITORY R241 KIO REVISION DETAIL https://phabricator.kde.org/D28478 To: ahmadsamir, #frameworks, dfaure, meven, bruns Cc: kde-frameworks-devel, LeGast00n, cblack, GB_2, michaelh, ngraham, bruns
