D18245: [DrKonqi] Create QApplication in a scope to fix possible deadlock

[Christoph Roick]

croick created this revision.
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REVISION SUMMARY
  Observed with a crashing KDevelop:
  If the QApplication is destructed after cleanup of the DrKonqi
  backend, somehow a DrKonqi-thread of the QDBusConnection may be
  blocked by the debuggee (poll() being stuck according to strace).
  Since DrKonqi then cannot quit, KCrash continues waiting, leading
  to a deadlock. The situation may be disentangled by externally
  sending SIGSTOP to the debuggee.
  
  Cleaning up the QApplication first and afterwards the backend
  omits the deadlock.

TEST PLAN
  - let kdevelop crash to fire up DrKonqi
  - close DrKonqi again
  - watch state of crashed kdevelop process

REPOSITORY
  R871 DrKonqi

BRANCH
  scopedqapp

REVISION DETAIL
  https://phabricator.kde.org/D18245

AFFECTED FILES
  src/main.cpp

To: croick
Cc: plasma-devel, sukalyanbanga, jraleigh, GB_2, ragreen, Pitel, ZrenBot, lesliezhai, ali-mohamed, jensreuterberg, abetts, sebas, apol, mart
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