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  1. Qt
  2. QTBUG-55725

ProcessEvents hang

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Details

    • Bug
    • Resolution: Cannot Reproduce
    • P2: Important
    • None
    • 5.6.0
    • QPA
    • None
    • Mac OS X
    • macOS

    Description

      I've encountered a hang inside QCocoaEventDispatcher::processEvents.
      What happens (quite difficult to explain to be honest):
      Check the attached screenshot. We are 2 times in QCocoaEventDispatcher::processEvents(). So my previous dialog just closed, endModalSession called, d->interrupt became true, no cleanup session yet. Then I go to 'second' processEvents which is called from QApplication::processEvents, no real dialog here (without exiting the loop in 'first' processEvents) and d->interrupt becomes false again. As a result the loop in 'first' processEvents becomes endless.

      It all looks exactly like QTBUG-45389 which is closed by some reason. I've attached the patch which helps me. Basically I just added cleanupModalSessions into the hanging loop. Could somebody review it and apply if possible?

      Attachments

        1. eventsOverlapHang.zip
          42 kB
          Vitali Prudnikovich
        2. eventsOverlapHang2.zip
          42 kB
          Vitali Prudnikovich
        3. ProcessEvents.png
          854 kB
          Vitali Prudnikovich
        4. qcocoaeventdispatcher.patch
          1 kB
          Vitali Prudnikovich

        Issue Links

          is duplicated by

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-53947 QCocoaEventDispatcher may stay stuck after QEventLoop::exit() is called

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
          replaces

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-45389 Qt hangs when a modal dialog is killed then the parent window calls an event-triggered processEvents() within the (now inactive) modal child's event loop

          • Not Evaluated - Not yet evaluated/prioritized
          • Closed
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          Activity

            People

              dedietri Gabriel de Dietrich (drgvond)
              vitalipf Vitali Prudnikovich
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              Dates

                Created:
                Updated:
                Resolved:

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