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  1. Qt
  2. QTBUG-139122

Can't set exception after QPromise was canceled

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    • Icon: Bug Bug
    • Resolution: Unresolved
    • Icon: P3: Somewhat important P3: Somewhat important
    • None
    • 6.9.1
    • Core: Threads
    • None
    • All

      IMHO QFuture::waitForFinished should throw QPromise exception even if it was canceled.

      See the attached example for better understanding.

      Mind the Q_ASSERTs in the source code, all should pass.

       

      We should be able to set exceptions on all states but finished.

      It's very useful to catch a custom canceled exception in a try/catch

      block.

      e.g.

       

      class CanceledException : public QException
{...}
...
if (promise.isCanceled()
    promise.setException(CanceledException{});
else
    promise.addResult(result);
...
 
try {
    auto res = future.takeResult();
} catch (const CanceledException &) {
    // handle canceled
} catch (const AnotherSpeciticException &) {
    // AnotherSpecitic
}

       

       

        1. main.cpp
          1 kB
          BogDan Vatra
        For Gerrit Dashboard: QTBUG-139122
        # Subject Branch Project Status CR V
        668842,3 WIP: Set exception if we're in cancel state dev qt/qtbase Status: NEW -2 0

            cnn Qt Core & Network
            taipan BogDan Vatra
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              Created:
              Updated:

                There is 1 open Gerrit change