Stale lock file causes QtCreator to freeze when starting

[Victor Thompson]

I was debugging why my ubuntu-sdk instance would not start up (it instead freezes indefinitely) when I noticed a stale lock file under ~/.config. I removed this file and the IDE started.

To reproduce:

1. Execute the following from the terminal: touch ~/.config/QtProject/QtCreator.ini.lock
2. Start qtcreator or ubuntu-sdk.

Expected results: The IDE starts as expected
Actual results: The IDE hangs indefinitely

Any sane IDE should be able to handle stale lock files--such a thing should not prevent the application from starting.

[Benjamin Zeller (zeller-benjamin)]

Seems this is related to a regression introduced by this bugfix to Qt: https://bugreports.qt.io/browse/QTBUG-21739

[Timo Jyrinki (timo-jyrinki)]

We need https://codereview.qt-project.org/#/c/104606/ to qtbase or more likely its 5.5 version backported to 5.4 if it's somehow better than that abandoned 5.4 MP.

[Timo Jyrinki (timo-jyrinki)]

Please test from https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/landing-038 (wily only). I don't see a difference in the test case myself though, but I'm not sure if the test case should eg create the file with some certain permissions to mimick old/new Qt behavior. The package now includes the https://codereview.qt-project.org/#/c/109243/

[Benjamin Zeller (zeller-benjamin)]

The Qt version in https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/landing-038 does not fix the freeze for me.