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  1. Qt
  2. QTBUG-74532

qmlcachegen produces indeterministic output

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    • Linux/X11
    • 497a795081b95d487f0ec33746cc2a12ffeae5a0 (qt/qtdeclarative/5.12)

    Description

      While working on reproducible builds for openSUSE, I found that
      when building the libqt5-qtquickcontrols package for openSUSE Linux, there were slight differences between each build: 1-byte diffs in various qmlc files.
       
      Further analysis showed that this can be reproduced with

      /usr/lib64/qt5/bin/qmlcachegen -o x EditMenu_base.qml
      md5sum x
       
      and variations go away when disabling ASLR with setarch `arch` -R

      See  https://github.com/bmwiedemann/theunreproduciblepackage/tree/master/aslr for examples of how ASLR introduces non-determinism.

       

      I attached a 10-line minimal reproducer example.qml file.

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            ulherman Ulf Hermann
            bmwiedemann Bernhard M. Wiedemann
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              Updated:
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