[AppImage] Missing libgthread-2.0.so.0

[teohhanhui]

Steps to reproduce

On openSUSE MicroOS, trying to run the AppImage fails:

teohhanhui@envy-x360:~/Downloads> ./Syncplay-1.6.8-x86_64.AppImage
Could not import GUI libraries. If you do not have PySide installed then you will need to install it for the GUI to work.
Hostname can't be empty!
Some necessary arguments are missing, refer to --help

Diagnosis

Unfortunately setting the QT_DEBUG_PLUGINS=1 environment variable doesn't produce any additional output. It seems like the failure happens too early in the process.

But QT_VERBOSE=1 does work (since it's used by the Python code and not Qt itself):

teohhanhui@envy-x360:~/Downloads> export QT_VERBOSE=1
teohhanhui@envy-x360:~/Downloads> ./Syncplay-1.6.8-x86_64.AppImage 
Order: 'PySide2', 'PySide', 'PyQt5', 'PyQt4'
Trying PySide2
Misplaced member has no source: QtGui.QStringListModel
Misplaced member has no source: QtCore.Property
Misplaced member has no source: QtCore.Signal
Misplaced member has no source: QtCore.Slot
Misplaced member has no source: QtCore.QAbstractProxyModel
Misplaced member has no source: QtCore.QSortFilterProxyModel
Misplaced member has no source: QtCore.QItemSelection
Misplaced member has no source: QtCore.QItemSelectionModel
Misplaced member has no source: QtCore.QItemSelectionRange
QtCompat: AttributeError: partially initialized module 'syncplay.vendor.Qt' has no attribute '_QtWidgets' (most likely due to a circular import)
QtCompat: AttributeError: partially initialized module 'syncplay.vendor.Qt' has no attribute '_QtWidgets' (most likely due to a circular import)
QtCompat: AttributeError: partially initialized module 'syncplay.vendor.Qt' has no attribute '_QtWidgets' (most likely due to a circular import)
QtCompat: AttributeError: partially initialized module 'syncplay.vendor.Qt' has no attribute '_QtWidgets' (most likely due to a circular import)
QtCompat: AttributeError: partially initialized module 'syncplay.vendor.Qt' has no attribute '_QtWidgets' (most likely due to a circular import)
QtCompat: AttributeError: partially initialized module 'syncplay.vendor.Qt' has no attribute '_QtWidgets' (most likely due to a circular import)
QtCompat: AttributeError: partially initialized module 'syncplay.vendor.Qt' has no attribute '_QtWidgets' (most likely due to a circular import)
QtCompat: AttributeError: partially initialized module 'syncplay.vendor.Qt' has no attribute '_QtWidgets' (most likely due to a circular import)
QtCompat: AttributeError: partially initialized module 'syncplay.vendor.Qt' has no attribute '_QtWidgets' (most likely due to a circular import)
Could not import GUI libraries. If you do not have PySide installed then you will need to install it for the GUI to work.
Hostname can't be empty!
Some necessary arguments are missing, refer to --help

We can see the actual error on import:

teohhanhui@envy-x360:~> python3
Python 3.8.10 (default, May 05 2021, 15:36:36) [GCC] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from PySide2 import QtCore
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: libgthread-2.0.so.0: cannot open shared object file: No such file or directory

Workaround

Manually install libgthread-2_0-0 package.

Possible solution

I can see that copy_deps in pkg2appimage is supposed to find all the shared libraries to be copied. But if there are missing libraries (e.g. libgthread-2.0.so.0 => not found) that wouldn't work: https://github.com/AppImage/pkg2appimage/blob/23e510b394fc28d24386e2eba076132a646f456c/functions.sh#L95-L109

I think we can install the missing libglib2.0-0 package in the GitHub Actions build:

syncplay/.github/workflows/build.yml

Line 134 in 77ce05d

sudo apt-get install libxkbcommon-x11-0

This seems to be the same problem that made it necessary to hardcode libxkbcommon-x11.so.0 here:

syncplay/ci/appimage-script.sh

Line 112 in 9d1deeb

--output appimage --custom-apprun AppRun.sh -l /usr/lib/x86_64-linux-gnu/libxkbcommon-x11.so.0

If my theory is correct then this hardcoding should not be necessary.