qgis3: Build does not honor selected python version

[aaschwanden (Andy Aschwanden)]

Updating/installing qgis3 with python 3.8 with

sudo port -vN install qgis3 -python39 +python38 +clang90 +mpich

results in

-- Found GSL: -L/opt/local/lib -lgsl -lgslcblas
-- Found Python executable: /opt/local/bin/python3.9 (version 3.9.6)
-- Python library: /opt/local/Library/Frameworks/Python.framework/Versions/3.9/lib/libpython3.9.dylib
-- Python site-packages: /opt/local/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages
Traceback (most recent call last):
  File "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_gis_qgis3/qgis3/work/QGIS-3_20_0/cmake/FindPyQt5.py", line 34, in <module>
    import PyQt5.QtCore
ModuleNotFoundError: No module named 'PyQt5'
CMake Error at cmake/FindPyQt5.cmake:55 (MESSAGE):
  Could not find PyQt5

I'm not sure why it trys to use python39 instead of the selected python38.

[Veence (Vincent)]

Ok, I’m going to have a look to this. I apologise for being all but absent lately. I had a hectic spring, with really little time to dedicate to anything except work. I’ll come back with a patch before the end of the week

[Veence (Vincent)]

I’m not sure why it says that. Python39 seems to be a non-overridable choice. What is the result of

port select python

?

[piyushrpt]

This is likely caused by this line using PYTHON_EXECUTABLE instead of Python_EXECUTABLE, related to deprecation of FindPythonInterp in favor of FindPython in cmake.

​https://github.com/macports/macports-ports/blob/master/gis/qgis3/Portfile#L202

[Veence (Vincent)]

Aha. Well spotted. I’m going to change that right away. Thanks for reporting!

[Veence (Vincent)]

Ok, I've committed a new version. I didn't rev-bump the portfile, though. Please wait for a few hours, and try again. I can’t really do that myself, because using +python38 conflicts with my default +python39. Please report success or failure. Thanks!

[piyushrpt]

Worked for me.

[Veence (Vincent)]

Wonderful! I close this ticket, then.