During the build, the buildpack makes the config vars set on the app available to certain subprocesses (such as Django collectstatic) via the sub_env utility function. This function filters out env vars that might cause the subprocess to fail.
This change adds LD_LIBRARY_PATH and PYTHONHOME to the list of env vars that are filtered out, to prevent errors when they are set to invalid values. (Note: This filtering only affects app config vars, and not the env vars provided by buildpacks that run prior to the Python buildpack.)
These broken app config vars have not typically caused problems since:
Only Python apps created in 2012 or earlier will have them (unless someone manually sets them on an app)
Static builds of Python don't rely upon LD_LIBRARY_PATH
However, as of Python 3.10 we switched to building in shared mode (see #1320), and so apps with broken config vars will otherwise see errors like the following once they upgrade Python versions:
python: error while loading shared libraries: libpython3.10.so.1.0: cannot open shared object file: No such file or directory
The GIT_DIR env var was removed from the filter list, since there is no need to filter it out, since it's no longer set by the build system, see #1120.
(The CNB isn't affected by this issue, and already has a test to confirm that.)
During the build, the buildpack makes the config vars set on the app available to certain subprocesses (such as Django collectstatic) via the
sub_envutility function. This function filters out env vars that might cause the subprocess to fail.This change adds
LD_LIBRARY_PATHandPYTHONHOMEto the list of env vars that are filtered out, to prevent errors when they are set to invalid values. (Note: This filtering only affects app config vars, and not the env vars provided by buildpacks that run prior to the Python buildpack.)In particular, very old versions of the buildpack used to set these env vars as actual app config vars (via the
bin/releasescript), to values that no longer work: https://github.com/heroku/heroku-buildpack-python/blob/27abdfe7d7ad104dabceb45641415251e965671c/bin/release#L11-L18These broken app config vars have not typically caused problems since:
LD_LIBRARY_PATHHowever, as of Python 3.10 we switched to building in shared mode (see #1320), and so apps with broken config vars will otherwise see errors like the following once they upgrade Python versions:
As seen in: https://heroku.support/1309696 https://heroku.support/1365030
The
GIT_DIRenv var was removed from the filter list, since there is no need to filter it out, since it's no longer set by the build system, see #1120.(The CNB isn't affected by this issue, and already has a test to confirm that.)
GUS-W-15519103.