Store *.pyc files outside the app bundle

[morinted]

If we ever want to code sign the app bundle on Mac, we can't have *.pyc files generate in the embedded Python.framework.

Code signing takes into account all the contents of the app bundle. Currently on first run, python compiles all the byte-code and places it alongside the framework in the app bundle, which would invalidate the signature.

We should investigate whether PYTHONCACHEPREFIX (python3.8+) could be used to store the pyc files in ~/Library/Application Support/Open Steno Project/Plover` instead.

[benoit-pierre]

Don't we already remove (most) Python source files? (via plover_build_utils.source_less)

Is the issue with the Python modules we keep as source?

[benoit-pierre]

(And make sure we compile those, even if we keep them).

[morinted]

Hmm, you're right. For fun, I took a copy of Plover freshly downloaded, backed it up, and ran the original and closed Plover.

Looks like the folders are the same size on disk and diff -r Plover.app Plover2.app returned nothing. So this may be a nonissue!

[benoit-pierre]

We don't compile those source files we keep:

> fd '_in_process.*' plover-4.0.0.dev8+369.gd324d4e-macosx_10_13_x86_64
plover-4.0.0.dev8+369.gd324d4e-macosx_10_13_x86_64/Plover/Plover.app/Contents/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pip/_vendor/pep517/_in_process.py

If we don't fix that, I except some other fun issues when installing plugins.

[benoit-pierre]

We could also just keep the sources, and make sure we pre-compile everything to bytecode. I don't remember how much was saved by making distributions source-less. But now that we don't include Qt's WebEngine, we have some room to spare.