Why the GitHub Action installs project dependencies via pip download + pip install --find-links

[fynxiu]

Documentation

In action.yml, the GitHub Action installs project dependencies with:

"$VENV_PYTHON" -m pip download --dest="$VENV"/deps .
"$VENV_PYTHON" -m pip install -U --find-links="$VENV"/deps "$VENV"/deps/*

instead of a more direct approach such as:

"$VENV_PYTHON" -m pip install .

I looked through the current file and the original commit that introduced the action (e028045), but I could not find an explanation for why this two-step install flow was
chosen.

Could you document the intended reason for this design?

Questions I am trying to answer:

1. Is there a functional advantage over pip install . for this action?
2. Is the goal to stage artifacts locally before installation, improve debuggability, or work around some pip / GitHub Actions behavior?
3. If there is no longer a strong reason, would simplifying this step be acceptable?

A short comment in action.yml or a note in the action documentation would help future readers understand the tradeoff.

[dhanusharer]

Hi! I would like to work on this issue.

I will investigate the current two-step installation flow in action.yml and add a short comment explaining the reasoning behind using pip download followed by pip install --find-links instead of a direct pip install ..

Please let me know if there are any specific details you would like the documentation comment to include.

[dhanusharer]

Hi! I’ve opened a PR to add documentation explaining the two-step dependency installation process used in action.yml.

PR: #20996

[A5rocks]

It seems to me that there's no difference. Maybe I'm missing something... @elprans do you still remember?