Allow re-using pre-downloaded wheel source package

What’s the problem this feature will solve?

Using github when building SynoCommunity packages over multiple archs we always try to download all sources once, then lets all builds to run in parallel using the same pre-downloaded source packages.

It is possible to download python wheels using: pip download ... --dest /path/to/destdir --requirement requirements.txt

Although it is not possible (or haven’t found) to call pip wheel so it checks first if the source .tar.gz file isn’t already downloaded when parsing the requirements file such as: pip wheel .... --dest path/to/destdir --requirement requirements.txt

Describe the solution you’d like

Add --dest to list of options to wheel to look for pre-downloaded source files. Pehaps adding a md5sum, sha256sum or similar would be best?

Alternative Solutions

no

Additional context

github-action build output: https://github.com/SynoCommunity/spksrc/pull/4937/checks

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[th0ma7]

@pradyunsg and @uranusjr can I tell it to now install build dependencies when downloading? I mean, I just want it to download them, not initiate an installation.

$ pip download kodipydent-alt==2021.7.16 --no-binary :all: --dest distrib
Collecting kodipydent-alt==2021.7.16
  Downloading kodipydent-alt-2021.7.16.tar.gz (12 kB)
  Installing build dependencies ... /

[th0ma7]

Thnx @uranusjr for the explanations. Then is it re-using the downloaded copy?