remove unstable git archival config

[zeke]

This PR is an attempt to change our git configuration to prevent unintended changes in checksums as we create new releases.

From @Bo98 in Homebrew/homebrew-core#162013 (comment)

The %D format used in

cog/python/.git_archival.txt

Line 4 in a81c7a4

ref-names: $Format:%D$

is not a stable format and can change depending on HEAD.

ref-names looks like it is actually only necessary to have if using a Git older than 2.32 - describe-name is used instead on modern Git. I'm not sure if that's a concern for cog or not, but removing ref-names could be the fix here. An alternative would be to upload your own stable source archive on releases.

For the record, I Have No Idea What I'm Doing here. 🐶 Not sure if this is the right approach, and just trying to unblock our Homebrew releases. Relying on smarter people to weigh in on whether this is the right change. 🙏🏼

Resolves #1518

[stefanb]

Is it expected that this change will only affect the hashes of the future cog release archives or also the existing ones (eg current last release 0.9.4)?

cc @nickstenning , the author of the changed lines in d2726e0

[nickstenning]

I'm not sure I understand what has happened here. I get that the export-subst configuration produces output that depends on what HEAD points to, but what I don't understand is how the source tarball actually changed?

Did it change because GitHub changed how the tarballs are generated, i.e. they previously were on main when they generate the export, but now they check out the tag itself?

Edit: looks like it's the opposite. Previously the tarball was generated with HEAD -> main and with working copy from the tag, and now they're on main with working copy from main.

[nickstenning]

Is it expected that this change will only affect the hashes of the future cog release archives or also the existing ones (eg current last release 0.9.4)?

As far as I can tell it's the export-subst configuration at the relevant treeish that is used during archive, and not the one checked out, so changing this should only change the hashes of future source tarballs.

[nickstenning]

I pushed a commit to this branch to move .git_archival.txt to the root of the repository. It turns out that the relevant setuptools_scm code (to generate the right version for the Python package when installed from an archive tarball) has been broken since d86fb17.

[nickstenning]

LGTM

[nickstenning]

I'm going to go ahead and get this merged. Thank you for picking it up @zeke :)