GitHub.com makes commit's date wrong after GPG re-signing

Hello! This topic is a kind of non-security bug report. Please, notify my if there is a better place for such requests.

The issue is based on this SO discussion. In two words, when I perform re-signing and force-pushing via plain old git

git rebase --exec 'git commit --amend --no-edit -n -S' -i --root
git push --force

GitHub overrides the dates of all affected commits. While git itself persists the original dates along with the date when the last gpg-signing was made. For example, git log --show-signature is showing

commit 4078f3c..............3cda
gpg: Signature made Fri Nov 20 18:23:47 2020 MSK
gpg:                using RSA key 6E0E.............79EF
gpg:                issuer "my@email"
gpg: Good signature from "Denis Hilt <my@email>" [ultimate]
Author: dhilt <my@email>
Date:   Thu Aug 18 16:16:01 2016 +0300

    initial sources commit

And we see Aug 18, 2016 as the date of commit and Nov 20, 2020 as the date of gpg-signing. And the same entry on the GitHub (after force-push) as follows:

It ignores the real commit date and shows the date of last gpg-sign instead. I believe it should not be so. The date of last gpg-sign could be shown in the GPG popup:

Screenshot 2020-11-20 at 19.22.38

It is quite important for the GitHub to reflect the same original commit date as the git provides via git log.

Is this the right place for my question? Where should I raise it if not?

Thanks!

I have observed before that Github uses the commit date, not the author date, for the time shown in the web GUI. By default amending changes only the former. I assume that causes the difference you’re seeing. In other words, I’m pretty sure that has nothing to do with the signature as such, and everything with amending the commit. You can check the commit and author date with:

git log --pretty=fuller
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