This will be a very, very tricky thing to implement, with a very real possibility of frequent failures.

We recently saw a couple contributors reply directly in the PR to mails that had been mirrored from the Git mailing list (as PR comments). This does not currently work because the good people on the Git mailing list do not pay attention to GitGitGadget PRs.

To help that, try to figure out which mail to reply to, and send the comment (editing the comment to include a note that it was sent with a link to the mailing list archive).

To figure out what mail to reply to, in the first run, we should look for a quoted link to the mailing list archive (which includes the Message-ID): every PR comment that was mirrored from a corresponding mail on the Git mailing list starts with a link "On the Git mailing list" with a URL to the archive at https://public-inbox.org/git/.

If there is no such quoted link, we could see whether the comment to send contains some quoted text, and if it does not, bail out by adding another comment stating that GitGitGadget could not figure out what mail this reply was for, and please do include the quoted link at the beginning if you want it to be mirrored.