Re: [PATCH v2] push: fix --force-if-includes when remote-tracking ref has no reflog

Junio C Hamano <gitster@pobox.com> writes:

Entries older than 90 days do survive. The reflog expires when gc or "git reflog expire" runs, not on its own, so I could build a branch whose matching reflog entry is 200 days old and still sitting there.

A/B on one scenario with only the fallback differing: with now minus 90 days the push is rejected, with zero it goes through as a forced update. The branch was created at the remote tip 200 days ago, that entry being the matching one, rewound below the tip 150 days ago, one recent commit on top, so the tip is not an ancestor of anything newer.

It takes two crossings of the bound to bite, which is why my first two attempts to reproduce it failed. The match is tested before the cut-off, so the entry sitting at the bound is still inspected, and the merge-base fallback still covers the case where the tip is reachable from something collected. You need a non-matching entry past the bound and the tip unreachable from what was collected.

v3 went out a few hours before your mail; its third paragraph argues zero over "now" or a fixed age. Your call.