Short description and remediation
we force-pushed master branch back to an earlier commit in history to revert a merge that added a significant amount of size to the history. If you happened to update your local master branch durring the window where the now removed commit were on master (or just out of an abundance of caution) please do
git remote update
git checkout master
# be sure you don't have any commits on your master before you do this!
git reset --hard origin/master
to get your local branch sorted out.
Medium description
When me merged https://github.com/matplotlib/matplotlib/pull/8896 we accidentally put several full sets of test images in, it has been less than 24 hours and only 2 PRs have been merged and one opened (all of which are from @anntzer.lee). There was some discussion on gitter (https://gitter.im/matplotlib/matplotlib?at=5e3e96051d23aa47aa003c3b). I made the snap decision to roll back master because:
- No commit was re-written, only the master branch was moved back to a commit that was already in the tree. The worst-case fix for this is to merge the previous head back in and we will still have a fully consistent history.
- I expect the impact to be low, we are only going back ~20 hours over a Friday night / Saturday morning
- The conventional wisdom is that we should not do this, however this seems like a safe case to validate that conventional wisdom on. It will be good to have actual experience with this if we end up with a case where we are forced to do this.
- Deciding to wait to decide was the same as deciding to not do it as the costs only go up over time.
I hope we will have a longer discussion about this in the near future to sort out if this was actually a good idea and to what degree we want to allow this to be precedent.
Details
Below is the SHAs involved. I have pushed to my fork on github a backup branch for the state of the master we reverted and the three PRs who’s commits were reverted.
previous head: 85fd1aba15cb0bcffebf630d79d3cd1343246b98 (backup_master)
reverted to head: cb904b187370119e965e5fe811f796772647e7df
problematic commit: 62d8d65caab54dfb9daf41d0982fa58061adc6db
PRs that have to be re-done (with previous heads)
16437 :18d552d8b6172d3869b4d4791db6495b715f46cc (backup_16437)
16206 : c4d3cd4e797ab997df834fa02ef26f3299ee9682 (backup_16206)
8896 : 0492b885f0e97ce105e59958f705b6174539c6d5 (backup_8896)
jupiter@12:38 ➤ git push DANGER --force-with-lease
Total 0 (delta 0), reused 0 (delta 0)
To github.com:matplotlib/matplotlib.git
+ 85fd1aba1...cb904b187 master -> master (forced update)