On Thu, May 30, 2019 at 9:19 PM Bryan Turner <bturner@xxxxxxxxxxxxx> wrote: > > I was looking through the commit history in a repository I work in and > I found a place where someone had created a merge, but somewhere > between "git merge" and "git commit" the fact that it was a merge was > "lost". Instead they ended up with a really big commit that applied > all the changes from the merged-in branch. > > A really easy way to reproduce this is: > git merge master #Assume this has conflicts, or use --no-commit > git checkout -b some-new-branch > > When the checkout runs, MERGE_HEAD et al are deleted without any sort > of warning, but the uncommitted changes are not lost. If a user then > runs "git commit", and doesn't notice that there's no helpful "It > looks like you may be committing a merge", they'll create a new, > non-merge commit that essentially reapplies all the changes they > merged in. > > I'm pretty familiar with Git and I make this mistake at least a few > times a year. So far I've always caught it during the commit, though. > Unfortunately, in this case, the bad "merge" wasn't noticed before it > made its way to master, so now it's there for good. > > I'm not sure what there is to do about this. It's clear it's a > long-standing behavior. One approach might be to introduce a warning > when changing branches deletes MERGE_*. A different one might be to > fail to change branches without something like --force. I'm not sure > either is _better_ than the current behavior, but they're certainly > _clearer_. That said, perhaps this behavior is something someone > relies on. > > Best regards, > Bryan Turner Discussed in detail recently starting at https://public-inbox.org/git/CACsJy8Axa5WsLSjiscjnxVK6jQHkfs-gH959=YtUvQkWriAk5w@xxxxxxxxxxxxxx/ resulting in https://public-inbox.org/git/20190329103919.15642-8-pclouds@xxxxxxxxx/ and https://public-inbox.org/git/20190329103919.15642-24-pclouds@xxxxxxxxx/ I think we should still do the follow up for checkout, as mentioned at https://public-inbox.org/git/CABPp-BHX1gRhTdurAwrPg60Hk-OuhbrEN=4zatx4OOUo-DkQvw@xxxxxxxxxxxxxx/ It's good to get extra feedback that this isn't just theoretical but is causing people actual problems. Do you want to take the time to make the change I suggested in the last email above and propose it to the list? I think the main thing needed is just a good commit message and getting feedback and thoughts from others; your description above was well written and I'm busy on other things right now, so if you'd like to tackle it, I'd appreciate it. If not, I will hopefully remember to get back to it eventually. Hope that helps, Elijah
