G. Sylvie Davies venit, vidit, dixit 29.01.2017 07:45: > On Sat, Jan 28, 2017 at 6:28 AM, Jeff King <peff@xxxxxxxx> wrote: >> On Fri, Jan 27, 2017 at 09:42:41PM -0800, G. Sylvie Davies wrote: >> >>> Aside from the usual "git log -cc", I think this should work (replace >>> HEAD with whichever commit you are analyzing): >>> >>> git diff --name-only HEAD^2...HEAD^1 > m1 >>> git diff --name-only HEAD^1...HEAD^2 > b1 >>> git diff --name-only HEAD^1..HEAD > m2 >>> git diff --name-only HEAD^2..HEAD > b2 >>> >>> If files listed between m1 and b2 differ, then the merge is dirty. >>> Similarly for m2 and b1. >>> >>> More information here: >>> >>> http://stackoverflow.com/questions/27683077/how-do-you-detect-an-evil-merge-in-git/41356308#41356308 >> >> I don't think that can reliably find evil merges, since it looks at the >> file level. If you had one hunk resolved for "theirs" and one hunk for >> "ours" in a given file, then the file will be listed in each diff, >> whether it has evil hunks or not. >> > > Well, you have to do both. Do "git show -c" to catch that one > ("theirs" for one hunk, "ours" for the other, same file). > > And then do that sequence of the 4 "git diff" commands to identify > dirty merges where "theirs" or "ours" was applied to entire files, and > thus not showing up in the "git show -c". > >> I don't think this is just about evil merges, though. For instance, >> try: >> >> seq 1 10 >file >> git add file >> git commit -m base >> >> sed s/4/master/ <file >tmp && mv tmp file >> git commit -am master >> >> git checkout -b other HEAD^ >> sed s/4/other/ <file >tmp && mv tmp file >> git commit -am other >> >> git merge master >> git checkout --ours file >> git commit -am merged >> >> merge=$(git rev-parse HEAD) >> >> The question is: were there conflicts in $merge, and how were they >> resolved? >> >> That isn't an evil merge, but there's still something interesting to >> show that "git log --cc" won't display. >> >> Replaying the merge like: >> >> git checkout $merge^1 >> git merge $merge^2 >> git diff -R $merge >> >> shows you the patch to go from the conflict state to the final one. >> > > I know the stackoverflow question asks "how to detect evil merges", > and I go along with that in my answer. But honestly I prefer to call > them dirty rather than evil, and by "dirty" I just mean merges that > did not resolve cleanly via "git merge", and had some form of user > intervention, be it conflict resolution, or other strange things. > > The trick I propose with the sequence of 4 "git diff" commands > identifies that merge from your example as dirty: > > $ cat b1 m2 > file > > $ cat b2 m1 > file > file > > The trick doesn't really tell you much except that the merge is dirty. > If you notice that the "m2" file is empty, I think that's one way to > realize that master's edit was dropped, and therefore "other" won. > > Maybe it even merged cleanly but someone did a "git commit --amend" to > make it the merge dirty after the fact. > > I do like your approach, it's very simple and reliable. But in my > situation I'm writing pre-receive hooks for bare repos, so I don't > think I can actually do "git merge"! > > I think my suggestion would work for OP, as long as they also run "git > show -c" alongside it. (And your suggestion would work, too, of > course). If you're curious, I kept rebasing Thomas' remerge-diff (on top of our next) so far. You can find it at https://github.com/mjg/git/tree/remerge-diff if you're interested. I don't know what problems were found back then, or what it would take to get this in-tree now. Michael