Re: commit gone after merge - how to debug?

[ Jumping back in time ]

Igor Lautar <igor.lautar@gmail.com> writes:

My commands had the wrong order. It should have been git diff "$commit"^2 "$commit". So, it showed the reverse of the modification introduced by the commit. If you see your change here, it means the change was reverted by the merge.

My understanding of the situation up to now is:

M
|\
A C
|/
B

($commit = M, $commit^1 = A and $commit^2 = B)

Your file had a content (say, "old") at revision B. It changed content (say, to "new") at revision C, and at some point. A did not change it so it had the content "old". Then you merged, expected the merge commit M to get content "new", and actually got "old".

So, your history looks like:

M (old)
| \
|  `---.
|       \
A (old)  C (new)
|       /
|  .---'
| /
|/
B (old)

and "git diff C M" shows the diff between new and old.

Something went wrong during the merge, I guess it used an ancestor (B above) that had "new" as content. I don't see how this happened (rather clearly, your history is more complex than my example above), but "GIT_MERGE_VERBOSITY=5 git merge" will show you which common ancestor was used, it may help.

What's possible is that someone had already merged the branch containing "new", got conflicts, and resolved it in favor of "old" somewhere in the history of your master branch.