I am using git as a version control system, and using git-flow as the branching model. I started a feature branch some weeks ago in order to maintain the system in a clean state while developping that feature. The main development continued on the develop branch, and changes from develop were merged periodically into the feature, to keep it up to date as much as possible.

However came the time where the feature was finished, and I used git-flow's finish feature to merge the feature back into develop. The merge was successfully done, but then I found out that some of the commits I made in develop were reverted by the merge commit!

Nowhere in develop or in the feature branch were these changes reverted, I can't see any commit that overwrote them. I just can't find anything. The only theory I have for the moment is that git is failing on me, but that would be extremely unlikely. Maybe I did some kind of wrong manipulation that made this situation come true?

I can trace back in the history when the commit was made. I can see that the changes from that commit were reverted by the merge commit. Nowhere in the branch I see a commit that reverts those changes. Yet they were reverted.

How is this even possible?