How to revert a merge commit that's already pushed to remote branch?

Question

git revert alone won\'t work. -m must be specified, and I\'m pretty confused about it.

Anyone experienced this before?<

Answer 1

I found good explanation for How To Revert The Merge from this link and I copy pasted the explanation below and it would be helpful just in case if below link doesn't work.

How to revert a faulty merge Alan(alan@clueserver.org) said:

I have a master branch. We have a branch off of that that some developers are doing work on. They claim it is ready. We merge it into the master branch. It breaks something so we revert the merge. They make changes to the code. they get it to a point where they say it is ok and we merge again. When examined, we find that code changes made before the revert are not in the master branch, but code changes after are in the master branch. and asked for help recovering from this situation.

The history immediately after the "revert of the merge" would look like this:

---o---o---o---M---x---x---W
              /
      ---A---B

where A and B are on the side development that was not so good, M is the merge that brings these premature changes into the mainline, x are changes unrelated to what the side branch did and already made on the mainline, and W is the "revert of the merge M" (doesn’t W look M upside down?). IOW, "diff W^..W" is similar to "diff -R M^..M".

Such a "revert" of a merge can be made with:

$ git revert -m 1 M After the developers of the side branch fix their mistakes, the history may look like this:

---o---o---o---M---x---x---W---x
              /
      ---A---B-------------------C---D

where C and D are to fix what was broken in A and B, and you may already have some other changes on the mainline after W.

If you merge the updated side branch (with D at its tip), none of the changes made in A or B will be in the result, because they were reverted by W. That is what Alan saw.

Linus explains the situation:

Reverting a regular commit just effectively undoes what that commit did, and is fairly straightforward. But reverting a merge commit also undoes the data that the commit changed, but it does absolutely nothing to the effects on history that the merge had. So the merge will still exist, and it will still be seen as joining the two branches together, and future merges will see that merge as the last shared state - and the revert that reverted the merge brought in will not affect that at all. So a "revert" undoes the data changes, but it's very much not an "undo" in the sense that it doesn't undo the effects of a commit on the repository history. So if you think of "revert" as "undo", then you're going to always miss this part of reverts. Yes, it undoes the data, but no, it doesn't undo history. In such a situation, you would want to first revert the previous revert, which would make the history look like this:

---o---o---o---M---x---x---W---x---Y
              /
      ---A---B-------------------C---D

where Y is the revert of W. Such a "revert of the revert" can be done with:

$ git revert W This history would (ignoring possible conflicts between what W and W..Y changed) be equivalent to not having W or Y at all in the history:

---o---o---o---M---x---x-------x----
              /
      ---A---B-------------------C---D

and merging the side branch again will not have conflict arising from an earlier revert and revert of the revert.

---o---o---o---M---x---x-------x-------*
              /                       /
      ---A---B-------------------C---D

Of course the changes made in C and D still can conflict with what was done by any of the x, but that is just a normal merge conflict.