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

Question

git revert  lt commit hash gt  alone won t work  -m must be specified  and I m pretty confused about it   Anyone experienced this before

User · Answer

git doc about git revert -m provide a link exactly explain this  https   github com git git blob master Documentation howto revert-a-faulty-merge txt

User · Answer

The -m option specifies the parent number  This is because a merge commit has more than one parent  and Git does not know automatically which parent was the mainline  and which parent was the branch you want to un-merge   When you view a merge commit in the output of git log  you will see its parents listed on the line that begins with Merge   commit 8f937c683929b08379097828c8a04350b9b8e183 Merge  8989ee0 7c6b236 Author  Ben James  lt ben example com gt  Date    Wed Aug 17 22 49 41 2011  0100  Merge branch  gh-pages   Conflicts      README   In this situation  git revert 8f937c6 -m 1 will get you the tree as it was in 8989ee0  and git revert -m 2 will reinstate the tree as it was in 7c6b236   To better understand the parent IDs  you can run   git log 8989ee0    and   git log 7c6b236

User · Answer

If you want to revert a merge commit  here is what you have to do    First  check the git log to find your merge commit s id  You ll also find multiple parent ids associated with the merge  see image below       Note down the merge commit id shown in yellow  The parent IDs are the ones written in the next line as Merge  parent1 parent2  Now     Short Story    Switch to branch on which the merge was made  Then Just do the git revert  lt merge commit id gt  -m 1 which will open a vi console for entering commit message  Write  save  exit  done    Long story    Switch to branch on which the merge was made  In my case  it is the test branch and I m trying to remove the feature analytics-v3 branch from it  git revert is the command which reverts any commit  But there is a nasty trick when reverting a merge commit  You need to enter the -m flag otherwise it will fail  From here on  you need to decide whether you want to revert your branch and make it look like exactly it was on parent1 or parent2 via    git revert  lt merge commit id gt  -m 1  reverts to parent2   git revert  lt merge commit id gt  -m 2  reverts to parent1   You can git log these parents to figure out which way you want to go and that s the root of all the confusion

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The correctly marked answer worked for me but I had to spend some time to determine whats going on   So I decided to add an answer with simple straightforward steps for cases like mine    Lets say we got branches A and B   You merged branch A into branch B and pushed branch B to itself so now the merge is part of it   But you want to go back to the last commit before the merge   What do you do    Go to your git root folder  the project folder usually  and use git log You will see the history of recent commits - the commits have commit author date properties while the merges also have a merge property - so you see them like this   commit   lt commitHash gt   Merge   lt parentHashA gt   lt parentHashB gt   Author   lt author gt   Date   lt date gt  Use git log  lt parentHashA gt  and git log  lt parentHashB gt  - you will see the commit histories of those parent branches - the first commits in the list are the latest ones Take the  lt commitHash gt  of the commit you want  go to your git root folder and use git checkout -b  lt newBranchName gt   lt commitHash gt  - that will create a new branch starting from that last commit you ve chosen before the merge   Voila  ready

User · Answer

All the answers already covered most of the things but I will add my 5 cents  In short reverting a merge commit is quite simple   git revert -m 1  lt commit-hash gt    If you have permission you can push it directly to the  master  branch otherwise simply push it to your  revert  branch and create pull request   You might find more useful info on this subject here  https   itcodehub blogspot com 2019 06 how-to-revert-merge-in-git html

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I found creating a reverse patch between two know end-points and applying that patch would work  This presumes that you have created snapshots  tags  off of your master branch or even a back up of your master branch say master bk 01012017   Say the code branch you merged into master was mycodebranch    Checkout master  Create a full binary reverse patch between master and your backup  git diff --binary master  master bk 01012017     myrevert patch Check your patch git apply --check myrevert patch Apply patch with sign-off git am --signoff  lt  myrevert patch If you will need to bring in this code again once it is fixed  you will need to branch off the reverted master and checkout the fix branch git branch mycodebranch fix git checkout mycodebranch fix Here you need to find the SHA key for the revert and revert the revert git revert  SHA  Now you can use your mycodebranch fix to fix the issues  commit and re-merge into master once done

User · Answer

I also faced this issue on a PR that has been merged to the master branch of a GitHub repo   Since I just wanted to modify some modified files but not the whole changes the PR brought  I had to amend the merge commit with git commit --am   Steps    Go to the branch which you want to change   revert some modified files Do the changes you want according to modified files run git add   or git add  lt file gt  run git commit --am and validate run git push -f   Why it s interesting    It keeps the PR s author commit unchanged It doesn t break the git tree You ll be marked as committer  merge commit author will remain unchanged  Git act as if you resolved conflicts  it will remove   change the code in modified files as if you manually tell GitHub to not merge it as-is

User · Answer

git revert -m 1  lt merge-commit gt

User · Answer

This is a very old thread  but I am missing another in my opinion convenient solution  I never revert a merge  I just create another branch from the revision where everything was ok and then cherry pick everything that needs to picked from the old branch which was added in between  So  if the GIT history is like this   d c b  lt  lt  lt  the merge a      I create a new branch from a  cherry pick c and d and then the new branch is clear from b  I can ever decide to do the merge of  quot b quot  in my new branch again  The old branch becomes deprecated and will be deleted if  quot b quot  is not necessary anymore or still in another  feature hotfix  branch  The only problem is now one of the very hardest things in computer science  How do you name the new branch     Ok  if you failed esp  in devel  you create newdevel as mentioned above  delete old devel and rename newdevel to devel  Mission accomplished  You can now merge the changes again when you want  It is like never merged before

User · Answer

Ben has told you how to revert a merge commit  but it s very important you realize that in doing so          declares that you will never want the tree changes brought in by the merge  As a result  later merges will only bring in tree changes introduced by commits that are not ancestors of the previously reverted merge  This may or may not be what you want    git-merge man page     An article mailing list message linked from the man page details the mechanisms and considerations that are involved  Just make sure you understand that if you revert the merge commit  you can t just merge the branch again later and expect the same changes to come back

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Sometimes the most effective way to rollback is to step back and replace   git log  Use the 2nd commit hash  full hash  the one you want to revert back to  before the mistake listed  and then rebranch from there   git checkout -b newbranch  lt HASH gt   Then delete the old branch  copy the newbranch over in its place and restart from there   git branch -D oldbranch git checkout -b oldbranch newbranch   If its been broadcast  then delete the old branch from all repositories  push the redone branch to the most central  and pull it back down to all

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As Ryan mentioned  git revert could make merging difficult down the road  so git revert may not be what you want  I found that using the git reset --hard  lt commit-hash-prior-to-merge gt  command to be more useful here   Once you have done the hard reset part  you can then force push to the remote branch  i e  git push -f  lt remote-name gt   lt remote-branch-name gt   where  lt remote-name gt  is often named origin  From that point you can re-merge if you d like

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-m1 is the last parent of the current branch that is being fixed  -m 2 is the original parent of the branch that got merged into this  Tortoise Git can also help here if command line is confusing

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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

User · Answer

You could follow these steps to revert the incorrect commit s  or to reset your remote branch back to correct HEAD state    checkout the remote branch to local repo  git checkout development copy the commit hash  i e  id of the commit immediately before the wrong commit  from git log git log -n5     output        commit 7cd42475d6f95f5896b6f02e902efab0b70e8038  Merge branch  wrong-commit  into  development      commit f9a734f8f44b0b37ccea769b9a2fd774c0f0c012  this is a wrong commit     commit 3779ab50e72908da92d2cfcd72256d7a09f446ba  this is the correct commit   reset the branch to the commit hash copied in the previous step  git reset  lt commit-hash gt   i e  3779ab50e72908da92d2cfcd72256d7a09f446ba  run the git status to show all the changes that were part of the wrong commit  simply run git reset --hard to revert all those changes  force-push your local branch to remote and notice that your commit history is clean as it was before it got polluted  git push -f origin development

User · Answer

A very simple answer if you are looking to revert the change that you pushed just now   commit 446sjb1uznnmaownlaybiosqwbs278q87 Merge  123jshc 90asaf   git revert -m 2 446sjb1uznnmaownlaybiosqwbs278q87   does the work

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Here s a complete example in the hope that it helps someone   git revert -m 1  lt commit-hash gt   git push -u origin master   Where  lt commit-hash gt  is the commit hash of the merge that you would like to revert  and as stated in the explanation of this answer  -m 1 indicates that you d like to revert to the tree of the first parent prior to the merge   The git revert     line essentially commits your changes while the second line makes your changes public by pushing them to the remote branch

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To keep the log clean as nothing happened  with some downsides with this approach  due to push -f     git checkout  lt branch gt  git reset --hard  lt commit-hash-before-merge gt  git push -f origin HEAD  lt remote-branch gt     commit-hash-before-merge  comes from the log  git log  after merge

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

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