Break a previous commit into multiple commits

Question

Without creating a branch and doing a bunch of funky work on a new branch  is it possible to break a single commit into a few different commits after it s been committed to the local repository

User · Answer

I think that the best way i use git rebase -i  I created a video to show the steps to split a commit  https   www youtube com watch v 3EzOz7e1ADI

User · Answer

git rebase --interactive can be used to split a commit into smaller commits   The Git docs on rebase have a concise walkthrough of the process - Splitting Commits   In interactive mode  you can mark commits with the action  quot edit quot   However  this does not necessarily mean that git rebase expects the result of this edit to be exactly one commit  Indeed  you can undo the commit  or you can add other commits  This can be used to split a commit into two   Start an interactive rebase with git rebase -i  lt commit gt    where  lt commit gt  is the commit you want to split  In fact  any commit range will do  as long as it contains that commit   Mark the commit you want to split with the action  quot edit quot    When it comes to editing that commit  execute git reset HEAD   The effect is that the HEAD is rewound by one  and the index follows suit  However  the working tree stays the same   Now add the changes to the index that you want to have in the first commit  You can use git add  possibly interactively  or git gui  or both  to do that   Commit the now-current index with whatever commit message is appropriate now   Repeat the last two steps until your working tree is clean   Continue the rebase with git rebase --continue    If you are not absolutely sure that the intermediate revisions are consistent  they compile  pass the testsuite  etc   you should use git stash to stash away the not-yet-committed changes after each commit  test  and amend the commit if fixes are necessary

User · Answer

You can do interactive rebase git rebase -i  Man page has exactly what you want   http   git-scm com docs git-rebase  splitting commits

User · Answer

git rebase -i will do it   First  start with a clean working directory  git status should show no pending modifications  deletions  or additions   Now  you have to decide which commit s  you want to split   A  Splitting the most recent commit  To split apart your most recent commit  first     git reset HEAD    Now commit the pieces individually in the usual way  producing as many commits as you need   B  Splitting a commit farther back  This requires rebasing  that is  rewriting history  To find the correct commit  you have several choices    If it was three commits back  then    git rebase -i HEAD 3   where 3 is how many commits back it is  If it was farther back in the tree than you want to count  then    git rebase -i 123abcd    where 123abcd is the SHA1 of the commit you want to split up  If you are on a different branch  e g   a feature branch  that you plan to merge into master     git rebase -i master    When you get the rebase edit screen  find the commit you want to break apart   At the beginning of that line  replace pick with edit  e for short    Save the buffer and exit   Rebase will now stop just after the commit you want to edit   Then     git reset HEAD    Commit the pieces individually in the usual way  producing as many commits as you need  then    git rebase --continue

User · Answer

Now in the latest TortoiseGit on Windows you can do it very easily   Open the rebase dialog  configure it  and do the following steps    Right-click the commit you want to split and select  Edit   among pick  squash  delete        Click  Start  to start rebasing    Once it arrives to the commit to split  check the  Edit Split  button and click on  Amend  directly  The commit dialog opens   Unselect the files you want to put on a separate commit  Edit the commit message  and then click  commit     Until there are files to commit  the commit dialog will open again and again  When there is no more file to commit  it will still ask you if you want to add one more commit    Very helpful  thanks TortoiseGit

User · Answer

It s been more than 8 years  but maybe someone will find it helpful anyway  I was able to do the trick without rebase -i  The idea is to lead git to the same state it was before you did git commit     first rewind back  mind the dot    though it can be any valid path    for instance if you want to apply only a subset of the commit  git reset --hard  lt previous-commit gt       apply the changes git checkout  lt commit-you-want-to-split gt     we re almost there  but the changes are in the index at the moment    hence one more step  exactly as git gently suggests      use  git reset HEAD  lt file gt      to unstage  git reset   After this you ll see this shiny Unstaged changes after reset  and your repo is in a state like you re about to commit all these files  From now on you can easily commit it again like you usually do  Hope it helps

User · Answer

If you have this   A - B  lt - mybranch   Where you have committed some content in commit B    modules a file1  modules a file2  modules b file3  modules b file4   But you want to split B into C - D  and get this result   A - C - D  lt -mybranch   You can divide the content like this for example  content from different directories in different commits      Reset the branch back to the commit before the one to split   git checkout mybranch git reset --hard A   Create first commit  C    git checkout B  modules a git add -u git commit -m  content of  modules a    Create second commit  D    git checkout B  modules b git add -u git commit -m  content of  modules b

User · Answer

A quick reference of the necessary commands  because I basically know what to do but always forget the right syntax   git rebase -i  lt sha1 before split gt    mark the targeted commit with  edit  git reset HEAD  git add     git commit -m  First part  git add     git commit -m  Second part  git rebase --continue   Credits to Emmanuel Bernard s blog post

User · Answer

From git-rebase manual  SPLITTING COMMITS section   In interactive mode  you can mark commits with the action  quot edit quot   However  this does not necessarily mean that git rebase expects the result of this edit to be exactly one commit  Indeed  you can undo the commit  or you can add other commits  This can be used to split a commit into two   Start an interactive rebase with git rebase -i  lt commit gt    where  lt commit gt  is the commit you want to split  In fact  any commit range will do  as long as it contains that commit   Mark the commit you want to split with the action  quot edit quot    When it comes to editing that commit  execute git reset HEAD   The effect is that the HEAD is rewound by one  and the index follows suit  However  the working tree stays the same   Now add the changes to the index that you want to have in the first commit  You can use git add  possibly interactively  or git gui  or both  to do that   Commit the now-current index with whatever commit message is appropriate now   Repeat the last two steps until your working tree is clean   Continue the rebase with git rebase --continue

User · Answer

Previous answers have covered the use of git rebase -i to edit the commit that you want to split  and committing it in parts   This works well when splitting the files into different commits  but if you want to break apart changes to the individual files  there s more you need to know   Having got to the commit you want to split  using rebase -i and marking it for edit  you have two options    After using git reset HEAD   go through the patches individually using git add -p to select the ones you want in each commit Edit the working copy to remove the changes you do not want  commit that interim state  and then pull back the full commit for the next round    Option 2 is useful if you re splitting a large commit  as it lets you check that the interim versions build and run properly as part of the merge  This proceeds as follows   After using rebase -i and editing the commit  use  git reset --soft HEAD    to undo the commit  but leave the committed files in the index  You can also do a mixed reset by omitting --soft  depending on how close to the final result your initial commit is going to be  The only difference is whether you start with all the changes staged or with them all unstaged   Now go in and edit the code  You can remove changes  delete added files  and do whatever you want to construct the first commit of the series you re looking for  You can also build it  run it  and confirm that you have a consistent set of source   Once you re happy  stage unstage the files as needed  I like to use git gui for this   and commit the changes through the UI or the command line  git commit   That s the first commit done  Now you want to restore your working copy to the state it had after the commit you are splitting  so that you can take more of the changes for your next commit  To find the sha1 of the commit you re editing  use git status  In the first few lines of the status you ll see the rebase command that is currently executing  in which you can find the sha1 of your original commit     git status interactive rebase in progress  onto be83b41 Last commands done  3 commands done      pick 4847406 US135756  add debugging to the file download code    e 65dfb6a US135756  write data and download from remote    see more in file  git rebase-merge done        In this case  the commit I m editing has sha1 65dfb6a  Knowing that  I can check out the content of that commit over my working directory using the form of git checkout which takes both a commit and a file location  Here I use   as the file location to replace the whole working copy   git checkout 65dfb6a     Don t miss the dot on the end   This will check out  and stage  the files as they were after the commit you re editing  but relative to the previous commit you made  so any changes you already committed won t be part of the commit   You can either go ahead now and commit it as-is to finish the split  or go around again  deleting some parts of the commit before making another interim commit   If you want to reuse the original commit message for one or more commits  you can use it straight from the rebase s working files   git commit --file  git rebase-merge message   Finally  once you ve committed all the changes    git rebase --continue   will carry on and complete the rebase operation

User · Answer

Please note there s also git reset --soft HEAD   It s similar to git reset  which defaults to --mixed  but it retains the index contents  So that if you ve added removed files  you have them in the index already   Turns out to be very useful in case of giant commits

User · Answer

This method is most useful if your changes were mostly adding new content  Sometimes you do not want to lose commit message associated with commit that is being split  If you have commited some changes that you want to split  you can   Edit the changes you want removed out of the file  ie delete the lines or change the files approprietely to fit into first commit   You can use combination of your chosen editor and git checkout -p HEAD  -- path to file to revert some changes into current tree  Commit this edit as a new commit  with something like git add     git commit -m  removal of things that should be changed later   so you will have original commit in history and you will also have another commit with changes that you made  so the files on current HEAD look like you would want them in first commit after splitting   000aaa Original commit 000bbb removal of things that should be changed later   Revert the edit with git revert HEAD  this will create revert commit  Files will look like they do on original commit and your history will now look like  000aaa Original commit 000bbb removal of things that should be changed later 000ccc Revert  quot removal of things that should be changed later quot   assuming you didn t edit commit message immediately    Now  you can squash fixup first two commits into one with git rebase -i  optionally amend revert commit if you didn t give meaningful commit message to it earlier  You should be left with  000ddd Original commit  but without some content that is changed later 000eee Things that should be changed later

User · Answer

Here is how to split one commit in IntelliJ IDEA  PyCharm  PhpStorm etc   In Version Control log window  select the commit you would like to split  right click and select the Interactively Rebase from Here   mark the one you want to split as edit  click Start Rebasing You should see a yellow tag is placed meaning that the HEAD is set to that commit  Right click on that commit  select Undo Commit Now those commits are back to staging area  you can then commit them separately  After all change has been committed  the old commit becomes inactive

User · Answer

Use git rebase --interactive to edit that earlier commit  run git reset HEAD   and then git add -p to add some  then make a commit  then add some more and make another commit  as many times as you like  When you re done  run git rebase --continue  and you ll have all the split commits earlier in your stack   Important  Note that you can play around and make all the changes you want  and not have to worry about losing old changes  because you can always run git reflog to find the point in your project that contains the changes you want   let s call it a8c4ab   and then git reset a8c4ab   Here s a series of commands to show how it works   mkdir git-test  cd git-test  git init  now add a file A  vi A  add this line   one  git commit -am one  then add this line to A   two  git commit -am two  then add this line to A   three  git commit -am three  now the file A looks like this   one two three   and our git log looks like the following  well  I use git log --pretty oneline --pretty   h  cn  cr ----  s   bfb8e46 Rose Perrone 4 seconds ago ---- three 2b613bc Rose Perrone 14 seconds ago ---- two 9aac58f Rose Perrone 24 seconds ago ---- one   Let s say we want to split the second commit  two   git rebase --interactive HEAD 2  This brings up a message that looks like this   pick 2b613bc two pick bfb8e46 three   Change the first pick to an e to edit that commit   git reset HEAD   git diff shows us that we just unstaged the commit we made for the second commit   diff --git a A b A index 5626abf  814f4a4 100644 --- a A     b A    -1  1 2     one  two   Let s stage that change  and add  and a third  to that line in file A   git add    This is usually the point during an interactive rebase where we would run git rebase --continue  because we usually just want to go back in our stack of commits to edit an earlier commit  But this time  we want to create a new commit  So we ll run git commit -am  two and a third   Now we edit file A and add the line two and two thirds    git add   git commit -am  two and two thirds  git rebase --continue  We have a conflict with our commit  three  so let s resolve it   We ll change  one  lt  lt  lt  lt  lt  lt  lt  HEAD two and a third two and two thirds         two three  gt  gt  gt  gt  gt  gt  gt  bfb8e46    three   to   one two and a third two and two thirds three   git add    git rebase --continue  Now our git log -p looks like this   commit e59ca35bae8360439823d66d459238779e5b4892 Author  Rose Perrone  lt roseperrone fake com gt  Date    Sun Jul 7 13 57 00 2013 -0700      three  diff --git a A b A index 5aef867  dd8fb63 100644 --- a A     b A    -1 3  1 4     one  two and a third  two and two thirds  three  commit 4a283ba9bf83ef664541b467acdd0bb4d770ab8e Author  Rose Perrone  lt roseperrone fake com gt  Date    Sun Jul 7 14 07 07 2013 -0700      two and two thirds  diff --git a A b A index 575010a  5aef867 100644 --- a A     b A    -1 2  1 3     one  two and a third  two and two thirds  commit 704d323ca1bc7c45ed8b1714d924adcdc83dfa44 Author  Rose Perrone  lt roseperrone fake com gt  Date    Sun Jul 7 14 06 40 2013 -0700      two and a third  diff --git a A b A index 5626abf  575010a 100644 --- a A     b A    -1  1 2     one  two and a third  commit 9aac58f3893488ec643fecab3c85f5a2f481586f Author  Rose Perrone  lt roseperrone fake com gt  Date    Sun Jul 7 13 56 40 2013 -0700      one  diff --git a A b A new file mode 100644 index 0000000  5626abf ---  dev null     b A    -0 0  1     one

User · Answer

Easiest thing to do without an interactive rebase is  probably  to make a new branch starting at the commit before the one you want to split  cherry-pick -n the commit  reset  stash  commit the file move  reapply the stash and commit the changes  and then either merge with the former branch or cherry-pick the commits that followed    Then switch the former branch name to the current head     It s probably better to follow MBOs advice and do an interactive rebase

User · Answer

If you just want to extract something from existing commit and keep the original one  you can use git reset --patch HEAD   instead of git reset HEAD   This command allows you to reset just chunks you need  After you chose the chunks you want to reset  you ll have staged chunks that will reset changes in previous commit after you do git commit --amend --no-edit  and unstaged chunks that you can add to the separate commit by git add   git commit -m  quot new commit quot   Off topic fact  In mercurial they have hg split - the second feature after hg absorb I d like to see in git

[git] Break a previous commit into multiple commits

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