How can I merge two commits into one if I already started rebase

Question

I am trying to merge 2 commits into 1  so I followed  ldquo squashing commits with rebase rdquo  from git ready   I ran  git rebase --interactive HEAD 2   In the resulting editor  I change pick to squash and then save-quit  but the rebase fails with the error     Cannot  squash  without a previous commit   Now that my work tree has reached this state  I rsquo m having trouble recovering      The command git rebase --interactive HEAD 2 fails with      Interactive rebase already started   and git rebase --continue fails with     Cannot  squash  without a previous commit

User · Answer

If you want to combine the two most recent commits and just use the older commit's message, you can automate the process using expect.

I assume:

You're using vi as your editor
Your commits are one-line each

I tested with git version 2.14.3 (Apple Git-98).

#!/usr/bin/env expect
spawn git rebase -i HEAD~2

# change the second "pick" to "squash"
# down, delete word, insert 's' (for squash), Escape, save and quit
send "jdwis \033:wq\r"

expect "# This is a"

# skip past first commit message (assumed to be one line), delete rest of file
# down 4, delete remaining lines, save and quit
send "4jdG\r:wq\r"

interact

User · Answer

Assuming you were in your own topic branch   If you want to merge the last 2 commits into one and look like a hero  branch off the commit just before you made the last two commits  specified with the relative commit name HEAD 2   git checkout -b temp branch HEAD 2  Then squash commit the other branch in this new branch  git merge branch with two commits --squash  That will bring in the changes but not commit them   So just commit them and you re done  git commit -m  quot my message quot   Now you can merge this new topic branch back into your main branch

User · Answer

Summary  The error message     Cannot  squash  without a previous commit   means you likely attempted to    squash downward     Git always squashes a newer commit into an older commit or    upward    as viewed on the interactive rebase todo list  that is into a commit on a previous line  Changing the command on your todo list   s very first line to squash will always produce this error as there is nothing for the first commit to squash into   The Fix  First get back to where you started with    git rebase --abort   Say your history is    git log --pretty oneline a931ac7c808e2471b22b5bd20f0cad046b1c5d0d c b76d157d507e819d7511132bdb5a80dd421d854f b df239176e1a2ffac927d8b496ea00d5488481db5 a   That is  a was the first commit  then b  and finally c  After committing c we decide to squash b and c together    Note  Running git log pipes its output into a pager  less by default on most platforms  To quit the pager and return to your command prompt  press the q key    Running git rebase --interactive HEAD 2 gives you an editor with  pick b76d157 b pick a931ac7 c    Rebase df23917  a931ac7 onto df23917     Commands     p  pick   use commit    r  reword   use commit  but edit the commit message    e  edit   use commit  but stop for amending    s  squash   use commit  but meld into previous commit    f  fixup   like  squash   but discard this commit s log message     If you remove a line here THAT COMMIT WILL BE LOST    However  if you remove everything  the rebase will be aborted       Notice that this todo list is in the reverse order as compared with the output of git log    Changing b   s pick to squash will result in the error you saw  but if instead you squash c into b  newer commit into the older or    squashing upward     by changing the todo list to  pick   b76d157 b squash a931ac7 c   and save-quitting your editor  you ll get another editor whose contents are    This is a combination of 2 commits    The first commit s message is   b    This is the 2nd commit message   c   When you save and quit  the contents of the edited file become commit message of the new combined commit     git log --pretty oneline 18fd73d3ce748f2a58d1b566c03dd9dafe0b6b4f b and c df239176e1a2ffac927d8b496ea00d5488481db5 a   Note About Rewriting History  Interactive rebase rewrites history  Attempting to push to a remote that contains the old history will fail because it is not a fast-forward   If the branch you rebased is a topic or feature branch in which you are working by yourself  no big deal  Pushing to another repository will require the --force option  or alternatively you may be able  depending on the remote repository   s permissions  to first delete the old branch and then push the rebased version  Examples of those commands that will potentially destroy work is outside the scope of this answer   Rewriting already-published history on a branch in which you are working with other people without very good reason such as leaking a password or other sensitive details forces work onto your collaborators and is antisocial and will annoy other developers  The    Recovering From an Upstream Rebase    section in the git rebase documentation explains  with added emphasis      Rebasing  or any other form of rewriting  a branch that others have based work on is a bad idea  anyone downstream of it is forced to manually fix their history  This section explains how to do the fix from the downstream   s point of view  The real fix  however  would be to avoid rebasing the upstream in the first place   hellip

User · Answer

I often use git reset --mixed to revert a base version before multiple commits which you want to merge  then I make a new commit  that way could let your commit newest  assure your version is HEAD after you push to server   commit ac72a4308ba70cc42aace47509a5e Author   lt me me com gt  Date    Tue Jun 11 10 23 07 2013  0500      Added algorithms for Cosine-similarity  commit 77df2a40e53136c7a2d58fd847372 Author   lt me me com gt  Date    Tue Jun 11 13 02 14 2013 -0700      Set stage for similar objects  commit 249cf9392da197573a17c8426c282 Author  Ralph  lt ralph me com gt  Date    Thu Jun 13 16 44 12 2013 -0700      Fixed a bug in space world automation   If I want to merge head two commits into one  first I use     git reset --mixed 249cf9392da197573a17c8426c282    249cf9392da197573a17c8426c282  was third version  also is your base version before you merge  after that  I make a new commit    git add   git commit -m  some commit message    It s all  hope is another way for everybody   FYI  from git reset --help    --mixed      Resets the index but not the working tree  i e   the changed files are      preserved but not marked for commit  and reports what has not been      updated  This is the default action

User · Answer

First you should check how many commits you have   git log   There are two status   One is that there are only two commits   For example   commit A commit B    In this case  you can t use git rebase to do  you need to do following      git reset --soft HEAD 1    git commit --amend   Another is that there are more than two commits  you want to merge commit C and D   For example   commit A commit B commit C commit D    under this condition  you can use git rebase   git rebase -i B   And than use  squash  to do  The rest thins is very easy  If you still don t know  please read http   zerodie github io blog 2012 01 19 git-rebase-i

User · Answer

If there are multiple commits  you can use git rebase -i to squash two commits into one   If there are only two commits you want to merge  and they are the  most recent two   the following commands can be used to combine the two commits into one   git reset --soft  HEAD   git commit --amend

User · Answer

If your master branch git log looks something like following   commit ac72a4308ba70cc42aace47509a5e Author   lt me me com gt  Date    Tue Jun 11 10 23 07 2013  0500      Added algorithms for Cosine-similarity  commit 77df2a40e53136c7a2d58fd847372 Author   lt me me com gt  Date    Tue Jun 11 13 02 14 2013 -0700      Set stage for similar objects  commit 249cf9392da197573a17c8426c282 Author  Ralph  lt ralph me com gt  Date    Thu Jun 13 16 44 12 2013 -0700      Fixed a bug in space world automation   and you want to merge the top two commits just do following easy steps    First to be on safe side checkout the second last commit in a separate branch  You can name the branch anything  git checkout 77df2a40e53136c7a2d58fd847372 -b merged-commits Now  just cherry-pick your changes from the last commit into this new branch as  git cherry-pick -n -x ac72a4308ba70cc42aace47509a5e   Resolve conflicts if arise any  So now  your changes in last commit are there in your second last commit  But you still have to commit  so first add the changes you just cherry-picked and then execute git commit --amend    That s it  You may push this merged version in branch  merged-commits  if you like   Also  you can discard the back-to-back two commits in your master branch now  Just update your master branch as   git checkout master git reset --hard origin master  CAUTION  This command will remove any local changes to your master branch  git pull

User · Answer

Since I use git cherry-pick for just about everything  to me it comes natural to do so even here   Given that I have branchX checked out and there are two commits at the tip of it  of which I want to create one commit combining their content  I do this   git checkout HEAD     Checkout the privious commit git cherry-pick --no-commit branchX    Cherry pick the content of the second commit git commit --amend    Create a new commit with their combined content   If i want to update branchX as well  and I suppose this is the down side of this method  I also have to   git checkout branchX git reset --hard  lt the new commit gt

User · Answer

Rebase  You Ain t Gonna Need It   A simpler way for most frequent scenario   In most cases   Actually if all you want is just simply combine several recent commits into one  but do not need drop  reword and other rebase work    you can simply do   git reset --soft  HEAD n     Assuming  n is number of commits to softly un-commit  i e   1   2        Then  use following command to modify the commit message   git commit --amend   which is pretty much the same as a long range of squash and one pick   And it works for n commits but not just two commits as above answer prompted

User · Answer

git rebase --abort  Run this code at any time if you want to undo the git rebase    git rebase -i HEAD 2  To reapply last two commits  The above command will open a code editor     The latest commit will be at the bottom    Change the last commit to squash s   Since squash will meld with previous commit  Then press esc key and type  wq to save and close   After  wq you will be in active rebase mode  Note  You ll get another editor if no warning error messages  If there is an error or warning another editor will not show  you may abort by runnning    git rebase --abort if you see an error or warning else just continue by running   git rebase --continue  You will see your 2 commit message  Choose one or write your own commit message  save and quit   wq   Note 2  You may need to force push your changes to the remote repo if you run rebase command    git push -f      git push -f origin master

User · Answer

Let me suggest you an easier approach  Instead of divind into GIT s deep consepts and bothering with the editor s crab  you could do the following  Lets suppose you created a branch named bug1 from master  Made 2 commits to bug1  You only modified 2 files with these changes  Copy these two files into a text editor  Checkout master  Paste the files  Commit  That simple

User · Answer

you can cancel the rebase with  git rebase --abort   and when you run the interactive rebase command again the  squash  commit must be below the pick commit in the list

[git] How can I merge two commits into one if I already started rebase?

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