squashing-commits.md

What is squashing?

In git, squashing refers to rewriting the history of your commits, so you end up with one commit with a description of the changes done. It's usually done in open source projects because a lot of the history of a branch in open source projects is only relevant to the developer who created it, and this provides a simpler way to describe the changes made and also revert them if needed.

How do you squash commits?

First, perform a git log to review the commits you would like to merge in your current branch.

git log

You should see a series of your commits like so:

commit blablabla
Author: omguhh
Date:   10/10/20
    Commit message 1

commit blablabla2
Author: omguhh
Date:   10/10/20
    Commit message 2

So now that you see the commits you wish to merge to one, we can move along into doing that with git rebase. Assuming you're already familiar with git rebase, we can starting squashing commits in the interactive mode of git rebase that you can activate like so:

git rebase -i

Now, with interactive rebasing you can specify the starting and end point of how far back you want to go with commits like so:

git rebase -i HEAD~2

Running this command will show you something like the following:

pick blablabla Changing test01.txt file
pick blablabla2 Adding dummy01.txt file

#
# 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
#  x, exec = run command (the rest of the line) using shell
#
# These lines can be re-ordered; they are executed from top to bottom.
#
# If you remove a line here THAT COMMIT WILL BE LOST.
#
# However, if you remove everything, the rebase will be aborted.
#
# Note that empty commits are commented out

So if you want to squash blablabla2 into blablablabla, you would change the following :

pick blablabla Changing test01.txt file
squash blablabla2 Adding dummy01.txt file

If all goes well, you'd get a result that looks like this:

# This is a combination of 2 commits.
# The first commit's message is:
commit message 1

# This is the 2nd commit message:

commit message 2

That you can freely change before you decide to exit the editor to save these changes.

Running git log again should show you the commit message you entered before exiting the screen with the commits combined into one.