How can I merge multiple commits onto another branch as a single squashed commit?

Question

I have a remote Git server, here is the scenario which I want to perform:

• For each bug/feature I create a different Git branch

• I keep on committing my code in that Git branch with un-official Git messages

• In top repository we have to do one commit for one bug with official Git message

So how can I merge my branch to remote branch so that they get just one commit for all my check-ins (I even want to provide commit message for this)?

Solution 1

Say your bug fix branch is called bugfix and you want to merge it into master:

git checkout master
git merge --squash bugfix
git commit

This will take all the commits from the bugfix branch, squash them into 1 commit, and merge it with your master branch.

---

Explanation:

git checkout master

Switches to your master branch.

git merge --squash bugfix

Takes all commits from the bugfix branch and groups it for a 1 commit with your current branch.
(no merge commit appears; you could resolve conflicts manually before following commit)

git commit

Creates a single commit from the merged changes.

Omitting the -m parameter lets you modify a draft commit message containing every message from your squashed commits before finalizing your commit.

Solution 2

What finally cleared this up for me was a comment showing that:

git checkout main
git merge --squash feature

is the equivalent of doing:

git checkout feature
git diff main > feature.patch
git checkout main
patch -p1 < feature.patch
git add .

When I want to merge a feature branch with 105(!!) commits and have them all squashed into one, I don't want to git rebase -i origin/master because I need to separately resolve merge conflicts for each of the intermediate commits (or at least the ones which git can't figure out itself). Using git merge --squash gets me the result I want, of a single commit for merging an entire feature branch. And, I only need to do at most one manual conflict resolution.

Solution 3

You want to merge with the squash option. That's if you want to do it one branch at a time.

git merge --squash feature1

If you want to merge all the branches at the same time as single commits, then first rebase interactively and squash each feature then octopus merge:

git checkout feature1
git rebase -i master

Squash into one commit then repeat for the other features.

git checkout master
git merge feature1 feature2 feature3 ...

That last merge is an "octopus merge" because it's merging a lot of branches at once.

Hope this helps

Solution 4

Merge newFeature branch into master with a custom commit:

git merge --squash newFeature && git commit -m 'Your custom commit message';

If instead, you do

git merge --squash newFeature && git commit

you will get a commit message that will include all the newFeature branch commits, which you can customize.

I explain it thoroughly here: https://youtu.be/FQNAIacelT4

Solution 5

If you have already git merge bugfix on main, you can squash your merge commit into one with:

git reset --soft HEAD^1
git commit

View more solutions

Comments

[Tyler]

I'm not sure if I completely understood you, but you may want an "octopus merge".

[poke]

Do you want to keep the individual commits on those other branches?

[Edward Falk]

I typically use git rebase -i to collapse all my commits into one commit and re-write the commit message. Then I send it upstream.

[Martin Thoma]

See also: What to do with branch after merge

[Martin Thoma]

@EdwardFalk What is the difference between git rebase -i and the (accepted) answer of abyx?

[Edward Falk]

git merge --squash does it all on the command line in one shot and you just hope it works. git rebase -i brings up an editor and lets you fine-tune the rebase. It's slower, but you can see what you're doing. Also, there are difference between rebase and merge which are a little too involved to address in a comment.

[Alexander Mills]

the problem with all these answers is that you have to be on the master branch locally and the run the merge --squash command... I want to run the merge --squash from the feature branch not the master branch..so that when I am done, I can push the feature branch to the remote and submit a PR, is that possible?

[Gyromite]

@AlexanderMills, I think you just need a second feature branch (cloned from the master branch). Do the merge --squash from the old to the new one, and then merge the new branch to master. The old branch becomes obsolete.

[Alex]

If you want to keep references to the old commit messages you can write git commit (without -m param) and you will get to modify a drafted commit message containing all commit messages that you squashed.

[Umair A.]

Why are you rebasing?

[andho]

@UmairAshraf it's an interactive rebase which gives you the option to do a squash within your branch.

[Janusz Lenar]

You can achieve the same by doing git commit --amend -m '...' later on.

[lowe0292]

@abyx I've been using your solution to move bugfixes and features from our develop to master as a single commit, but it appears that revert commits aren't being included in the merge squash. I'm cherry picking the revert commits as a workaround, but there's got to be a better solution for this corner case. Thoughts?

[dotancohen]

I highly suggest performing the merge in the feature branch first git merge master, and only then git merge --squash feature in the master branch.

[Dan Kohn]

Yes, one of the things that's great about the merge --squash strategy is that you can continually merge origin/master into your branch and it makes the eventual merge easier.

[bitsmack]

@dotancohen Sorry to dredge up an old comment :) What is gained from merging in the feature branch before performing git merge --squash feature from the master branch?

[Dan Kohn]

You want to merge master into the feature branch first, and deal with any manual fixes in your feature branch. That also lets you run tests and make sure your feature branch works correctly. Then, you are guaranteed that you can do an automatic merge of your feature branch into master.

[guntbert]

@dankohn I suggest you add the explanation in your above comment into your answer.

[Martin Thoma]

See also: Delete a Git branch both locally and remotely

[hdost]

If you have merge.ff=false in your config make sure to set --ff option

[Mike]

@bitsmack: you would merge master into feature first. This give you the opportunity to resolve conflicts on the feature before merging the feature into master

[Abdull]

In case merge conflicts happen and you resolve these conflicts, git commit will no longer show the useful commit message containing all commit messages you squashed. In that case, try git commit --file .git/SQUASH_MSG (via stackoverflow.com/a/11230783/923560 ).

[gaborous]

Keep in mind that squashing will by default attribute the commits to the squasher. To keep the original author, you need to explicitly specify it like so: git commit -a --author="Author" --message="Issue title #id"

[am0wa]

git merge --squash allows you to create a single commit on top of the current branch whose effect is the same as merging another branch. But it won't produce the merge record, which means your pull-request as result would have no changes, yet won't be marked as merged! So, you will need just to delete that branch to be done.

[Jesper Matthiesen]

git reset --soft HEAD^1 seems to undo the last commit performed before the merge, at least in case of the merge being a fast-forward.

[qwertzguy]

@JesperMatthiesen in case of a fast-forward you don't get a merge commit, so then you would do git reset --soft HEAD^<number-of-commits-to-squash>.

[killjoy]

This helped me to squash everything into a single commit after a downstream merge.

[Sebi2020]

Rebasing is a bad idea. Don't rebase already published commits

[Jordan Stefanelli]

@Melebius The only reference to "SourceTree" is in your sentence, if it was a tag or previous question: It doesn't exist anymore.

[Melebius]

@JordanStefanelli SourceTree was used in the original version of this answer. Thanks for notifying it’s fixed!

[xiix]

@Sebi2020 git merge --squash will rebase your already published commits in a way that's worse than an interactive rebase. An interactive rebase (on a feature branch) carry little to no adverse effects.

[Sebi2020]

@xiix This only holds true if you the only one working with the feature branch. This is not an assumption you can make. I recommend to read the pages related to rebasing on Git-SCM. It states "Do not rebase commits that exist outside your repository and people may have based work on them." And if you don't know for sure if people already based work on published commits (which you can't know because of the decentral nature of git) you shouln't do that.

[xiix]

@Sebi2020 - It's absolutely an assumption I can make. Not an assumption everyone can make, but at least in our company, we don't have massive amounts of people making uncoordinated changes off of feature branches.

[Luca Guidi]

GitHub uses the default email associated with your account. If you have multiple email addresses, and you need to use a secondary one, you can't use GH UI.

[Andrew Spencer]

@xiix @Sebi2020 Even when others have worked on the same branch, you can still rebase and force-push, at least in the case where their commits come after yours, and don't touch any lines on which you performed conflict resolution. When they git pull it will silently and successfully rebase their newer commits on top of your rebased ones. (Assuming they pull with the rebase option.)

[Craig Otis]

@am0wa This is a woefully under-mentioned aspect of --squash. When you do a merge --squash, you're NOT merging anything. You're creating a new commit, with the changes from the feature branch, but effectively abandoning that feature branch. Aside from the commit message of your "squash" commit, there's no reference within Git to the branch that was being "merged" in.

[actual_panda]

Would it be correct to say that git merge --squash && git commit does exactly the same as creating a merge commit, with the only difference that the resulting commit will only list one parent?

[ka3ak]

I think it would be more exactly to say that 'git merge --squash <branch>' puts all the changes from <branch> into the STAGED area of the current branch. After that you have to commit them explicitly.

[am0wa]

@Craig Otis of course. Rephrased the description. Just tried to kept it short. Many Thanks.

[ba11b0y]

Thanks @abyx, I just rolled out a production update with the help of this!

[leerssej]

Thank you for including the pull. All the other responses seem to assume that nothing has changed in the remote release branch since the last time you were hanging out on it....

[gebbissimo]

Do you have a link to the git source code that shows it really works this way? I've looked briefly here github.com/git/git/blob/master/builtin/merge.c , but haven't found the relevant part there

[alper]

Can I also do git merge --ff-only --squash dev ?

[Russo]

very relevant! Thanks!

[Ashish Sharma]

But when I ran theses commands, it give me message: "Squash commit -- not updating HEAD" Whats wrong here? I checked git log in feature branch which has some commits then it is not merging into develop branch? Does it not work for fork branches?

[KidCrippler]

@CraigOtis that's a great point. Anyway to have both? By both I mean committing the squashed code AND having an indication that the branch was merged (for PR/back tracking purposes).

[iuzuz]

Regarding "is the equivalent of doing..". There is an important difference if I remember correctly. On applying a patch, it's much more complicated to resolve conflicts. Because usually, no merge tool is used then.