使用 Git 压缩我最后的多次提交为一次提交

如何使用 Git 将我的最后多次的提交合并为一次提交?

You can do this fairly easily without git rebase or git merge --squash. In this example, we'll squash the last 3 commits.

If you want to write the new commit message from scratch, this suffices:

git reset --soft HEAD~3 &&
git commit

If you want to start editing the new commit message with a concatenation of the existing commit messages (i.e. similar to what a pick/squash/squash/…/squash git rebase -i instruction list would start you with), then you need to extract those messages and pass them to git commit:

git reset --soft HEAD~3 && 
git commit --edit -m"$(git log --format=%B --reverse HEAD..HEAD@{1})"

Both of those methods squash the last three commits into a single new commit in the same way. The soft reset just re-points HEAD to the last commit that you do not want to squash. Neither the index nor the working tree are touched by the soft reset, leaving the index in the desired state for your new commit (i.e. it already has all the changes from the commits that you are about to “throw away”).

I recommend avoiding git reset when possible -- especially for Git-novices. Unless you really need to automate a process based on a number of commits, there is a less exotic way...

  1. Put the to-be-squashed commits on a working branch (if they aren't already) -- use gitk for this
  2. Check out the target branch (e.g. 'master')
  3. git merge --squash (working branch name)
  4. git commit

The commit message will be prepopulated based on the squash.

Thanks to this handy blog post I found that you can use this command to squash the last 3 commits:

git rebase -i HEAD~3

This is handy as it works even when you are on a local branch with no tracking information/remote repo.

The command will open the interactive rebase editor which then allows you to reorder, squash, reword, etc as per normal.


Using the interactive rebase editor:

The interactive rebase editor shows the last three commits. This constraint was determined by HEAD~3 when running the command git rebase -i HEAD~3.

The most recent commit, HEAD, is displayed first on line 1. The lines starting with a # are comments/documentation.

The documentation displayed is pretty clear. On any given line you can change the command from pick to a command of your choice.

I prefer to use the command fixup as this "squashes" the commit's changes into the commit on the line above and discards the commit's message.

As the commit on line 1 is HEAD, in most cases you would leave this as pick. You cannot use squash or fixup as there is no other commit to squash the commit into.

You may also change the order of the commits. This allows you to squash or fixup commits that are not adjacent chronologically.


A practical everyday example

I've recently committed a new feature. Since then, I have committed two bug fixes. But now I have discovered a bug (or maybe just a spelling error) in the new feature I committed. How annoying! I don't want a new commit polluting my commit history!

The first thing I do is fix the mistake and make a new commit with the comment squash this into my new feature!.

I then run git log or gitk and get the commit SHA of the new feature (in this case 1ff9460).

Next, I bring up the interactive rebase editor with git rebase -i 1ff9460~. The ~ after the commit SHA tells the editor to include that commit in the editor.

Next, I move the commit containing the fix (fe7f1e0) to underneath the feature commit, and change pick to fixup.

When closing the editor, the fix will get squashed into the feature commit and my commit history will look nice and clean!

This works well when all the commits are local, but if you try to change any commits already pushed to the remote you can really cause problems for other devs that have checked out the same branch!

In the branch you would like to combine the commits on, run:

git rebase -i HEAD~(n number of commits back to review)

example:

git rebase -i HEAD~2

This will open the text editor and you must switch the 'pick' in front of each commit with 'squash' if you would like these commits to be merged together. From documentation:

p, pick = use commit

s, squash = use commit, but meld into previous commit

For example, if you are looking to merge all the commits into one, the 'pick' is the first commit you made and all future ones (placed below the first) should be set to 'squash'. If using vim, use :x in insert mode to save and exit the editor.

Then to continue the rebase:

git add .

git rebase --continue

For more on this and other ways to rewrite your commit history see this helpful post

Anomies answer is good, but I felt insecure about this so I decided to add a couple of screenshots.

Step 0: git log

See where you are with git log. Most important, find the commit hash of the first commit you don't want to squash. So only the :

Step 1: git rebase

Execute git rebase -i [your hash], in my case:

$ git rebase -i 2d23ea524936e612fae1ac63c95b705db44d937d

Step 2: pick / squash what you want

In my case, I want to squash everything on the commit that was first in time. The ordering is from first to last, so exactly the other way as in git log. In my case, I want:

Step 3: Adjust message(s)

If you have picked only one commit and squashed the rest, you can adjust one commit message:

That's it. Once you save this (:wq), you're done. Have a look at it with git log.

If you are on a remote branch(called feature-branch) cloned from a Golden Repository(golden_repo_name), then here's the technique to squash your commits into one:

  1. Checkout the golden repo

    git checkout golden_repo_name
    
  2. Create a new branch from it(golden repo) as follows

    git checkout -b dev-branch
    
  3. Squash merge with your local branch that you have already

    git merge --squash feature-branch
    
  4. Commit your changes (this will be the only commit that goes in dev-branch)

    git commit -m "My feature complete"
    
  5. Push the branch to your local repository

    git push origin dev-branch
    

To squash the last 10 commits into 1 single commit:

git reset --soft HEAD~10 && git commit -m "squashed commit"

If you also want to update the remote branch with the squashed commit:

git push -f
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What can be really convenient:
Find the commit hash you want to squash on top of, say d43e15.

Now use

git reset d43e15
git commit -am 'new commit name'
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