[git] rebase로 커밋을 합쳐보자

다른 브랜치에서 커밋을 가져오는 방법은 크게 2가지가 있습니다.

• git merge
• git rebase

둘의 차이점은?

Merge와 rebase의 큰 차이점은 하나로 합치냐 모두 가져오냐 입니다.

merge로 커밋을 합치면 모든 커밋들이 다 보이는 반면, rebase로 합친 커밋로그는 깔끔하게 하나만 남기도록 할 수 있습니다.

git rebase를 이용해서 커밋을 합쳐보자

1. 커밋 리스트 확인

$ git log
commit a1d131c918d52ed96759d1f181e3cac96aa80031
Author: iseunghan <lsh13288@gmail.com>
Date:   Thu Aug 4 07:38:20 2022 +0000

    Third commit

commit a1d131c918d52ed96759d1f181e3cac96aa80031
Author: iseunghan <lsh13288@gmail.com>
Date:   Thu Aug 4 07:38:20 2022 +0000

    Second commit

commit a1d131c918d52ed96759d1f181e3cac96aa80031
Author: iseunghan <lsh13288@gmail.com>
Date:   Thu Aug 4 07:38:20 2022 +0000

    First commit

3개의 커밋이 있다고 가정합니다.

2. git rebase로 합치기

$ git rebase -i @~3
pick 1cc4c33 First Commit
pick 8973c50 Second Commit # pick -> s
pick a1d131c Third Commit  # pick -> s

# Rebase fcf15ab..91a8b37 onto fcf15ab (4 commands)
#
# Commands:
# p, pick <commit> = use commit
# r, reword <commit> = use commit, but edit the commit message
# e, edit <commit> = use commit, but stop for amending
# s, squash <commit> = use commit, but meld into previous commit
# f, fixup [-C | -c] <commit> = like "squash" but keep only the previous
#                    commit's log message, unless -C is used, in which case
#                    keep only this commit's message; -c is same as -C but
#                    opens the editor
# x, exec <command> = run command (the rest of the line) using shell
# b, break = stop here (continue rebase later with 'git rebase --continue')
# d, drop <commit> = remove commit
# l, label <label> = label current HEAD with a name
# t, reset <label> = reset HEAD to a label
# m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]
# .       create a merge commit using the original merge commit's
# .       message (or the oneline, if no original merge commit was
# .       specified); use -c <commit> to reword the commit message
#
# 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.

-i는 interactive 대화형 모드입니다. @~3(또는 HEAD~3 이렇게 사용해도 됨) 최근 3개의 커밋을 rebase하겠다는 뜻입니다.
최종적으로 남기고 싶은 커밋은 pick으로, 합치고 싶은 커밋은 squash의 약자인 s로 변경해줍니다.

3. 최종 변경된 모습

$ git rebase -i @~3
pick 1cc4c33 First Commit
s 8973c50 Second Commit # pick -> s
s a1d131c Third Commit  # pick -> s

# Rebase fcf15ab..91a8b37 onto fcf15ab (4 commands)
#
# Commands:
# p, pick <commit> = use commit
# r, reword <commit> = use commit, but edit the commit message
# e, edit <commit> = use commit, but stop for amending
# s, squash <commit> = use commit, but meld into previous commit
# f, fixup [-C | -c] <commit> = like "squash" but keep only the previous
#                    commit's log message, unless -C is used, in which case
#                    keep only this commit's message; -c is same as -C but
#                    opens the editor
# x, exec <command> = run command (the rest of the line) using shell
# b, break = stop here (continue rebase later with 'git rebase --continue')
# d, drop <commit> = remove commit
# l, label <label> = label current HEAD with a name
# t, reset <label> = reset HEAD to a label
# m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]
# .       create a merge commit using the original merge commit's
# .       message (or the oneline, if no original merge commit was
# .       specified); use -c <commit> to reword the commit message
#
# 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.

이후 :wq 로 빠져나옵니다.

4. 커밋 정리

# This is a combination of 4 commits.
# This is the 1st commit message:

First commit
# This is the commit message #2:

Second commit
# This is the commit message #3:

Third commit

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# Date:      Thu Aug 4 07:25:11 2022 +0000
#
# interactive rebase in progress; onto fcf15ab
# Last commands done (4 commands done):
#    squash a1d131c Update .gitlab-ci.yml file
#    squash 91a8b37 Update .gitlab-ci.yml file
# No commands remaining.
# You are currently rebasing branch 'deploy' on 'fcf15ab'.
#
# Changes to be committed:
#       new file:   .gitlab-ci.yml
#

Third commit 부분만 남겨두고 나머지 부분은 삭제해줍니다.

5. 최종적인 모습

Third commit

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# Date:      Thu Aug 4 07:25:11 2022 +0000
#
# interactive rebase in progress; onto fcf15ab
# Last commands done (4 commands done):
#    squash a1d131c Update .gitlab-ci.yml file
#    squash 91a8b37 Update .gitlab-ci.yml file
# No commands remaining.
# You are currently rebasing branch 'deploy' on 'fcf15ab'.
#
# Changes to be committed:
#       new file:   .gitlab-ci.yml
#

6. 커밋 확인

$ git log
commit a1d131c918d52ed96759d1f181e3cac96aa80031
Author: iseunghan <lsh13288@gmail.com>
Date:   Thu Aug 4 07:38:20 2022 +0000

    Third commit

이렇게 깔끔하게 커밋을 합쳐보았습니다. 한가지 주의할 점은 이미 저장소에 푸시한 상태일때는 가급적 rebase를 사용하지 않는것이 좋습니다. 왜냐하면 다른 사람이 봤을 때는 동일한 커밋인데 내용은 rebase로 합쳐졌기 때문에 혼란이 올 수 있기 때문입니다. 그렇기에 로컬에서 작업을 하고 저장소에 푸시하기 전에 커밋을 깔끔하게 다듬는 역할로 사용하면 좋을 것 같습니다. 감사합니다.

좀 더 자세한 내용은 아래 FlyingSquirrel님의 medium에서 확인하실 수 있습니다.

REFERENCES

git rebase 하는 방법