如何使用git回退部分修改

你的名字 2022-09-17 14:23 232阅读 0赞

很多时候，git新手容易误操作，这个时候，可以用git reset 和git revert命令

reset是指将当前head的内容重置，不会留任何痕迹。

Sets the current head to the specified commit and optionally resets the index and working tree to match.

git reset --hard HEAD~3会将最新的3次提交全部重置，就像没有提交过一样。

根据--soft --mixed --hard，会对working tree和index和HEAD进行重置。

revert是撤销某次提交，但是这次撤销也会作为一次提交进行保存

人总有犯错误的时候，如果发现不小心把私货提交到公共代码库，改如何挽回呢？

例如如下代码库：

$ mkdir git-partial-revert
    $ cd git-partial-revert
    $ echo "hello a" >a.txt
    $ echo "hello b" >b.txt
    $ git init
    Initialized empty Git repository in /home/liang/project/git/git-partial-revert/.git/
    $ git add *.txt
    $ git commit -m "initial version"
    [master (root-commit) b5e1a24] initial version
     2 files changed, 2 insertions(+), 0 deletions(-)
     create mode 100644 a.txt
     create mode 100644 b.txt
    $ git log
    commit b5e1a24fc65202977b903435750dd9fb5e0d04d0
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 13:20:38 2010 +0800
    
     initial version

以下是一次错误的修改。

$ echo "hello a from b" >>a.txt
    $ echo "hello b from a" >>b.txt
    $ git commit -a -m "hello a from b"
    [master df3144e] hello a from b
     2 files changed, 2 insertions(+), 0 deletions(-)
    $ git push origin master
    $ git log
    commit df3144e3168f6ec189ed0b2b57908d8d4e862fe5
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 13:22:51 2010 +0800
    
     hello a from b
    
    commit b5e1a24fc65202977b903435750dd9fb5e0d04d0
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 13:20:38 2010 +0800
    
     initial version

错误在于只应该提交对于`a.txt`的修改，`b.txt`的修改是私货，应该留在本地，以后提交。

第一种方法：纯手工修改。取决于要修改的内容多少，这可能是最简单也可能是最笨的方法。

如果错误发生在最新的commit里面，可以使用`git reset`修改。如下：

$ git reset b5e1a24f -- b.txt
    Unstaged changes after reset:
    M       b.txt
    $ cat b.txt
    hello b
    hello b from a
    $ git log
    commit df3144e3168f6ec189ed0b2b57908d8d4e862fe5
    Author: Liang Wang <lwang1@marvell.com>
    Date:   Fri Jul 30 13:22:51 2010 +0800
    
     hello a from b
    
    commit b5e1a24fc65202977b903435750dd9fb5e0d04d0
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 13:20:38 2010 +0800
    
     initial version
    $ git diff
    diff --git a/b.txt b/b.txt
    index b1bdbca..ab47375 100644
    --- a/b.txt
    +++ b/b.txt
    @@ -1 +1,2 @@
     hello b
    +hello b from a
    $ git status
    # On branch master
    # Changes to be committed:
    #   (use "git reset HEAD <file>..." to unstage)
    #
    #       modified:   b.txt
    #
    # Changed but not updated:
    #   (use "git add <file>..." to update what will be committed)
    #   (use "git checkout -- <file>..." to discard changes in working directory)
    #
    #       modified:   b.txt
    #
    $ git diff --cached
    diff --git a/b.txt b/b.txt
    index ab47375..b1bdbca 100644
    --- a/b.txt
    +++ b/b.txt
    @@ -1,2 +1 @@
     hello b
    -hello b from a
    $ git commit -m "revert change in b"
    [master d49f9f2] revert change in b
     1 files changed, 0 insertions(+), 1 deletions(-)
    $ git push origin master
    $ git status
    # On branch master
    # Changed but not updated:
    #   (use "git add <file>..." to update what will be committed)
    #   (use "git checkout -- <file>..." to discard changes in working directory)
    #
    #       modified:   b.txt
    #
    no changes added to commit (use "git add" and/or "git commit -a")
    $ git diff
    diff --git a/b.txt b/b.txt
    index b1bdbca..ab47375 100644
    --- a/b.txt
    +++ b/b.txt
    @@ -1 +1,2 @@
     hello b
    +hello b from a
    $ git log --stat
    commit d49f9f2531ed9106ea53006bd698bbcdd54698e9
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 13:34:43 2010 +0800
    
     revert change in b
    
     b.txt |    1 -
     1 files changed, 0 insertions(+), 1 deletions(-)
    
    commit df3144e3168f6ec189ed0b2b57908d8d4e862fe5
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 13:22:51 2010 +0800
    
     hello a from b
    
     a.txt |    1 +
     b.txt |    1 +
     2 files changed, 2 insertions(+), 0 deletions(-)
    
    commit b5e1a24fc65202977b903435750dd9fb5e0d04d0
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 13:20:38 2010 +0800
    
     initial version
    
     a.txt |    1 +
     b.txt |    1 +
     2 files changed, 2 insertions(+), 0 deletions(-)

这时b的修改就从公共代码库上拿掉了，但是还保留在本地。

或者也可以使用`git revert`。下面操作的缺点是没有保留对于`b.txt`的修改。如何保留修改留给读者作为习题 ![:-)][-]

$ git revert -n df3144e31
    Finished one revert.
    $ git status
    # On branch master
    # Changes to be committed:
    #   (use "git reset HEAD <file>..." to unstage)
    #
    #       modified:   a.txt
    #       modified:   b.txt
    #
    $ git diff --cached
    diff --git a/a.txt b/a.txt
    index 2c5e468..74614c9 100644
    --- a/a.txt
    +++ b/a.txt
    @@ -1,2 +1 @@
     hello a
    -hello a from b
    diff --git a/b.txt b/b.txt
    index ab47375..b1bdbca 100644
    --- a/b.txt
    +++ b/b.txt
    @@ -1,2 +1 @@
     hello b
    -hello b from a
    $ git reset HEAD a.txt
    Unstaged changes after reset:
    M       a.txt
    $ cat a.txt
    hello a
    $ git checkout -- a.txt
    $ cat a.txt
    hello a
    hello a from b
    $ cat b.txt
    hello b
    $ git commit -m "revert change in b"
    [master 5f6a2e1] revert change in b
     1 files changed, 0 insertions(+), 1 deletions(-)
    $ git log --stat
    commit 5f6a2e16bfd59281d0150e3644aa1485dd6c0078
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 14:17:44 2010 +0800
    
     revert change in b
    
     b.txt |    1 -
     1 files changed, 0 insertions(+), 1 deletions(-)
    
    commit df3144e3168f6ec189ed0b2b57908d8d4e862fe5
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 13:22:51 2010 +0800
    
     hello a from b
    
     a.txt |    1 +
     b.txt |    1 +
     2 files changed, 2 insertions(+), 0 deletions(-)
    
    commit b5e1a24fc65202977b903435750dd9fb5e0d04d0
    Author: Liang Wang <a@b.c>
    Date:   Fri Jul 30 13:20:38 2010 +0800
    
     initial version
    
     a.txt |    1 +
     b.txt |    1 +
     2 files changed, 2 insertions(+), 0 deletions(-)

如果错误的修改已经不是最新的commit，则只能使用`git revert`。

[-]: /images/20220828/7deb29a219d349db8c33ab144b716220.png