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liuhui · 更新于 2018-11-28 11:00:43

找回丢失的对象

在玩 Git 的过程中,常有失误的时候,有时把需要的东东给删了。不过没有关系,Git 给了我们一层安全网,让们能有机会把失去的东西给找回来。

准备

我们先创建一个用以实验的仓库,在里面创建了若干个提交和分支。 BTW:你可以直接把下面的命令复制到 shell 里执行。

mkdir recovery;cd recovery
git init
touch file
git add file
git commit -m "First commit"
echo "Hello World" > file
git add .
git commit -m "Greetings"
git branch cool_branch 
git checkout cool_branch
echo "What up world?" > cool_file
git add .
git commit -m "Now that was cool"
git checkout master
echo "What does that mean?" >> file

恢复已删除分支提交

现在 repo 里有两个 branch

$ git branch
cool_branch
* master

存储当前仓库未提交的改动

$ git stash save "temp save"
Saved working directory and index state On master: temp save
HEAD is now at e3c9b6b Greetings

删除一个分支

$ git branch -D cool_branch
Deleted branch cool_branch (was 2e43cd5).

$ git branch
 * master

git fsck --lost-found命令找出刚才删除的分支里面的提交对象。

$git fsck --lost-found
  dangling commit 2e43cd56ee4fb08664cd843cd32836b54fbf594a

git show命令查看一个找到的对象的内容,看是否为我们所找的。

git show 2e43cd56ee4fb08664cd843cd32836b54fbf594a

  commit 2e43cd56ee4fb08664cd843cd32836b54fbf594a
  Author: liuhui <liuhui998[#]gmail.com>
  Date:   Sat Oct 23 12:53:50 2010 +0800

  Now that was cool

  diff --git a/cool_file b/cool_file
  new file mode 100644
  index 0000000..79c2b89
  --- /dev/null
  +++ b/cool_file
  @@ -0,0 +1 @@
  +What up world?

这个提交对象确实是我们在前面删除的分支的内容;下面我们就要考虑一下要如何来恢复它了。

使用 git rebase 进行恢复

  $git rebase 2e43cd56ee4fb08664cd843cd32836b54fbf594a
  First, rewinding head to replay your work on top of it...
  Fast-forwarded master to 2e43cd56ee4fb08664cd843cd32836b54fbf594a

现在我们用git log命令看一下,看看它有没有恢复:

  $ git log

  commit 2e43cd56ee4fb08664cd843cd32836b54fbf594a
  Author: liuhui <liuhui998[#]gmail.com>
  Date:   Sat Oct 23 12:53:50 2010 +0800

  Now that was cool

  commit e3c9b6b967e6e8c762b500202b146f514af2cb05
  Author: liuhui <liuhui998[#]gmail.com>
  Date:   Sat Oct 23 12:53:50 2010 +0800

  Greetings

  commit 5e90516a4a369be01b54323eb8b2660545051764
  Author: liuhui <liuhui998[#]gmail.com>
  Date:   Sat Oct 23 12:53:50 2010 +0800

  First commit

提交是找回来,但是分支没有办法找回来:

  liuhui@liuhui:~/work/test/git/recovery$ git branch
  * master

使用 git merge 进行恢复

我们把刚才的恢复的提交删除

  $ git reset --hard HEAD^
  HEAD is now at e3c9b6b Greetings

再把刚删的提交给找回来:

  git fsck --lost-found
  dangling commit 2e43cd56ee4fb08664cd843cd32836b54fbf594a

不过这回我们用是合并命令进行恢复:

  $ git merge 2e43cd56ee4fb08664cd843cd32836b54fbf594a
  Updating e3c9b6b..2e43cd5
  Fast-forward
  cool_file |    1 +
  1 files changed, 1 insertions(+), 0 deletions(-)
  create mode 100644 cool_file

git stash 的恢复

前面我们用 git stash 把没有提交的内容进行了存储,如果这个存储不小心删了怎么办呢?

当前 repo 里有的存储:

$ git stash list
stash@{0}: On master: temp save

把它们清空:

$git stash clear
liuhui@liuhui:~/work/test/git/recovery$ git stash list

再用git fsck --lost-found找回来:

$git fsck --lost-found
dangling commit 674c0618ca7d0c251902f0953987ff71860cb067

git show看一下回来的内容对不对:

$git show 674c0618ca7d0c251902f0953987ff71860cb067

commit 674c0618ca7d0c251902f0953987ff71860cb067
Merge: e3c9b6b 2b2b41e
Author: liuhui <liuhui998[#]gmail.com>
Date:   Sat Oct 23 13:44:49 2010 +0800

    On master: temp save

diff --cc file
index 557db03,557db03..f2a8bf3
--- a/file
+++ b/file
@@@ -1,1 -1,1 +1,2 @@@
  Hello World
  ++What does that mean?

看起来没有问题,好的,那么我就把它恢复了吧:

$ git merge 674c0618ca7d0c251902f0953987ff71860cb067
Merge made by recursive.
 file |    1 +
  1 files changed, 1 insertions(+), 0 deletions(-)

备注

这篇文章主要内容来自这里:The illustrated guide to recovering lost commits with Git,我做了一些整理的工作。

如果对于文中的一些命令不熟,可以参考 Git Community Book 中文版

其实这里最重要的一个命令就是:git fsck --lost-found,因为 Git 中把 commit 删了后,并不是真正的删除,而是变成了悬空对象(dangling commit)。我们只要把把这悬空对象(dangling commit)找出来,用 git rebase也好,用git merge也行就能把它们给恢复。

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