在很多时候，随着开发团队的扩容，大家提交代码一段时间过后，就产生很多的合并（merge）节点，对于有代码洁癖的人来说，这个总会觉得很不爽。

master分支混乱的提交历史

那么，merge是如何产生的呢？下面我挑一个常见的冲突的场景，示例一下：

用merge来解决冲突

我们来在master分支模拟一次merge的情况，针对README.md，首先A用户编写了首行代码，并提交到了git服务器上内容如下：

# A用户编写首行代码

同时，B用户在本地编写了首行代码，内容如下：

# B用户编写首行代码

B用户只是在本地电脑上进行了git commit，如下：

$ git commit -am "B用户编写首行代码"
[master c8bfe4f] B用户编写首行代码
 1 file changed, 1 insertion(+), 1 deletion(-)

接下来，B用户使用git pull命令将git服务器代码下载并合并到本地，可以看到产生了冲突：

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git pull
remote: Counting objects: 3, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 0), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
From gitee.com:yyxz/test
   45bc85e..fc2c29a  master     -> origin/master
Auto-merging README.md
CONFLICT (content): Merge conflict in README.md
Automatic merge failed; fix conflicts and then commit the result.

接下来，B用户，修改有冲突的README.md文件，解决冲突，如下：

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master|MERGING)
$ git status
On branch master
Your branch and 'origin/master' have diverged,
and have 1 and 1 different commits each, respectively.
  (use "git pull" to merge the remote branch into yours)
You have unmerged paths.
  (fix conflicts and run "git commit")
  (use "git merge --abort" to abort the merge)

Unmerged paths:
  (use "git add <file>..." to mark resolution)

        both modified:   README.md

no changes added to commit (use "git add" and/or "git commit -a")

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master|MERGING)
$ git add README.md

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master|MERGING)
$ git commit -m "合并A和B用户编写的首行代码"
[master 5aa451d] 合并A和B用户编写的首行代码

修改后的README.md文件内容如下：

# 合并A和B用户编写的首行代码

现在B将代码提交到git服务器上，可以看到有两个commit（一个是B对首行代码的提交：c8bfe4f，一个是B刚才的merge动作），如下：

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git status
On branch master
Your branch is ahead of 'origin/master' by 2 commits.
  (use "git push" to publish your local commits)
nothing to commit, working tree clean

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git push
Counting objects: 6, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (6/6), 695 bytes | 0 bytes/s, done.
Total 6 (delta 0), reused 0 (delta 0)
To gitee.com:yyxz/test.git
   fc2c29a..5aa451d  master -> master

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git log --oneline --graph
*   5aa451d (HEAD -> master, origin/master, origin/HEAD) 合并A和B用户编写的首行代码
|\
| * fc2c29a A用户编写首行代码
* | c8bfe4f B用户编写首行代码
|/
* 45bc85e 初始状态

可以看到，提交历史产生了分叉，接下来我们看看如何使用git rebase消除分叉：

git rebase消除分叉

A再次修改首行代码，并提交至git服务器，README.md内容如下：

A再次修改首行代码

B再次在本地修改首行代码，并提交至本地，README.md内容如下：

B再次修改首行代码

commit如下：

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git commit -am "B再次修改首行代码"
[master 21a6c2a] B再次修改首行代码
 1 file changed, 1 insertion(+), 1 deletion(-)

接下来，使用git pull --rabase，可以看到冲突，并且进入了rebase状态：

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git pull --rebase
remote: Counting objects: 3, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 0), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
From gitee.com:yyxz/test
   5aa451d..ccbb4ff  master     -> origin/master
First, rewinding head to replay your work on top of it...
Applying: B再次修改首行代码
error: Failed to merge in the changes.
Using index info to reconstruct a base tree...
M       README.md
Falling back to patching base and 3-way merge...
Auto-merging README.md
CONFLICT (content): Merge conflict in README.md
Patch failed at 0001 B再次修改首行代码
The copy of the patch that failed is found in: .git/rebase-apply/patch

When you have resolved this problem, run "git rebase --continue".
If you prefer to skip this patch, run "git rebase --skip" instead.
To check out the original branch and stop rebasing, run "git rebase --abort".


bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master|REBASE 1/1)
$

此时，B在本地打开README.md文件，可以看到冲突内容如下：

<<<<<<< HEAD
A再次修改首行代码
=======
B再次修改首行代码
>>>>>>> B再次修改首行代码

解决冲突：修改README.md文件，内容如下：

再次合并A和B修改的首行代码

使用git add README.md标注冲突已解决：

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master|REBASE 1/1)
$ git add README.md

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master|REBASE 1/1)
$ git rebase --continue
Applying: B再次修改首行代码

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git log --oneline --graph
* 1e4c421 (HEAD -> master) B再次修改首行代码
* ccbb4ff (origin/master, origin/HEAD) A再次修改首行代码
*   5aa451d 合并A和B用户编写的首行代码
|\
| * fc2c29a A用户编写首行代码
* | c8bfe4f B用户编写首行代码
|/
* 45bc85e 初始状态

可以看到B用户第二次修改是在A修改之后，但是B的提交commit编号21a6c2a被新的编号1e4c421所取代，commit的内容不变。

这时我们看到HEAD -> master，origin/master, origin/HEAD不一致。是因为B用户在本地的修改还未提交至git服务器，通过git status也可以看出来，有1 commit未提交至git服务器：

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git status
On branch master
Your branch is ahead of 'origin/master' by 1 commit.
  (use "git push" to publish your local commits)
nothing to commit, working tree clean

提交后，就OK了。如下：

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git push
Counting objects: 3, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 355 bytes | 0 bytes/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To gitee.com:yyxz/test.git
   ccbb4ff..1e4c421  master -> master

bianxh@DESKTOP-BIANXH MINGW64 /d/Workspaces/gitee/test (master)
$ git log --oneline --graph
* 1e4c421 (HEAD -> master, origin/master, origin/HEAD) B再次修改首行代码
* ccbb4ff A再次修改首行代码
*   5aa451d 合并A和B用户编写的首行代码
|\
| * fc2c29a A用户编写首行代码
* | c8bfe4f B用户编写首行代码
|/
* 45bc85e 初始状态

现在我们登录到服务器看下最新的内容，如下：

使用rebase解决冲突后的README.md文件内容

可以通过项目网络图直观地看到，如下：

项目网络图