Git速成学习第四课：解决冲突

Git速成学习笔记整理于廖雪峰老师的官网网站：https://www.liaoxuefeng.com/ 

我们继续练习，准备新的feature1分支。

$ git checkout -b feature1
Switched to a new branch 'feature1'

修改readme.txt最后一行，改为：“Creating a new branch is quick AND simple”

在feature1分支上提交：

$ git add readme.txt

$ git commit -m "AND simple"
[feature1 14096d0] AND simple
 1 file changed, 1 insertion(+), 1 deletion(-)

切换到master分支

$ git checkout master
Switched to branch 'master'
Your branch is ahead of 'origin/master' by 1 commit.
  (use "git push" to publish your local commits)

Git还会自动提示我们当前master分支比远程的master分支要超前一个提交。

在master分支上把readme.txt文件的最后一行改为：“Creating a new branch is quick & simple”

提交：

$ git add readme.txt 
$ git commit -m "& simple"
[master 5dc6824] & simple
 1 file changed, 1 insertion(+), 1 deletion(-)

现在，master分支和feature1分支各自都分别有新的提交，变成了这样：

这种情况下，Git无法执行“快速合并”，只能是土把各自的修改合并起来，但是这种合并就有可能会有冲突，我们试试看：

$ git merge feature1
Auto-merging readme.txt
CONFLICT (content): Merge conflict in readme.txt
Automatic merge failed; fix conflicts and then commit the result

Git告诉我们，readme.txt文件存在冲突，必须手动解决冲突后在提交。git status可以告诉我们冲突的文件：

$ git status
On branch master
Your branch is ahead of 'origin/master' by 2 commits.
  (use "git push" to publish your local commits)

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.txt

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

我们可以查看readme.txt的内容：

Git is a distributed version control system.
Git is free software distributed under the GPL.
Git has a mutable index called stage.
Git tracks changes of files.
<<<<<<< HEAD
Creating a new branch is quick & simple.
=======
Creating a new branch is quick AND simple.
>>>>>>> feature1

Git用=======和>>>>>>>标记不同分支的内容，我们修改如下后保存：

“Creating a new branch is quick and simple”然后再提交：

$ git add readme.txt 
$ git commit -m "conflict fixed"
[master cf810e4] conflict fixed

现在master分支和feature1分支变成了下图所示：

 用带参数的git log也可以看到分支合并的情况：

$ git log --graph --pretty=oneline --abbrev-commit
*   cf810e4 (HEAD -> master) conflict fixed
|  
| * 14096d0 (feature1) AND simple
* | 5dc6824 & simple
|/  
* b17d20e branch test
* d46f35e (origin/master) remove test.txt
* b84166e add test.txt
* 519219b git tracks changes
* e43a48b understand how stage works
* 1094adb append GPL
* e475afc add distributed
* eaadf4e wrote a readme file

最后删除feature1分支：

$ git branch -d feature1
Deleted branch feature1 (was 14096d0).

Summary

当Git无法自动合并分支时，就必须首先解决冲突。解决冲突后，再提交，合并完成。

解决冲突就是把Git合并失败的文件手动编辑成我们希望的内容，在提交。

用git log --graph命令可以看到分支合并图