快速处理 Git 冲突
涛叔我一直是在终端下使用 git 的。如果合并分支或者执行 rebase 遇到冲突，处理起来比较麻烦。今天 rebase 开发分支的时候又遇到了一堆冲突，于是就花了点时间研究如何快速处理 git 冲突。方法很简单，就是将 conflictstyle 配置改成 diff3。下面为大家细细分解。
我准备了一个演示项目，大家可以去 https://github.com/taoso/git-conflictstyle-demo 克隆。
git 的默认 conflictstyle 是 merge，遇到冲突后（在演示项目执行 git merge feature_branch）会显示如下标记：
<<<<<<< HEAD
Alice asked her parents if she could
borrow their car. They said ok but told
=======
Alice asked her father if she could
borrow his motorbike. He said ok but told
>>>>>>> feature_branch
her she had to be back by 11pm.这其中<<<<<<< HEAD与=======之间的部分表示当前所在分支（也就是HEAD）的内容，而=======与>>>>>>> feature_branch之间的部分则是 feature_branch 分支的内容。看到这个冲突就头大，因为我们无法确定要留哪一行删哪一行。
如果我们执行git config --global merge.conflictstyle diff3将conflictstyle设成 diff3，则结果会变成
<<<<<<< HEAD
Alice asked her parents if she could
borrow their car. They said ok but told
||||||| merged common ancestors
Alice asked her father if she could
borrow his car. He said ok but told
=======
Alice asked her father if she could
borrow his motorbike. He said ok but told
>>>>>>> feature_branch
her she had to be back by 11pm.大家注意多出来的||||||| merged common ancestors到=======之间的部分。git 在合并分支的时候用的是三路合并(3-way merge)。三路合并的关键就是找到两个分支的最新公共提交版本。在这个例子中，公共提交版本的内容就保存到 ||||||| merged common ancestors和=======之间。
很显然，master 分支将Alice asked her father if she could改成了Alice asked her parents if she could，也就是 Alice 现在要向她的父母借车；而 feature_branch 分支则将 borrow his car...改成了borrow his motorbike...，也就是不借车了，要借摩托。两者合并，最终结果应该是：
Alice asked her parents if she could
borrow their motorbike. They said ok but told
her she had to be back by 11pm.我还找了一个例子。
cauliflower
<<<<<<< HEAD
peas
potatoes
=======
>>>>>>> topic
tomatoes单看这种merge风格的冲突会很困惑，为什么 peas 会和空行冲突呢？如果开启了三路冲突展示，你会看到
cauliflower
<<<<<<< HEAD
peas
potatoes
||||||| merged common ancestors
peas
=======
>>>>>>> topic
tomatoes这下就明了了，原来是 topic 分支删掉了 peas 一行，而当前分支又在 peas 下加了 potatoes 一行。所以正确的处理结果应该是只保留 potatoes。如果不开启 diff3选项，我们是很难正确处理这类冲突的。
好了，今天就说到这里。三路合并冲突你理解了吗？欢迎留言讨论。