人生不如意之事十之八九，合并分支往往也不是一帆风顺的。

准备新的feature1分支，继续我们的新分支开发：

git switch -c 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 switch 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1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：

git-br-feature1
这种情况下，Git无法执行“快速合并”，只能试图把各自的修改合并起来，但这种合并就可能会有冲突，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.

果然冲突了！Git告诉我们，readme.txt文件存在冲突，必须手动解决冲突后再提交。git status也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 …” to mark resolution)

both modified:   readme.txt

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

我们可以直接查看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<<<<<<<，=======，>>>>>>>标记出不同分支的内容，我们修改如下后保存：

Creating a new branch is quick and simple.

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也可以看到分支的合并情况：

$ 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).

工作完成。

小结

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为我们希望的内容，再提交。

用git log --graph命令可以看到分支合并图。