08 分支管理 —— 多人协做

08 分支管理 —— 多人协做

多人协做

本节内容：

查看远程库信息，使用git remote -v；
本地新建的分支若是不推送到远程，对其余人就是不可见的；
从本地推送分支，使用git push origin branch-name，若是推送失败，先用git pull抓取远程的新提交；
在本地建立和远程分支对应的分支，使用git checkout -b branch-name origin/branch-name，本地和远程分支的名称最好一致；
创建本地分支和远程分支的关联，使用git branch --set-upstream branch-name origin/branch-name；
从远程抓取分支，使用git pull，若是有冲突，要先处理冲突。

当你从远程仓库克隆时，实际上Git自动把本地的master分支和远程的master分支对应起来了，而且，远程仓库的默认名称是origin。

要查看远程库的信息，用git remote：

lwenhaodeMacBook-Pro:TestGit lwenhao$ git remote
origin
lwenhaodeMacBook-Pro:TestGit lwenhao$

或者用git remote -v显示更详细的信息：

lwenhaodeMacBook-Pro:TestGit lwenhao$ git remote -v
origin	https://github.com/liuwenhaoCN/TestGit.git (fetch)
origin	https://github.com/liuwenhaoCN/TestGit.git (push)
lwenhaodeMacBook-Pro:TestGit lwenhao$

上面显示了能够抓取和推送的origin的地址。若是没有推送权限，就看不到push的地址。

推送分支

推送分支，就是把该分支上的全部本地提交推送到远程库。推送时，要指定本地分支，这样Git就会把该分支推送到远程库对应的远程分支上：

git push origin master

若是要推送其余分支，好比dev，就改为：

lwenhaodeMacBook-Pro:TestGit lwenhao$ git push origin dev
Total 0 (delta 0), reused 0 (delta 0)
remote: This repository moved. Please use the new location:
remote:   https://github.com/lwenhaoCN/TestGit.git
remote: 
remote: Create a pull request for 'dev' on GitHub by visiting:
remote:      https://github.com/lwenhaoCN/TestGit/pull/new/dev
remote: 
To https://github.com/liuwenhaoCN/TestGit.git
 * [new branch]      dev -> dev
lwenhaodeMacBook-Pro:TestGit lwenhao$

可是，并非必定要把本地分支往远程推送，那么，哪些分支须要推送，哪些不须要呢？

• master分支是主分支，所以要时刻与远程同步；
• dev分支是开发分支，团队全部成员都须要在上面工做，因此也须要与远程同步；
• bug分支只用于在本地修复bug，就不必推到远程了，除非老板要看看你每周到底修复了几个bug；
• feature分支是否推到远程，取决于你是否和你的小伙伴合做在上面开发。

总之，就是在Git中，分支彻底能够在本地本身藏着玩，是否推送，视你的心情而定！

抓取分支

多人协做时，你们都会往master和dev分支上推送各自的修改。

如今，模拟一个你的小伙伴，能够在另外一台电脑（注意要把SSH Key添加到GitHub）或者同一台电脑的另外一个目录下克隆：新建Test文件夹，把TestGit克隆到该文件夹（这个文件夹模拟你的小伙伴）。

lwenhaodeMacBook-Pro:Test lwenhao$ git clone 'https://github.com/lwenhaoCN/TestGit.git'
Cloning into 'TestGit'...
remote: Enumerating objects: 23, done.
remote: Counting objects: 100% (23/23), done.
remote: Compressing objects: 100% (10/10), done.
remote: Total 23 (delta 3), reused 20 (delta 3), pack-reused 0
Unpacking objects: 100% (23/23), done.
lwenhaodeMacBook-Pro:Test lwenhao$

当你的小伙伴从远程库clone时，默认状况下，你的小伙伴只能看到本地的master分支。使用git branch命令查看：

lwenhaodeMacBook-Pro:Test lwenhao$ cd TestGit/
lwenhaodeMacBook-Pro:TestGit lwenhao$ git branch
* master
lwenhaodeMacBook-Pro:TestGit lwenhao$

如今，你的小伙伴要在dev分支上开发，就必须建立远程origin的dev分支到本地，因而他用这个命令建立本地dev分支：

lwenhaodeMacBook-Pro:TestGit lwenhao$ git checkout -b dev origin/dev
Branch 'dev' set up to track remote branch 'dev' from 'origin'.
Switched to a new branch 'dev'
lwenhaodeMacBook-Pro:TestGit lwenhao$

而且你的小伙伴修改README.md文件内容：

lwenhaodeMacBook-Pro:TestGit lwenhao$ cat README.md 
# TestGit

建立一个"dev"分支，我来操做。

学习分支管理策略。

dev、dev、dev

lwenhaodeMacBook-Pro:TestGit lwenhao$

他就能够在dev上继续修改，而后时不时地把dev分支push到远程：

lwenhaodeMacBook-Pro:TestGit lwenhao$ git add README.md 
lwenhaodeMacBook-Pro:TestGit lwenhao$ git commit -m "add dev"
[dev 0f59233] add dev
 1 file changed, 2 insertions(+)
lwenhaodeMacBook-Pro:TestGit lwenhao$ git push origin dev
Counting objects: 3, done.
Delta compression using up to 12 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 267 bytes | 267.00 KiB/s, done.
Total 3 (delta 1), reused 0 (delta 0)
remote: Resolving deltas: 100% (1/1), completed with 1 local object.
To https://github.com/lwenhaoCN/TestGit.git
   8faa495..0f59233  dev -> dev
lwenhaodeMacBook-Pro:TestGit lwenhao$

你的小伙伴已经向origin/dev分支推送了他的提交，而碰巧你也对一样的文件做了修改，并试图推送：

如今返回到你原来的TestGit中，而且修改README.md内容：

lwenhaodeMacBook-Pro:TestGit lwenhao$ cat README.md 
# TestGit

建立一个"dev"分支，我来操做。

学习分支管理策略。

我本身写的。

lwenhaodeMacBook-Pro:TestGit lwenhao$

你本身提交dev分支下的README.md

lwenhaodeMacBook-Pro:TestGit lwenhao$ git add README.md 
lwenhaodeMacBook-Pro:TestGit lwenhao$ git commit -m "add my"
[dev 29bc6cb] add my
 1 file changed, 2 insertions(+)
lwenhaodeMacBook-Pro:TestGit lwenhao$ git push origin dev
To https://github.com/liuwenhaoCN/TestGit.git
 ! [rejected]        dev -> dev (fetch first)
error: failed to push some refs to 'https://github.com/liuwenhaoCN/TestGit.git'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.
lwenhaodeMacBook-Pro:TestGit lwenhao$

推送失败，由于你的小伙伴的最新提交和你试图推送的提交有冲突，解决办法也很简单，Git已经提示咱们，先用git pull把最新的提交从origin/dev抓下来，而后在本地合并，解决冲突，再推送：

lwenhaodeMacBook-Pro:TestGit lwenhao$ git pull
remote: Enumerating objects: 5, done.
remote: Counting objects: 100% (5/5), done.
remote: Compressing objects: 100% (1/1), done.
remote: Total 3 (delta 1), reused 3 (delta 1), pack-reused 0
Unpacking objects: 100% (3/3), done.
From https://github.com/liuwenhaoCN/TestGit
   8faa495..0f59233  dev        -> origin/dev
There is no tracking information for the current branch.
Please specify which branch you want to merge with.
See git-pull(1) for details.

    git pull <remote> <branch>

If you wish to set tracking information for this branch you can do so with:

    git branch --set-upstream-to=origin/<branch> dev

lwenhaodeMacBook-Pro:TestGit lwenhao$

git pull也失败了，缘由是没有指定本地dev分支与远程origin/dev分支的连接，根据提示，设置dev和origin/dev的连接：

lwenhaodeMacBook-Pro:TestGit lwenhao$ git branch --set-upstream-to=origin/dev dev
Branch 'dev' set up to track remote branch 'dev' from 'origin'.
lwenhaodeMacBook-Pro:TestGit lwenhao$

在使用git pull：

lwenhaodeMacBook-Pro:TestGit lwenhao$ git pull
Auto-merging README.md
CONFLICT (content): Merge conflict in README.md
Automatic merge failed; fix conflicts and then commit the result.
lwenhaodeMacBook-Pro:TestGit lwenhao$

这回git pull成功，可是合并有冲突，须要手动解决，解决的方法和04 分支管理 —— 解决冲突的彻底同样。解决后，提交，再push：

lwenhaodeMacBook-Pro:TestGit lwenhao$ git add README.md 
lwenhaodeMacBook-Pro:TestGit lwenhao$ git commit -m "fix README.md conflict"
[dev cd4d07d] fix README.md conflict
lwenhaodeMacBook-Pro:TestGit lwenhao$ git push origin dev
Counting objects: 6, done.
Delta compression using up to 12 threads.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (6/6), 524 bytes | 524.00 KiB/s, done.
Total 6 (delta 2), reused 0 (delta 0)
remote: Resolving deltas: 100% (2/2), completed with 1 local object.
remote: This repository moved. Please use the new location:
remote:   https://github.com/lwenhaoCN/TestGit.git
To https://github.com/liuwenhaoCN/TestGit.git
   0f59233..cd4d07d  dev -> dev
lwenhaodeMacBook-Pro:TestGit lwenhao$

所以，多人协做的工做模式一般是这样：

1. 首先，能够试图用git push origin <branch-name>推送本身的修改；
2. 若是推送失败，则由于远程分支比你的本地更新，须要先用git pull试图合并；
3. 若是合并有冲突，则解决冲突，并在本地提交；
4. 没有冲突或者解决掉冲突后，再用git push origin <branch-name>推送就能成功！

若是git pull提示no tracking information，则说明本地分支和远程分支的连接关系没有建立，用命令git branch --set-upstream-to <branch-name> origin/<branch-name>。