GIT 分支管理：多人协作

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，并且，远程仓库的默认名称是origin。

要查看远程库的信息，用git remote：

$ git remote
origin

或者，用git remote -v显示更详细的信息：

$ git remote -v
origin  https://github.com/wangmingshun/studygit.git (fetch)
origin  https://github.com/wangmingshun/studygit.git (push)

上面显示了可以抓取和推送的origin的地址。如果没有推送权限，就看不到push的地址。

推送分支

推送分支，就是把该分支上的所有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
Username for 'https://github.com': wangmingshun
Counting objects: 27, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (27/27), done.
Writing objects: 100% (27/27), 2.39 KiB | 0 bytes/s, done.
Total 27 (delta 10), reused 0 (delta 0)
To https://github.com/wangmingshun/studygit.git
90bc1f7..9565f59 master -> master

 

如果要推送其他分支，比如dev，就改成：

$ git push origin dev
Username for 'https://github.com': wangmingshun
Counting objects: 3, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 297 bytes | 0 bytes/s, done.
Total 3 (delta 1), reused 0 (delta 0)
To https://github.com/wangmingshun/studygit.git
* [new branch] dev -> dev

但是，并不是一定要把本地分支往远程推送，那么，哪些分支需要推送，哪些不需要呢？

• master分支是主分支，因此要时刻与远程同步；

• dev分支是开发分支，团队所有成员都需要在上面工作，所以也需要与远程同步；

• bug分支只用于在本地修复bug，就没必要推到远程了，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作在上面开发。

总之，就是在Git中，分支完全可以在本地自己藏着玩，是否推送，视你的心情而定！

抓取分支

多人协作时，大家都会往master和dev分支上推送各自的修改。

现在，模拟一个你的小伙伴，可以在另一台电脑（注意要把SSH Key添加到GitHub）或者同一台电脑的另一个目录下克隆：

$ git clone git@github.com:wangmingshun/studygit.git
Cloning into 'studygit'...
Warning: Permanently added the RSA host key for IP address '192.30.252.131' to the list of known hosts.
remote: Counting objects: 40, done.
remote: Compressing objects: 100% (24/24), done.
remote: Total 40 (delta 6), reused 40 (delta 6), pack-reused 0
Receiving objects: 100% (40/40), done.
Resolving deltas: 100% (6/6), done.
Checking connectivity... done.

当你的小伙伴从远程库clone时，默认情况下，你的小伙伴只能看到本地的master分支。不信可以用git branch命令看看：

$ git branch
* master

首先先pull或者fetch下，否则报错

$ git pull
remote: Counting objects: 3, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 1), reused 3 (delta 1), pack-reused 0
Unpacking objects: 100% (3/3), done.
From github.com:wangmingshun/studygit
 * [new branch]      dev        -> origin/dev
Updating 90bc1f7..9565f59
Fast-forward
 readme.txt | 6 ++++++
 1 file changed, 6 insertions(+)

 

现在，你的小伙伴要在dev分支上开发，就必须创建远程origin的dev分支到本地，于是他用这个命令创建本地dev分支：

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

 

现在，他就可以在dev上继续修改，然后，时不时地把dev分支push到远程：

$ git add .
$ git commit -m "test remote dev"
[dev 36cc09a] test remote dev
 2 files changed, 6 insertions(+), 2 deletions(-)
$ git push origin dev
Warning: Permanently added the RSA host key for IP address '192.30.252.129' to the list of known hosts.
Counting objects: 4, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (4/4), 336 bytes | 0 bytes/s, done.
Total 4 (delta 1), reused 0 (delta 0)
To git@github.com:wangmingshun/studygit.git
   b7c506b..36cc09a  dev -> dev

 

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

$ git add .
$ git commit -m "dddd"
[dev d824e44] dddd
 1 file changed, 2 insertions(+), 1 deletion(-)
$ git push origin dev
Username for 'https://github.com': wangmingshun
To https://github.com/wangmingshun/studygit.git
 ! [rejected]        dev -> dev (fetch first)
error: failed to push some refs to 'https://github.com/wangmingshun/studygit.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.

 

推送失败，因为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已经提示我们，先用git pull把最新的提交从origin/dev抓下来，然后，在本地合并，解决冲突，再推送：

$ git pull
remote: Counting objects: 4, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 4 (delta 1), reused 4 (delta 1), pack-reused 0
Unpacking objects: 100% (4/4), done.
From https://github.com/wangmingshun/studygit
   b7c506b..36cc09a  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

git pull也失败了，原因是没有指定本地dev分支与远程origin/dev分支的链接，根据提示，设置dev和origin/dev的链接：

$ git branch --set-upstream-to=origin/dev
Branch dev set up to track remote branch dev from origin.

 

再pull:

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

这回git pull成功，但是合并有冲突，需要手动解决，解决的方法和分支管理中的解决冲突完全一样。解决后，提交，再push：

$ git add .
$ git commit -m "多人远程仓库提交冲突解决"
[dev 8737740] 多人远程仓库提交冲突解决
$ git push origin dev
Username for 'https://github.com': wangmingshun
Counting objects: 6, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (6/6), done.
Writing objects: 100% (6/6), 632 bytes | 0 bytes/s, done.
Total 6 (delta 2), reused 0 (delta 0)
To https://github.com/wangmingshun/studygit.git
   36cc09a..8737740  dev -> dev

因此，多人协作的工作模式通常是这样：

1. 首先，可以试图用git push origin branch-name推送自己的修改；

2. 如果推送失败，则因为远程分支比你的本地更新，需要先用git pull试图合并；

3. 如果合并有冲突，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！

如果git pull提示“no tracking information”，则说明本地分支和远程分支的链接关系没有创建，用命令git branch --set-upstream branch-name origin/branch-name。

这就是多人协作的工作模式，一旦熟悉了，就非常简单。

小结

• 查看远程库信息，使用git remote -v；

• 本地新建的分支如果不推送到远程，对其他人就是不可见的；

• 从本地推送分支，使用git push origin branch-name，如果推送失败，先用git pull抓取远程的新提交；

• 在本地创建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；

• 建立本地分支和远程分支的关联，使用git branch --set-upstream-to=origin/branch-name

• 从远程抓取分支，使用git pull，如果有冲突，要先处理冲突。