08 分支管理 —— 多人協做

08 分支管理 —— 多人協做

多人協做

本節內容：

查看遠程庫信息，使用git remote -v；
本地新建的分支若是不推送到遠程，對其餘人就是不可見的；
從本地推送分支，使用git push origin branch-name，若是推送失敗，先用git pull抓取遠程的新提交；
在本地建立和遠程分支對應的分支，使用git checkout -b branch-name origin/branch-name，本地和遠程分支的名稱最好一致；
創建本地分支和遠程分支的關聯，使用git branch --set-upstream branch-name origin/branch-name；
從遠程抓取分支，使用git pull，若是有衝突，要先處理衝突。

當你從遠程倉庫克隆時，實際上Git自動把本地的master分支和遠程的master分支對應起來了，而且，遠程倉庫的默認名稱是origin。

要查看遠程庫的信息，用git remote：

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

或者用git remote -v顯示更詳細的信息：

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$

上面顯示了能夠抓取和推送的origin的地址。若是沒有推送權限，就看不到push的地址。

推送分支

推送分支，就是把該分支上的全部本地提交推送到遠程庫。推送時，要指定本地分支，這樣Git就會把該分支推送到遠程庫對應的遠程分支上：

git push origin master

若是要推送其餘分支，好比dev，就改爲：

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，並非必定要把本地分支往遠程推送，那麼，哪些分支須要推送，哪些不須要呢？

• master分支是主分支，所以要時刻與遠程同步；
• dev分支是開發分支，團隊全部成員都須要在上面工做，因此也須要與遠程同步；
• bug分支只用於在本地修復bug，就不必推到遠程了，除非老闆要看看你每週到底修復了幾個bug；
• feature分支是否推到遠程，取決於你是否和你的小夥伴合做在上面開發。

總之，就是在Git中，分支徹底能夠在本地本身藏着玩，是否推送，視你的心情而定！

抓取分支

多人協做時，你們都會往master和dev分支上推送各自的修改。

如今，模擬一個你的小夥伴，能夠在另外一臺電腦（注意要把SSH Key添加到GitHub）或者同一臺電腦的另外一個目錄下克隆：新建Test文件夾，把TestGit克隆到該文件夾（這個文件夾模擬你的小夥伴）。

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$

當你的小夥伴從遠程庫clone時，默認狀況下，你的小夥伴只能看到本地的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，你的小夥伴要在dev分支上開發，就必須建立遠程origin的dev分支到本地，因而他用這個命令建立本地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$

而且你的小夥伴修改README.md文件內容：

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

建立一個"dev"分支，我來操做。

學習分支管理策略。

dev、dev、dev

lwenhaodeMacBook-Pro:TestGit lwenhao$

他就能夠在dev上繼續修改，而後時不時地把dev分支push到遠程：

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$

你的小夥伴已經向origin/dev分支推送了他的提交，而碰巧你也對一樣的文件做了修改，並試圖推送：

如今返回到你原來的TestGit中，而且修改README.md內容：

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

建立一個"dev"分支，我來操做。

學習分支管理策略。

我本身寫的。

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$

推送失敗，由於你的小夥伴的最新提交和你試圖推送的提交有衝突，解決辦法也很簡單，Git已經提示咱們，先用git pull把最新的提交從origin/dev抓下來，而後在本地合併，解決衝突，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也失敗了，緣由是沒有指定本地dev分支與遠程origin/dev分支的連接，根據提示，設置dev和origin/dev的連接：

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$

這回git pull成功，可是合併有衝突，須要手動解決，解決的方法和04 分支管理 —— 解決衝突的徹底同樣。解決後，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，多人協做的工做模式一般是這樣：

1. 首先，能夠試圖用git push origin <branch-name>推送本身的修改；
2. 若是推送失敗，則由於遠程分支比你的本地更新，須要先用git pull試圖合併；
3. 若是合併有衝突，則解決衝突，並在本地提交；
4. 沒有衝突或者解決掉衝突後，再用git push origin <branch-name>推送就能成功！

若是git pull提示no tracking information，則說明本地分支和遠程分支的連接關係沒有建立，用命令git branch --set-upstream-to <branch-name> origin/<branch-name>。