1. 假定原作者的名稱叫g(shù)ittest, 我叫uniquejava.
原作者新建了一個(gè)項(xiàng)目叫nocrazy。 于是路徑為gittest/nocrazy
做了兩次提交
提交一：
a.txt
this is a
提交二：b.txt
this is b.
2. 我cyper某天fork了這個(gè)項(xiàng)目，于是有origin指向uniquejava/nocrazy, 并且新增一個(gè)upstream指向原作者gittest/nocrazy
$ git clone https://git.oschina.net/uniquejava/nocrazy.git
$ cd nocrazy
nocrazy git:(master) $ git remote add upstream https://git.oschina.net/gittest/nocrazy.git
nocrazy git:(master) $ git remote -v
origin https://git.oschina.net/uniquejava/nocrazy.git (fetch)
origin https://git.oschina.net/uniquejava/nocrazy.git (push)
upstream https://git.oschina.net/gittest/nocrazy.git (fetch)
upstream https://git.oschina.net/gittest/nocrazy.git (push)
nocrazy git:(master) $
3. gittest正常提交了一個(gè)新版本
c.txt
this is c
git log --oneline
e63667b this is c
11f5850 this is b
1cbdb56 this is a
4. Cyper想把fork同步到和gittest一模一樣，怎么辦？
辦法一(思考未試驗(yàn)）：把自己的fork刪除重新fork? 然后呢在本地git pull origin master
辦法二：
git fetch upstream
git checkout master
git merge upstream/master
方法二需要push才能到origin么。(yes)
nocrazy git:(master) $ ll
total 16
drwxr-xr-x 13 cyper staff 442B Aug 26 05:11 .git/
-rw-r--r-- 1 cyper staff 10B Aug 26 05:07 a.txt
-rw-r--r-- 1 cyper staff 10B Aug 26 05:07 b.txt
nocrazy git:(master) $ git fetch upstream
remote: Counting objects: 4, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 0), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
From https://git.oschina.net/gittest/nocrazy
* [new branch] master -> upstream/master
nocrazy git:(master) $ git diff ..upstream/master
diff --git a/c.txt b/c.txt
new file mode 100644
index 0000000..5da75cf
--- /dev/null
+++ b/c.txt
@@ -0,0 +1 @@
+this is c
使用以上git diff命令可以看到author新增了一個(gè)c.txt文件。
nocrazy git:(master) $ git merge upstream/master
Updating 11f5850..e63667b
Fast-forward
c.txt | 1 +
1 file changed, 1 insertion(+)
create mode 100644 c.txt
nocrazy git:(master) $ git status
On branch master
Your branch is ahead of 'origin/master' by 1 commit.
(use "git push" to publish your local commits)
nothing to commit, working directory clean
nocrazy git:(master) $ git fetch upstream
nocrazy git:(master) $ git merge upstream/master
Already up-to-date.
nocrazy git:(master) $ git diff ..origin/master
diff --git a/c.txt b/c.txt
deleted file mode 100644
index 5da75cf..0000000
--- a/c.txt
+++ /dev/null
@@ -1 +0,0 @@
-this is c
通過以上可以看到git merge只是把upstream上的代碼拉到(本地工作目錄+本地倉庫)，需要我們push origin
nocrazy git:(master) $ git push origin master
Username for 'https://git.oschina.net': uniquejava
Password for 'https://uniquejava@git.oschina.net':
Counting objects: 3, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 292 bytes | 0 bytes/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To https://git.oschina.net/uniquejava/nocrazy.git
11f5850..e63667b master -> master
nocrazy git:(master) $ ll
total 24
drwxr-xr-x 14 cyper staff 476B Aug 26 05:21 .git/
-rw-r--r-- 1 cyper staff 10B Aug 26 05:07 a.txt
-rw-r--r-- 1 cyper staff 10B Aug 26 05:07 b.txt
-rw-r--r-- 1 cyper staff 10B Aug 26 05:14 c.txt
到這里， 步驟4驗(yàn)證結(jié)束。。。成功的將fork上的代碼更新到最新版。
5. 假設(shè)上一步成功執(zhí)行， 效果應(yīng)該和我重新fork一遍最新的項(xiàng)目是一樣的。
6. 重復(fù)3:即gitetst提交了一個(gè)新版本
d.txt
this is d.
7. 在6之前，Cyper因?yàn)橐迯?fù)defect #1, 已經(jīng)開始基于c.txt做修改。就沒有來得及及時(shí)同步
cyper修改this is c變成this is c_cyper
然后正常的add, commit ， （Cyper此時(shí)是否可以push?)
nocrazy git:(master) ? $ git commit -m "[nocrazy-1] fix c."
[master 77fd57f] [nocrazy-1] fix c.
1 file changed, 1 insertion(+), 1 deletion(-)
此時(shí)已經(jīng)有了分歧。gittest上有新的提交， cyper也有新的提交。
cyper想基于最新的代碼重新提交。
7-1 假定cyper沒有push
他想先更新fork，然后基于 author最新的代碼去做提交
git fetch upstream
git checkout master
git merge upstream/master 這一步是用git rebase upstream/master還是用git merge upstream/master
=====
nocrazy git:(master) $ git rebase origin/master(這步只是想驗(yàn)證base到當(dāng)前base的情況，無效果）
Current branch master is up to date.
nocrazy git:(master) $ git fetch upstream
remote: Counting objects: 4, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 1), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
From https://git.oschina.net/gittest/nocrazy
e63667b..380a8dd master -> upstream/master
nocrazy git:(master) $ git rebase upstream/master
First, rewinding head to replay your work on top of it...
Applying: [nocrazy-1] fix c.
nocrazy git:(master) $ git status
On branch master
Your branch is ahead of 'origin/master' by 2 commits.
(use "git push" to publish your local commits)
nothing to commit, working directory clean
nocrazy git:(master) $
以上這步做了什么？？？原來git rebase upstream/master把upstream上的代碼拉到(本地工作目錄+本地倉庫)，并且自動(dòng)做了合并， 所以你的本了一下子多出來兩個(gè)commit需要push, 因此有Your branch is ahead of 'origin/master' by 2 commits.
nocrazy git:(master) $ git log --oneline
8530647 [nocrazy-1] fix c.
380a8dd this is d
e63667b this is c
11f5850 this is b
1cbdb56 this is a
現(xiàn)在只需做push origin。。。就行了！
nocrazy git:(master) $ git push origin master
Username for 'https://git.oschina.net': uniquejava
Password for 'https://uniquejava@git.oschina.net':
Counting objects: 6, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (6/6), 566 bytes | 0 bytes/s, done.
Total 6 (delta 1), reused 0 (delta 0)
To https://git.oschina.net/uniquejava/nocrazy.git
e63667b..8530647 master -> master
所以在發(fā)pull request 之前不要去做push . (如果在rebase之前就做了push，需要怎么補(bǔ)救？？？）
到目前為止，cyper的遠(yuǎn)程倉庫中是最新的代碼，而原作者的代碼不新，因?yàn)樗拇a沒有包含你的修改
8. 發(fā)pull request
8-1， 假設(shè)gittest在你發(fā)pull request前，沒有提交任何代碼。。
過程很簡(jiǎn)單。
接下來gittest review，他點(diǎn)擊某個(gè)代碼變動(dòng)行的前面加了一個(gè)comment: 少了一個(gè)標(biāo)點(diǎn)符號(hào) 。。
如果你此時(shí)使用git fetch upstream會(huì)沒有任何輸出
然后你
nocrazy git:(master) $ git rebase upstream/master
Current branch master is up to date.
這是因?yàn)槟惝?dāng)前沒有任何commit是需要rebase的, 因?yàn)樗衏ommit都已經(jīng)push到了origin. 除非。。
與時(shí)同時(shí)， gittest正常添加了一個(gè)新文件
e.txt
this is e.
你重新fetch,
nocrazy git:(master) $ git fetch upstream
remote: Counting objects: 5, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 1), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
From https://git.oschina.net/gittest/nocrazy
380a8dd..fd2e641 master -> upstream/master
nocrazy git:(master) $ git diff ..upstream/master
diff --git a/c.txt b/c.txt
index 3af12b3..5da75cf 100644
--- a/c.txt
+++ b/c.txt
@@ -1 +1 @@
-this is c_cyper
+this is c
diff --git a/e.txt b/e.txt
new file mode 100644
index 0000000..5641475
--- /dev/null
+++ b/e.txt
@@ -0,0 +1 @@
可以看到，當(dāng)前你的本地倉庫和upstream的區(qū)別是。。你改了c文件而upstream加了e文件。。
你重新rebase
nocrazy git:(master) $ git rebase upstream/master
First, rewinding head to replay your work on top of it...
Applying: [nocrazy-1] fix c.
nocrazy git:(master) $ git status
On branch master
Your branch and 'origin/master' have diverged,
and have 2 and 1 different commit each, respectively.
(use "git pull" to merge the remote branch into yours)
nothing to commit, working directory clean
nocrazy git:(master) $
這時(shí)和第一次有所不一樣,
nocrazy git:(master) $ git log --oneline
8c4c4b6 [nocrazy-1] fix c.
fd2e641 this is e
380a8dd this is d
e63667b this is c
11f5850 this is b
1cbdb56 this is a
查看一下有什么不一樣
nocrazy git:(master) $ git diff ..origin/master
diff --git a/e.txt b/e.txt
deleted file mode 100644
index 5641475..0000000
--- a/e.txt
+++ /dev/null
@@ -1 +0,0 @@
-this is e
是因?yàn)槟阕约旱倪h(yuǎn)程倉庫沒有包含e文件。。。按照提示。 你需要做一次pull
但是pull會(huì)產(chǎn)生分支 。。
嘗試一下然后立馬撤銷（http://stackoverflow.com/questions/1223354/undo-git-pull-how-to-bring-repos-to-old-state）
nocrazy git:(master) $ git pull
Merge made by the 'recursive' strategy.
nocrazy git:(master) $ git log --oneline
9d7a324 Merge branch 'master' of https://git.oschina.net/uniquejava/nocrazy
8c4c4b6 [nocrazy-1] fix c.
fd2e641 this is e
8530647 [nocrazy-1] fix c.
380a8dd this is d
e63667b this is c
11f5850 this is b
1cbdb56 this is a
nocrazy git:(master) $ git status
On branch master
Your branch is ahead of 'origin/master' by 3 commits.
(use "git push" to publish your local commits)
nothing to commit, working directory clean
可見， git pull生成的commit history多么的混亂！(相對(duì)于當(dāng)前的origin/master,
一下子多出了3條commit history)
9d7a324 Merge branch 'master' of https://git.oschina.net/uniquejava/nocrazy
8c4c4b6 [nocrazy-1] fix c.
fd2e641 this is e
趕緊撤銷并換成git rebase
nocrazy git:(master) $ git show HEAD
commit 9d7a324e5e562475b9585ed029817fc98d09a1d4
Merge: 8c4c4b6 8530647
Author: cyper <345343747@qq.com>
Date: Wed Aug 26 06:11:07 2015 +0800
Merge branch 'master' of https://git.oschina.net/uniquejava/nocrazy
原來。。HEAD并不是指向遠(yuǎn)程倉庫的head..
nocrazy git:(master) $ git show head
nocrazy git:(master) $ git show HEAD
nocrazy git:(master) $ git show master
nocrazy git:(master) $ git show origin/master
。。。前三個(gè)信息都是指向本地倉庫的頭，是沒一個(gè)commit id.最后一個(gè)是我想要的頭，是我pull之前的commit id
所以有三種方法
git reset --hard HEAD^3
或git reset --hard origin/master
或者git reset --hard 8530647b
重做第7步。。
nocrazy git:(master) $ git rebase upstream/master
First, rewinding head to replay your work on top of it...
Applying: [nocrazy-1] fix c.
nocrazy git:(master) $ git status
On branch master
Your branch and 'origin/master' have diverged,
and have 2 and 1 different commit each, respectively.
(use "git pull" to merge the remote branch into yours)
nothing to commit, working directory clean
nocrazy git:(master) $
現(xiàn)在因?yàn)楸镜貍}庫才是最新的。。你需要force push到origin而不需要理pull操作。。。
nocrazy git:(master) $ git push origin master --force
Username for 'https://git.oschina.net': uniquejava
Password for 'https://uniquejava@git.oschina.net':
Counting objects: 6, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (6/6), 569 bytes | 0 bytes/s, done.
Total 6 (delta 1), reused 0 (delta 0)
To https://git.oschina.net/uniquejava/nocrazy.git
+ 8530647...3e23afc master -> master (forced update)
git rebase產(chǎn)生了完美的commit history:
3e23afc [nocrazy-1] fix c.
fd2e641 this is e
380a8dd this is d
e63667b this is c
11f5850 this is b
1cbdb56 this is a
聯(lián)系客服
