背景
最近在用laravel开发微信小程序的接口，因为服务器PHP版本的问题，分别用了laravel 5.6(php 7.1，开发环境) 和 laravel 5.4 (php 5.6，服务器环境)，开发完成后，两个项目绝大部分的代码都差不多，不想再建一个仓库放php 5.6版的代码，便试着在原有仓库新建分支来存储php 5.6的项目，捣鼓的一上午终于搞出来了，现在记录下。
主要步骤：
- 在远程和本地仓库中新建一个分支（我建的是
laravel54）； - 删除远程
laravel54分支上的所有文件； - 将新项目的文件推送到
laravel54上。
流程
新建一个文件夹(我的是laravel5.4)
创建git本地仓库并关联远程仓库
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4
$ git init
Initialized empty Git repository in D:/PHP/xampp/htdocs/apple/laravel5.4/.git/
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master)
$ git remote add origin [email protected]
建立远程仓库分支 laravel54
注意，建立远程分支后，暂时还不能在本地建立其他分支，因为刚创建的git仓库默认的master分支要在第一次commit之后才会真正建立，这时创建其他分支会报错，解决办法在后面说明。
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master)
$ git branch laravel54
fatal: Not a valid object name: 'master'.
随便新建一个文件，里面可以不用写任何东西，然后commit
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master)
$ touch clearTheBranch
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master)
$ git add clearTheBranch
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master)
$ git commit -m'clean this branch'
[master (root-commit) c7c5349] clean this branch
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100644 clearTheBranch
推送之前先更新（下面的代码是最核心的代码）
新建的分支默认与master分支一样，所以要在推送之前先把分支上的内容拉下来。
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master)
$ git pull origin laravel54
warning: no common commits
remote: Enumerating objects: 2453, done.
remote: Counting objects: 100% (2453/2453), done.
remote: Compressing objects: 100% (2320/2320), done.
Receiviremote: Total 2453 (delta 1547), reused 229 (delta 89)
Receiving objects: 100% (2453/2453), 1.40 MiB | 1.38 MiB/s, done.
Resolving deltas: 100% (1547/1547), done.
From xxxxxxxxxxxxxxxxxxxxx
* branch laravel54 -> FETCH_HEAD
* [new branch] laravel54 -> origin/laravel54
fatal: refusing to merge unrelated histories
这个时候会报错，是正常现象，，原因是本地仓库和远程仓库不一样，有类似两者有完全不相同的commit历史，只需要在在pull的同时加上一行代码即可，代码如下：
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master)
$ git pull origin laravel54 --allow-unrelated-histories
From xxxxxxxxxxxxxxxxxxxxx
* branch laravel54 -> FETCH_HEAD
Merge made by the 'recursive' strategy.
......
这步操作的时候，会有merge的commit说明，简单写下，这个只是merge的说明，并不会真正和mater合并。
经过这一步操作，就已经把远程仓库laravel54分支里面的文件都拉下来了，接下来建立与远程仓库对应的本地分支。
建立并切换到本地分支 laravel54
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master)
$ git branch laravel54
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master)
$ git checkout laravel54
Switched to branch 'laravel54'
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54)
$
// 也可以直接用 git checkout -b laravel54
删除本地仓库里的所有文件（除了.git的文件夹），然后推送
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54)
$ git add .
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54)
$ git commit -m'delete all files'
[laravel54 d8bf12d] delete all files
215 files changed, 32019 deletions(-)
......
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54)
$ git push origin laravel54
Enumerating objects: 7, done.
Counting objects: 100% (7/7), done.
Delta compression using up to 4 threads.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (6/6), 683 bytes | 341.00 KiB/s, done.
Total 6 (delta 1), reused 1 (delta 0)
remote: Powered by Gitee.com
To xxxxxxxxxxxxxxxxxxxxx.git
c810298..d8bf12d laravel54 -> laravel54
这个时候，远程仓库的laravel54分支便和本地仓库的laravel54分支一样都是空白的，这样就可以随心所欲的推送了。
新项目推送
这时就可以把之前的项目拷进这个文件夹里面，然后按照正常的推送流程进行推送。
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54)
$ git add .
warning: LF will be replaced by CRLF in .env.example.
The file will have its original line endings in your working directory.
.......
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54)
$ git commit -m'laravel54 push'
[laravel54 eba0954] laravel54 push
113 files changed, 11583 insertions(+)
create mode 100644 .env.example
create mode 100644 .gitattributes
.......
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54)
$ git push origin laravel54
Enumerating objects: 152, done.
Counting objects: 100% (152/152), done.
Delta compression using up to 4 threads.
Compressing objects: 100% (126/126), done.
Writing objects: 100% (151/151), 211.43 KiB | 2.94 MiB/s, done.
Total 151 (delta 14), reused 42 (delta 4)
remote: Resolving deltas: 100% (14/14), done.
remote: Powered by Gitee.com
To xxxxxxxxxxxxxxxxxxxxx.git
d8bf12d..eba0954 laravel54 -> laravel54
小总结
不用担心推送错分支导致分支合并
经过如上操作，就可以实现master分支和laravel54是两个完全不同的项目，可以保持两个项目平行发展，因为两个分支的提交历史不一样，所以即便是误操作，提交错了分支，git会给出相应的报错，不会把两个分支直接合并，下面是代码演示：
-
本地laravel54向远程master分支推送
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54) $ touch a.txt 沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54) $ git add a.txt 沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54) $ git commit -m'test file a.txt' [laravel54 e246705] test file a.txt 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 a.txt 沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54) $ git push origin master To xxxxxxxxxxxxxxxxxxxxx.git ! [rejected] master -> master (fetch first) error: failed to push some refs to '[email protected]' 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. //本地版本回退 沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (laravel54) $ git log commit e246705e9894a658d3fb2ea8f51b1ee0dd8ff834 (HEAD -> laravel54) Author: muyan..." to include in what will be committed) a.txt nothing added to commit but untracked files present (use "git add" to track) -
本地master分支向远程master分支推送
沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master) $ git add a.txt 沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master) $ git commit -m 'test file a' [master d3e8bba] test file a 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 a.txt 沐@ MINGW64 /d/PHP/xampp/htdocs/apple/laravel5.4 (master) $ git push origin master To xxxxxxxxxxxxxxxxxxxxx.git ! [rejected] master -> master (fetch first) error: failed to push some refs to '[email protected]' 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.
理论上可以实现无限平行分支
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