把两个 Git 仓库合并起来

缘起

本人主题使用 hexo-theme-butterfly: 🦋 A Hexo Theme: Butterfly ，但是在此基础上又做了一些自定义。用过一段时间之后，作者的源仓库可能更新了很多没有的功能。之前的时候，每次都是手动 compare 并合并的，但是实践了两次之后，发现存在以下问题：

每次升级十分耗时
自己定义的功能在合并时可能丢失或遗漏

鉴于此，本文尝试使用一种较为智能的方式解决以上问题。

TL,DR

要想将源仓库（origin repo）合入（dest repo）中，那么可以将（origin repo）伪造成（dest repo）仓库的一个分支，然后合并到（dest repo）仓库中的指定分支（本文为 dev）。

工作流程

克隆目标仓库

git clone https://github.com/imoyao/hexo-theme-butterfly.git imoyao

克隆源仓库

git clone https://github.com/jerryc127/hexo-theme-butterfly.git

将源目录（jerryc）作为远程仓库添加到目标仓库（imoyao），并命名为jerryc
git remote add jerryc ../jerryc

从源仓库下载数据到本仓库

$ git fetch jerryc

remote: Enumerating objects: 139, done.
remote: Counting objects: 100% (137/137), done.
remote: Compressing objects: 100% (28/28), done.
remote: Total 58 (delta 45), reused 43 (delta 30)
Unpacking objects: 100% (58/58), done.
From ../jerryc
 * [new branch]      dev        -> jerryc/dev

git fetch
Git - git-fetch Documentation

git-fetch - Download objects and refs from another repository
git fetch 是将远程主机的最新内容拉到本地，用户在检查了以后决定是否合并到工作本机分支中。

而 git pull 则是将远程主机的最新内容拉下来后直接合并，即：git pull = git fetch + git merge，这样可能会产生冲突，需要手动解决。

查看此时仓库信息

$ git log
commit 88b1cc553ce3c2b5e53dccb2ff259ddb078c333b (HEAD -> dev, origin/dev, origin/HEAD)
Author: Jerry <***@gmail.com>
commit 88b1cc553ce3c2b5e53dccb2ff259ddb078c333b (HEAD -> dev, origin/dev, origin
/HEAD)
Author: Jerry <***@gmail.com>
Date:   Sat Nov 21 00:27:01 2020 +0800

# 省略内容

commit 88b1cc553ce3c2b5e53dccb2ff259ddb078c333b (HEAD -> dev, origin/dev, origin
/HEAD)
Author: Jerry <***@gmail.com>
Date:   Sat Nov 21 00:27:01 2020 +0800

# 省略内容

commit 7f03c3f71696fde1f1d3f1e969844ecde3d7f805
Author: Jerry <***@gmail.com>
Date:   Tue Nov 3 22:20:16 2020 +0800

# 省略内容

```plain
7. 将源仓库下载下来的 dev 分支作为新分支 checkout 到目标分支`updatedev`
```bash
git checkout -b updatedev jerryc/dev

Switched to a new branch 'updatedev'
Branch 'updatedev' set up to track remote branch 'dev' from 'jerryc'.

此时分支状态

$ git branch

  dev           # 我的开发分支
  master        # 我的主分支
* updatedev     # 作者和我的fetch之后的分支

切换到我的dev分支

git checkout dev

此时分支状态

$ git branch

* dev
  master
  updatedev

合并fetch的分支代码到我的dev分支

$ git merge updatedev

Updating 88b1cc5..dc1c7c5
Fast-forward
 _config.yml                                        |  6 +-
 languages/default.yml                              |  6 +-
 languages/en.yml                                   |  2 +
 languages/zh-CN.yml                                |  4 +-
# 中间省略
 source/css/_mode/readmode.styl                     | 19 +++--
 source/js/main.js                                  | 91 ++++++++++++++++------
 source/js/utils.js                                 | 13 +++-
 31 files changed, 374 insertions(+), 169 deletions(-)
 create mode 100644 layout/includes/third-party/newest-comments/twikoo-comment.pug

补充：如果遇到如下报错：

fatal: refusing to merge unrelated histories

那么可以git merge时加上--allow-unrelated-histories后缀：

git merge repo1 --allow-unrelated-histories

查看合并后代码

$ git log
commit dc1c7c5efdbb92de10a44cec2e15d16b84823ce7 (HEAD -> dev, jerryc/dev, updatedev)
Merge: 02af307 97fe932
Author: Jerry Wong <***@gmail.com>
Date:   Mon Dec 7 21:17:09 2020 +0800

# 省略内容

commit 97fe932ad9c22fa4b5690d38b33242eed11742f0
Author: 零度冷咖啡 <***@outlook.com>
Date:   Mon Dec 7 08:25:02 2020 +0800

# 省略内容

commit 01e7929c02a5fd018ab3171a381487a78f2df05c
Merge: 7c3945f 02af307
Author: 零度冷咖啡 <***@outlook.com>
Date:   Mon Dec 7 08:22:17 2020 +0800

# 省略内容

commit 02af3077e71d02071ad3c7e8b159149310597513
Author: Jerry <***@gmail.com>
Date:   Sat Dec 5 22:28:54 2020 +0800

# 省略内容

commit 88b1cc553ce3c2b5e53dccb2ff259ddb078c333b (origin/dev, origin/HEAD)
Author: Jerry <***@gmail.com>
Date:   Sat Nov 21 00:27:01 2020 +0800

# 省略内容

横向拼图参考此处

删除无用的fetch分支updatedev

$ git branch -D updatedev

Deleted branch updatedev (was dc1c7c5).

提交到远程仓库

Administrator@PC201803221826 MINGW64 /h/mycode/butterfly/imoyao (dev)
$ git add .

Administrator@PC201803221826 MINGW64 /h/mycode/butterfly/imoyao (dev)
$ git commit -m 'updatedev'
On branch dev
Your branch is ahead of 'origin/dev' by 4 commits.
  (use "git push" to publish your local commits)

nothing to commit, working tree clean

Administrator@PC201803221826 MINGW64 /h/mycode/butterfly/imoyao (dev)
$ git push
Total 0 (delta 0), reused 0 (delta 0)
To https://github.com.cnpmjs.org/imoyao/hexo-theme-butterfly.git
   88b1cc5..dc1c7c5  dev -> dev

同样的道理，我们可以把master分支与原作者保持同步。这个留给读者去实践练习。

更上一层楼

把我自己修改的合并到我的仓库中。

初始化为仓库（否则无法执行 git 合并）

$ git init

Initialized empty Git repository in H:/mycode/butterfly/masantu/.git/

在 masantu 仓库中 add 并 commit 代码作为一次提交
git add .
git commit -m 'init mycode to repo'
添加远程仓库masantu并命名为masantu
关于这条命令的解释Git - git-remote Documentation
git remote add [shortname] [url]
Add a remote named for the repository at . The command git fetch can then be used to create and update remote-tracking branches /.
$ git remote add masantu ../masantu

将masantu仓库的代码拉到imoyao仓库中

$ git fetch masantu
warning: no common commits
remote: Enumerating objects: 261, done.
remote: Counting objects: 100% (261/261), done.
remote: Compressing objects: 100% (259/259), done.
remote: Total 261 (delta 18), reused 0 (delta 0)
Receiving objects: 100% (261/261), 259.62 KiB | 1.08 MiB/s, done.
Resolving deltas: 100% (18/18), done.
From ../masantu
 * [new branch]      master     -> masantu/master

以masantu/master作为基准新建分支upmst(updatemasantu 的简写)

$ git checkout -b upmst masantu/master
Switched to a new branch 'upmst'
Branch 'upmst' set up to track remote branch 'master' from 'masantu'.

此时分支状态

$ git branch

  dev
* upmst
  master

切换分支到dev

$ git checkout dev
Switched to branch 'dev'
Your branch is up to date with 'origin/dev'.

$ git branch

* dev
  upmst
  master

合并masantu分支到dev

git merge upmst --allow-unrelated-histories

CONFLICT (add/add): Merge conflict in source/js/utils.js
Auto-merging source/js/utils.js
# 省略内容
Auto-merging source/css/_global/function.styl
CONFLICT (add/add): Merge conflict in package.json