git_err_00-Understanding of git pull-优快云博客

本文深入探讨了Git中fetch与merge命令的高级应用，解析了FETCH_HEAD的概念及其在多远程仓库场景下的作用。通过对比pull命令，强调了fetch与merge组合使用的优势，特别是在管理多个远程仓库时的灵活性和精确度。

ID = git_err_00

文章目录

Error
Analysis
Lesson learn
- Use `git fetch` + `git merge`^[1]
- FETCH_HEAD
Reference

Error

Misunderstood git pull

cmd = cmd1 + cmd2

stage	cmd	cmd1	cmd2
before	git pull	git fetch origin master	git merge origin master
after	git pull	git fetch origin master	git merge FETCH_HEAD

Analysis

pull from origin/master

$ git fetch origin master
From github.com:Shane-pe/hello-world
 * branch            master     -> FETCH_HEAD

$ git merge FETCH_HEAD
Already up to date.

pull from upgrade/master

$ git fetch upgrade master
From github.com:ShaneRun/hello-world
 * branch            master     -> FETCH_HEAD

$ git merge FETCH_HEAD
Already up to date.

Lesson learn

Use `git fetch` + `git merge`^[1]

This is very useful when you have more than 1 remote git address.

FETCH_HEAD

The key to understand git pull is to understand FETCH_HEAD`^[2]

而理解 fetch 的关键, 是理解 FETCH_HEAD.
这里需要解释下什么是FETCH_HEAD??
FETCH_HEAD指的是: 某个branch在服务器上的最新状态’.
每一个执行过fetch操作的项目’都会存在一个FETCH_HEAD列表,
这个列表保存在 .git/FETCH_HEAD 文件中, 其中每一行对应于远程服务器的一个分支.
当前分支指向的FETCH_HEAD, 就是这个文件第一行对应的那个分支.
一般来说, 存在两种情况:
如果没有显式的指定远程分支, 则远程分支的master将作为默认的FETCH_HEAD.
如果指定了远程分支, 就将这个远程分支作为FETCH_HEAD.