奇怪的`git mv`行为

Question

上个月，我开始贡献一个GitHub仓库，通过分叉相应的回购，创建一个功能分支，然后提交一个pull请求。在重复此过程几天的过程中，当使用预安装的Linux命令mv以及Git命令git mv重命名文件时，我遇到了一个奇怪的问题。

实际的问题是，这取决于当你移动/上重命名文件与git mv，当你git add它和在什么时候你编辑重命名的文件，你要么：

On branch master 
Changes to be committed: 
    (use "git reset HEAD <file>..." to unstage) 

     renamed: somethingelse -> something 

或者这样：

On branch master 
Changes to be committed: 
    (use "git reset HEAD <file>..." to unstage) 

     new file: something 
     deleted: somethingelse 

为了证明这一点，我已经写了test：

#!/bin/bash 

# To my knowledge, this “problem” only occurs with new files in a Git repo 
printf "COMMAND: mkdir -v gitrepo\n\n" 
mkdir -v gitrepo 

printf "\nCOMMAND: cd gitrepo\n\n" 
cd gitrepo 

printf "\nCOMMAND: git init\n\n" 
git init 

printf "\nCOMMAND: git status\n\n" 
git status 

printf "\nCOMMAND: touch something\n\n" 
touch something 

printf "\nCOMMAND: git status\n\n" 
git status 

printf "\nCOMMAND: git add something\n\n" 
git add something 

printf "\nCOMMAND: git status\n\n" 
git status 

printf '\nCOMMAND: git commit -m "Added something"\n\n' 
git commit -m "Added something" 

printf "\nCOMMAND: git status\n\n" 
git status 

printf "\nCOMMAND: git mv something somethingelse\n\n" 
git mv something somethingelse 

printf "\nCOMMAND: git status\n\n" 
git status 

# Type in the following on line 1: First line of code 
printf "\nCOMMAND: vim somethingelse\n\n" 
vim somethingelse 

printf "\nCOMMAND: git status\n\n" 
git status 

printf "\nCOMMAND: git add somethingelse\n\n" 
git add somethingelse 

printf "\nCOMMAND: git status\n\n" 
git status 

printf '\nCOMMAND: git commit -m "Renamed something to somethingelse and edited somethingelse"\n\n' 
git commit -m "Renamed something to somethingelse and edited somethingelse" 

printf "\nCOMMAND: git status\n\n" 
git status 

printf "\nCOMMAND: git mv somethingelse something\n\n" 
git mv somethingelse something 

printf "\nCOMMAND: git status\n\n" 
git status 

# If you add something to the first line, the rename will not be detected by Git 
# However, if you instead create 2 newlines and fill line 3 with new code, 
# the rename gets detected for whatever reason 
printf "\nCOMMAND: vim something\n\n" 
vim something 

printf "\nCOMMAND: git status\n\n" 
git status 

printf "\nCOMMAND: git add something\n\n" 
git add something 

printf "\nCOMMAND: git status\n\n" 
git status 

printf '\nCOMMAND: git commit -m "Renamed somethingelse to something and edited something"\n\n' 
git commit -m "Renamed somethingelse to something and edited something" 

printf "\nCOMMAND: git status\n\n" 
git status 

cd .. && rm -fr gitrepo && printf "\nREMOVED gitrepo folder\n" 
printf "\nDONE.\n" 

出于某种原因，这主要影响“新文件”，而不是已存在于存储库中的文件。例如，如果您将Spoon-Knife repository的分支克隆为git clone https://github.com/christianheinrichs/Spoon-Knife.git，然后应用链接测试脚本的工作流程，您将看到在大多数情况下，您将能够将README.md文件重命名为README，例如对其进行编辑，它仍然算作重命名而不是新文件/删除分割。

尽管我可以在克隆的勺子刀叉回购中重现新文件/删除行为，但我不确定我是如何做到这一点的，并且当我说我试图弄清楚时相信我。

那么究竟发生了什么，我不明白？

参见：https://gist.github.com/christianheinrichs/e50bfdd5eec70a606fa6ce4a88c5951b#file-git_mv-test-sh-L65

Answer 1

git不保留一个标志说：“这newname文件最初被称为oldname文件”：

git mv oldname newname 

# is exactly equivalent to : 

mv oldname newname 
git rm oldname 
git add newname 

当显示文件的状态，git试图猜测，如果它是rename或delete + add通过比较文件的内容，并看到它们是多么相似。所以：如果你从git mv开始文件，然后编辑文件，取决于文件被修改了多少，git可能会或可能不会看到它全部以mv开头。

又见这个问题的答案：How does Git know that file was renamed?