奇怪的`git mv`行爲

Question

上個月，我開始貢獻一個GitHub倉庫，通過分叉相應的回購，創建一個功能分支，然後提交一個pull請求。在重複此過程幾天的過程中，當使用預安裝的Linux命令mv以及Git命令git mv重命名文件時，我遇到了一個奇怪的問題。

實際的問題是，這取決於當你移動/上重命名文件與git mv，當你git add它和在什麼時候你編輯重命名的文件，你要麼：

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

     renamed: somethingelse -> something 

或者這樣：

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

     new file: something 
     deleted: somethingelse 

爲了證明這一點，我已經寫了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" 

出於某種原因，這主要影響「新文件」，而不是已存在於存儲庫中的文件。例如，如果您將Spoon-Knife repository的分支克隆爲git clone https://github.com/christianheinrichs/Spoon-Knife.git，然後應用鏈接測試腳本的工作流程，您將看到在大多數情況下，您將能夠將README.md文件重命名爲README，例如對其進行編輯，它仍然算作重命名而不是新文件/刪除分割。

儘管我可以在克隆的勺子刀叉回購中重現新文件/刪除行爲，但我不確定我是如何做到這一點的，並且當我說我試圖弄清楚時相信我。

那麼究竟發生了什麼，我不明白？

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

Answer 1

git不保留一個標誌說：「這newname文件最初被稱爲oldname文件」：

git mv oldname newname 

# is exactly equivalent to : 

mv oldname newname 
git rm oldname 
git add newname 

當顯示文件的狀態，git試圖猜測，如果它是rename或delete + add通過比較文件的內容，並看到它們是多麼相似。所以：如果你從git mv開始文件，然後編輯文件，取決於文件被修改了多少，git可能會或可能不會看到它全部以mv開頭。

又見這個問題的答案：How does Git know that file was renamed?