[git] Handling file renames in git

I'd read that when renaming files in git, you should commit any changes, perform your rename and then stage your renamed file. Git will recognise the file from the contents, rather than seeing it as a new untracked file, and keep the change history.

However, doing just this tonight I ended up reverting to git mv.

> $ git status
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   modified:   index.html
#

Rename my stylesheet in Finder from iphone.css to mobile.css

> $ git status
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   modified:   index.html
#
# Changed but not updated:
#   (use "git add/rm <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   deleted:    css/iphone.css
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#   css/mobile.css

So git now thinks I've deleted one CSS file, and added a new one. Not what I want, lets undo the rename and let git do the work.

> $ git reset HEAD .
Unstaged changes after reset:
M   css/iphone.css
M   index.html

Back to where I began.

> $ git status
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   modified:   index.html
#

Lets use git mv instead.

> $ git mv css/iphone.css css/mobile.css
> $ git status
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   renamed:    css/iphone.css -> css/mobile.css
#
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   modified:   index.html
#

Looks like we're good. So why didn't git recognise the rename the first time around when I used Finder?

Step1: rename the file from oldfile to newfile

git mv #oldfile #newfile

Step2: git commit and add comments

git commit -m "rename oldfile to newfile"

Step3: push this change to remote sever

git push origin #localbranch:#remotebranch

you have to git add css/mobile.css the new file and git rm css/iphone.css, so git knows about it. then it will show the same output in git status

you can see it clearly in the status output (the new name of the file):

# Untracked files:
#   (use "git add <file>..." to include in what will be committed)

and (the old name):

# Changed but not updated:
#   (use "git add/rm <file>..." to update what will be committed)

i think behind the scenes git mv is nothing more than a wrapper script which does exactly that: delete the file from the index and add it under a different name

You have to add the two modified files to the index before git will recognize it as a move.

The only difference between mv old new and git mv old new is that the git mv also adds the files to the index.

mv old new then git add -A would have worked, too.

Note that you can't just use git add . because that doesn't add removals to the index.

See Difference between "git add -A" and "git add ."

Best thing is to try it for yourself.

mkdir test
cd test
git init
touch aaa.txt
git add .
git commit -a -m "New file"
mv aaa.txt bbb.txt
git add .
git status
git commit --dry-run -a

Now git status and git commit --dry-run -a shows two different results where git status shows bbb.txt as a new file/ aaa.txt is deleted, and the --dry-run commands shows the actual rename.

~/test$ git status

# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   new file:   bbb.txt
#
# Changes not staged for commit:
#   (use "git add/rm <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   deleted:    aaa.txt
#


/test$ git commit --dry-run -a

# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   renamed:    aaa.txt -> bbb.txt
#

Now go ahead and do the check-in.

git commit -a -m "Rename"

Now you can see that the file is in fact renamed, and what's shown in git status is wrong.

Moral of the story: If you're not sure whether your file got renamed, issue a "git commit --dry-run -a". If its showing that the file is renamed, you're good to go.

For Xcode users: If your rename your file in Xcode you see the badge icon change to append. If you do a commit using XCode you will actually create a new file and lose the history.

A workaround is easy but you have to do it before commiting using Xcode:

1. Do a git Status on your folder. You should see that the staged changes are correct:

renamed: Project/OldName.h -> Project/NewName.h renamed: Project/OldName.m -> Project/NewName.m

1. do commit -m 'name change'

Then go back to XCode and you will see the badge changed from A to M and it is save to commit furtur changes in using xcode now.

Let's think about your files from git perspective.

Keep in mind git doesn't track any metadata about your files

Your repository has (among others)

$ cd repo
$ ls
...
iphone.css
...

and it is under git control:

$ git ls-files --error-unmatch iphone.css &>/dev/null && echo file is tracked
file is tracked

Test this with:

$ touch newfile
$ git ls-files --error-unmatch newfile &>/dev/null && echo file is tracked
(no output, it is not tracked)
$ rm newfile

When you do

$ mv iphone.css mobile.css

From git perspective,

• there is no iphone.css (it is deleted -git warns about that-).
• there is a new file mobile.css.
• Those files are totally unrelated.

So, git advises about files it already knows (iphone.css) and new files it detects (mobile.css) but only when files are in index or HEAD git starts to check their contents.

At this moment, neither "iphone.css deletion" nor mobile.css are on index.

Add iphone.css deletion to index

$ git rm iphone.css

git tells you exactly what has happened: (iphone.css is deleted. Nothing more happened)

then add new file mobile.css

$ git add mobile.css

This time both deletion and new file are on index. Now git detects context are the same and expose it as a rename. In fact if files are 50% similar it will detect that as a rename, that let you change mobile.css a bit while keeping the operation as a rename.

See this is reproducible on git diff. Now that your files are on index you must use --cached. Edit mobile.css a bit, add that to index and see the difference between:

$ git diff --cached 

and

$ git diff --cached -M

-M is the "detect renames" option for git diff. -M stands for -M50% (50% or more similarity will make git express it as a rename) but you can reduce this to -M20% (20%) if you edit mobile.css a lot.

You didn't stage the results of your finder move. I believe if you did the move via Finder and then did git add css/mobile.css ; git rm css/iphone.css, git would compute the hash of the new file and only then realize that the hashes of the files match (and thus it's a rename).

In cases where you really have to rename the files manually, for eg. using a script to batch rename a bunch of files, then using git add -A . worked for me.

For git 1.7.x the following commands worked for me:

git mv css/iphone.css css/mobile.css
git commit -m 'Rename folder.' 

There was no need for git add, since the original file (i.e. css/mobile.css) was already in the committed files previously.

Git will recognise the file from the contents, rather than seeing it as a new untracked file

That's where you went wrong.

It's only after you add the file, that git will recognize it from content.

Just ran into this issue - if you updated a bunch of files and don't want to do git mv all of them this also works:

1. Rename parent directory from /dir/RenamedFile.js to /whatever/RenamedFile.js.
2. git add -A to stage that change
3. Rename parent directory back to /dir/RenamedFile.js.
4. git add -A again, will re-stage vs that change, forcing git to pick up the filename change.