Git copy file preserving history [duplicate]

All you have to do is:

1. move the file to two different locations,
2. merge the two commits that do the above, and
3. move one copy back to the original location.

You will be able to see historical attributions (using git blame) and full history of changes (using git log) for both files.

Suppose you want to create a copy of file foo called bar. In that case the workflow you’d use would look like this:

git mv foo bar
git commit

SAVED=`git rev-parse HEAD`
git reset --hard HEAD^
git mv foo copy
git commit

git merge $SAVED     # This will generate conflicts
git commit -a        # Trivially resolved like this

git mv copy foo
git commit

Why this works

After you execute the above commands, you end up with a revision history that looks like this:

( revision history )            ( files )

    ORIG_HEAD                      foo
     /     \                      /   \
SAVED       ALTERNATE          bar     copy
     \     /                      \   /
      MERGED                     bar,copy
        |                           |
     RESTORED                    bar,foo

When you ask Git about the history of foo, it will:

1. detect the rename from copy between MERGED and RESTORED,
2. detect that copy came from the ALTERNATE parent of MERGED, and
3. detect the rename from foo between ORIG_HEAD and ALTERNATE.

From there it will dig into the history of foo.

When you ask Git about the history of bar, it will:

1. notice no change between MERGED and RESTORED,
2. detect that bar came from the SAVED parent of MERGED, and
3. detect the rename from foo between ORIG_HEAD and SAVED.

From there it will dig into the history of foo.

It’s that simple. 🙂

You just need to force Git into a merge situation where you can accept two traceable copies of the file(s), and we do this with a parallel move of the original (which we soon revert).