Git revert after code moved to another file

TL;DR

1. git show -R <commit> > revert.patch to generate a reverse patch
2. patch <file> revert.patch to apply the patch to the correct file (the one where the code was moved to)

Reverting a commit

git revert undoes changes done in some earlier commit. It assumes the files are still in the same place, and the code has not been moved around.

$ git commit -m "feat: risky feature"
[main e86576e] feat: risky feature
 1 file changed, 1 insertion(+), 1 deletion(-)

$ git revert HEAD --no-edit
[main b0eb58b] Revert "feat: risky feature"
 Date: Fri May 9 21:26:20 2025 +0200
 1 file changed, 1 insertion(+), 1 deletion(-)

$ git log -n 1
commit b0eb58b496ac695bc33a1f03d4363da56692ed28
Author: Grzegorz Rozdzialik <voreny.gelio@gmail.com>
Date:   Fri May 9 21:26:20 2025 +0200

    Revert "feat: risky feature"

    This reverts commit e86576e2db771f7f4898be48590f98b841babee9.

What if you want to revert an earlier commit, and the code has been moved to another file in the meantime?

Reverting after a file was renamed

If the entire file was moved, then git will most likely be smart enough to notice that was a file rename/move (notice the rename in the git commit output below), and it will git revert will work just fine.

$ git commit -m "chore: move journal"
[main 6dbc8f9] chore: move journal
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename journal.txt => journal-2.tx (100%)

$ git revert HEAD~ --no-edit
[main e30fd93] Revert "feat: risky feature"
 1 file changed, 1 insertion(+), 1 deletion(-)

Dealing with moved code

Problems happen when only part of the code was moved, e.g. when a file was sliced and some code was extracted. Then, git will not know what to do, and git revert will refuse to work.

$ git revert HEAD~
Auto-merging Header.tsx
CONFLICT (content): Merge conflict in Header.tsx
error: could not revert 8409ca0... refactor: change styles
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git revert --continue".
hint: You can instead skip this commit with "git revert --skip".
hint: To abort and get back to the state before "git revert",
hint: run "git revert --abort".

$ git diff
diff --cc Header.tsx
index e6629be,52520cd..0000000
--- a/Header.tsx
+++ b/Header.tsx
@@@ -98,6 -97,16 +98,30 @@@ const GitHubIcon = () =>
    );
  };

++<<<<<<< HEAD
++||||||| 8409ca0 (refactor: change styles)
++const StyledIconLink = styled("a")(({ theme }) => ({
++  textDecoration: "none",
++  transition: "filter ease-in-out 200ms",
++  "--shadowRadius": "5px",
++  filter: `drop-shadow(0 0 var(--shadowRadius) ${theme.color.shadow()})`,
++  ":hover": {
++    "--shadowRadius": "10px",
++  },
++}));
++
++=======
+ const StyledIconLink = styled("a")(({ theme }) => ({
+   textDecoration: "none",
+   transition: "filter ease-in-out 200ms",
+   "--shadowRadius": "1px",
+   filter: `drop-shadow(0 0 var(--shadowRadius) ${theme.color.shadow()})`,
+   ":hover": {
+     "--shadowRadius": "2px",
+   },
+ }));
+
++>>>>>>> parent of 8409ca0 (refactor: change styles)
  const RSSIcon = () => {
    const theme = useTheme();
    const size = theme.spacing(3);

The output is pretty unhelpful. It tries to revert the change, but the code is no longer there.

I know that I moved the code to StyledIconLink.tsx. I would love to tell git revert to try to apply that revert patch not to Header.tsx, but to StyledIconLink.tsx. The way to do that is to:

1. Generate a reverse patch (e.g. using git show -R)
2. Apply that patch manually to the correct file using patch

$ git show -R HEAD~ > revert.patch
$ patch StyledIconLink.tsx revert.patch
patching file StyledIconLink.tsx
No such line 37 in input file, ignoring
1 out of 2 hunks failed--saving rejects to StyledIconLink.tsx.rej

The patch command:

• reverted as much of StyledIconLink.tsx as it could

  $ git diff
  diff --git a/StyledIconLink.tsx b/StyledIconLink.tsx
  index d95a425..f8e0e1d 100644
  --- a/StyledIconLink.tsx
  +++ b/StyledIconLink.tsx
  @@ -1,9 +1,9 @@
   export const StyledIconLink = styled("a")(({ theme }) => ({
     textDecoration: "none",
     transition: "filter ease-in-out 200ms",
  -  "--shadowRadius": "5px",
  +  "--shadowRadius": "1px",
     filter: `drop-shadow(0 0 var(--shadowRadius) ${theme.color.shadow()})`,
     ":hover": {
  -    "--shadowRadius": "10px",
  +    "--shadowRadius": "2px",
     },
   }));
  

• said that it could not revert everything, and reported that in StyledIconLink.tsx.rej - makes sense, because that commit changed code outside of StyledIconLink.tsx as well. This shows which other code I need to revert manually.

  $ cat StyledIconLink.tsx.rej
  @@ -38,7 +38,7 @@
  href={githubProfileLink}
  target="_blank"
      rel="noopener"
      -          aria-label="GitHub profile"
      +          aria-label="My GitHub profile"
      >
      <GitHubIcon />
      </StyledIconLink>
  

• created a StyledIconLink.tsx.orig file with the original contents of the file (pre-patch). This is most likely pointless, because you are already using git, so you can easily go back to the original content of StyledIconLink.tsx.

Switcheroo: generate a normal patch, and patch in reverse

Instead of tucking the -R flag to the git show command, you can also add it to the patch command:

git show HEAD~ > normal.patch
patch -R StyledIconLink.tsx normal.patch

This has the same effect. Choose whichever you prefer.