git rebase skips reapplied commits

If the same commit is made and then reverted on both <upstream> and <branch>, and then reapplied only on <branch>, then `git rebase <upstream> <branch>` will skip the reapplied commit.

The following script demonstrates the issue:

``` #!/bin/sh -eu

# Set up a repo for the following commands. repo_directory="./rebase-test-repo" rm -rf "${repo_directory}" mkdir -p "${repo_directory}" cd "${repo_directory}" git init -b main git config user.name test git config user.email test@no.mail

# Create a branch 'br' starting from a commit other than the tip of the # 'main' branch. Switch to it. git commit --allow-empty -m 'initial commit' git commit --allow-empty -m 'another empty commit' git switch --create br HEAD^

# Create a non-empty commit on 'br', then revert it. touch a git add a git commit -m 'Add a' git revert --no-edit HEAD

# Make identical commits on 'main'. git switch main touch a git add a git commit -m "Add a (on 'main')" git revert --no-edit HEAD

# Reapply the reverted commit to 'br'. git switch br git revert --no-edit HEAD

# Rebase 'br' onto 'main'. git rebase main br

git -P log --graph --all --oneline # Sample output: # # * 5b4d655 (HEAD -> br, main) Revert "Add a (on 'main')" # * 7881a38 Add a (on 'main') # * 907f1a8 another empty commit # * 6c094a9 initial commit # # What we expect to see: # The commit 'Reapply "Add a"' should have been rebased onto 'main'. # # What we see: # This commit was skipped during the rebase and has been lost. ```

Using the '--reapply-cherry-picks' option prevents this from happening, but it also creates empty commits, so it's not a proper workaround.

[System Info] git version: git version 2.48.1 cpu: x86_64 no commit associated with this build sizeof-long: 8 sizeof-size_t: 8 shell-path: /gnu/store/jlqbjxk51bdq5w7wlnbmwxm1j0pnllpx-bash-minimal-5.1.16/bin/sh zlib: 1.3 compiler info: gnuc: 11.4 libc info: glibc: 2.39 $SHELL (typically, interactive shell): /gnu/store/cdwviyfnsfv7k57qrwmym0mrynjixc1i-bash-5.1.16/bin/bash

[Enabled Hooks] not run from a git repository - no hooks to show