replay.md

Cherry-pick and revert

Repository::replay_commit applies one commit's change to the current HEAD (ReplayKind::CherryPick) or applies its inverse (ReplayKind::Revert). It reuses the bounded three-way tree and conflict-index machinery used by merge, and reads and writes exclusively through the repository filesystem adapter.

# use git_rs::{ReplayKind, ReplayOptions, Repository, Signature};
# fn example(repository: &Repository, commit: git_rs::ObjectId) -> git_rs::Result<()> {
let committer = Signature::new("Example", "example@example.com", 1, 0)?;
let result = repository.replay_commit(
    commit,
    ReplayKind::CherryPick,
    &ReplayOptions::default(),
    &committer,
)?;
# let _ = result;
# Ok(())
# }

A cherry-pick uses the selected commit parent as the base and the commit as theirs. A revert reverses those trees. Root commits use the empty tree. Merge commits require a one-based ReplayOptions::mainline parent; specifying a mainline for a non-merge is rejected.

Clean replay writes a one-parent commit. Cherry-pick preserves the original author and message while using the supplied committer; revert uses the supplied identity and generates Git's Revert "subject" message. no_commit updates the index and worktree without creating a commit. An empty replay is rejected unless allow_empty is enabled.

Conflicts write stages 1–3, conflict markers where applicable, CHERRY_PICK_HEAD or REVERT_HEAD, MERGE_MSG, and ORIG_HEAD. After resolution and add, call continue_replay. abort_replay restores the original tree and index. Continuation rejects unresolved stages or a HEAD which changed during the replay.

Git source comparisons

• sequencer.c:do_pick_commit defines cherry-pick/revert base direction, mainline selection, authorship, messages, and replay-head state.
• sequencer.c:sequencer_continue and sequencer_rollback define continuation and abort safety.
• merge-ort.c defines the shared three-way and conflict-stage behavior.

The implementation is independently structured in safe Rust and does not call Git, link to Git, or use gitoxide.