Cherry-picking: when it fits and what it costs the history

What it is

git cherry-pick <commit> applies the change a commit introduces on top of the current branch and records a new commit. The documentation requires a clean working tree, stops on conflicts with CHERRY_PICK_HEAD set until --continue, --skip or --abort, and offers -x to append a line "(cherry picked from commit ...)" to the message. Picking a merge commit needs -m <parent-number> to say which parent is the mainline. -n / --no-commit applies several picks into the index before one commit.

Why it matters

The new commit has the same patch but a different ID and parent. Git compares commits by ancestry, so a later merge of the source branch does not know that the change is already present: an identical change on both sides usually merges cleanly, but any difference (a conflict resolved during the pick, a later edit of the same lines) becomes a conflict, and the history keeps two commits for one change either way. Every pick therefore adds a small, permanent cost: history that must be reconciled by patch content rather than by ancestry. git log --cherry-pick --left-right A...B exists precisely to omit commits that introduce the same change on the other side, as the git-log documentation describes.

How to apply

• Backporting a fix: commit the fix on the oldest supported branch and merge upward, or pick it downward with -x so the origin stays traceable. The documentation recommends -x for picks between public branches and advises against it for private ones.
• Salvaging one good commit from a branch that will be discarded: pick it, then delete the branch so no duplicate lineage remains.
• Wanting a whole branch: merge or rebase it. Picking every commit of a branch produces a second lineage of the same changes that a later merge cannot recognise as already integrated.
• Hotfix released from a release branch: pick into main immediately, before the two diverge further.
• Keep picked commits small and self-contained; a pick of half a refactor conflicts on the other half later.

Pitfalls

A pick of a commit that depends on earlier, unpicked commits compiles by luck or not at all. Conflict resolution during a pick is not recorded anywhere except the new commit. Bisecting a branch made of picks points at the copy, not at the original discussion, unless -x lines are present. Repeated picks between long-lived branches are a sign that the branching model, not the tool, needs changing.