Cherry-pick a commit

A fast way to cherry-pick (backport) a commit from one branch onto another — usually a fix from the development branch to a release/servicing branch. It keeps the happy path quick and the unhappy path safe: the usual failure modes are branching off a stale local copy of the target, silently resolving a conflict the wrong way, or forgetting to reference the original PR. A conflict should stop you and surface the problem, never turn into a guess.

What you need before starting

Figure these two things out first (from the user's request, then by inspecting the repo):

1. Source — which commit(s) to cherry-pick. Common phrasings:
   • "the latest commit on dev" → the tip of origin/<dev-branch> (after fetching). Do not trust the local branch; resolve it against origin.
   • a PR number (e.g. "#7576") → the squash-merge commit for that PR on the source branch.
   • an explicit SHA or range.
2. Target — the branch to cherry-pick onto (e.g. "7.9.x"). Users abbreviate release branches; map the shorthand to the real ref by listing remote branches (a name like 7.9.x usually means release/7.9.x or release-7.9.x). Confirm the ref actually exists on origin before continuing.

If either is genuinely ambiguous, ask. Otherwise proceed — this is meant to be low-friction.

The workflow

Run these steps in order. Interpret output at each step; don't blindly chain commands, because a bad early step (dirty tree, wrong target) makes everything after it wrong.

1. Preflight

git status --porcelain            # must be empty — a dirty tree makes cherry-pick/abort unsafe
git fetch origin --prune          # get the true tips of source and target
git rev-parse --abbrev-ref HEAD   # remember where you started, to return here later

If the working tree is dirty, stop and tell the user (offer to stash). Fetching matters: release branches and dev move independently, and a local release/* is frequently behind origin.

2. Resolve the real refs

git rev-parse --short origin/<dev-branch>        # -> the source SHA, if "latest on dev"
git branch -r | grep -i <target-shorthand>       # confirm the target ref name on origin
git branch -r --contains <source-sha> | grep <target>   # is it ALREADY on the target?

If the commit is already contained in the target branch, don't cherry-pick — report that it's already there. Cherry-picking an already-present change produces an empty or redundant commit.

3. Create the working branch off the remote target

Name it using the repository's branch convention. Many repos (including NuGet.Client) use dev-<github-handle>-<topic>; check the repo's instructions/AGENTS.md if unsure, and get the handle from gh api user --jq .login. Make the topic descriptive of the backport, e.g. cherrypick-<pr-or-sha>-<target>.

git checkout -b dev-<handle>-cherrypick-<pr-or-sha>-<target> origin/<target-ref>

Branching off origin/<target-ref> (not the local copy) is the single most important correctness step — it guarantees you build on the real head of the release branch.

4. Cherry-pick

Use -x so the new commit records "(cherry picked from commit …)". Preserving the original commit message (including the (#NNNN) PR suffix) is what lets a reviewer follow the change back to its origin — this is an explicit expectation for release-branch commits in some repos, so keep it.

git cherry-pick -x <source-sha>

For a range, use git cherry-pick -x <from>^..<to>.

5. Branch on the result

• Success (exit 0, clean apply): continue to step 6.

• Conflict / failure (non-zero exit, or git status shows unmerged paths): do not resolve it yourself unless the user asked you to. Capture which files conflicted, then undo cleanly and report:

  git cherry-pick --abort
  git checkout <original-branch>
  git branch -D dev-<handle>-cherrypick-<pr-or-sha>-<target>   # remove the aborted branch

  Then STOP and report back using the failure template below. A conflict means the target branch has diverged in the touched code; that needs a human decision, and silently picking a side is how backports introduce regressions.

6. Finish the PR (success path only)

Only reformat if you had to resolve conflicts by hand — a clean cherry-pick reproduces already-formatted, already-reviewed content byte-for-byte, so running a full format is wasted work and can create spurious diffs. If the repo mandates formatting and you did edit files, run its formatter now.

Delegate the push and PR creation to the repo's create-pr skill (.copilot/skills/create-pr) rather than re-implementing them here — that skill owns the branch push, PR template, draft default, gh invocation, and error handling, and keeping one source of truth means backport PRs stay consistent with every other PR in the repo. Hand it these backport-specific parameters:

• Base branch: the target branch (<target-ref>) — override its default of dev.
• Title: the original commit subject, unchanged, so the (#NNNN) link is preserved.
• Body: the backport content described below.
• Backport PRs don't need review and merge once the build is green (see docs/workflow.md), so create it ready (non-draft) unless the user says otherwise.

Then report the resulting PR URL.

PR description (what to feed the create-pr skill)

The create-pr skill builds the body from the PR template; your job is to give it backport-specific content that makes it obvious this is a port, not a new change:

• State that it's a cherry-pick of the original PR/commit onto the target branch, and link the original PR (#NNNN).
• Reuse the original PR's linked issue, keeping the same prefix it used (Fixes:/Progress:).
• Tick checklist items that genuinely apply (e.g. tests are "added" if the original commit carried them; they came along with the pick).

Failure report template

When a cherry-pick fails, after aborting and cleaning up, report like this so the user can decide what to do:

Cherry-pick FAILED — conflicts, nothing pushed.

- Source: <sha> "<subject>" (from <source-branch>/#<pr>)
- Target: <target-ref>
- Conflicting files:
    - path/one.cs
    - path/two.cs

The target branch has diverged in these files. I aborted the cherry-pick and deleted the temporary
branch, so your tree is back on <original-branch> and unchanged. Want me to retry and resolve the
conflicts, or would you prefer to handle it manually?

Notes and edge cases

• Never rewrite history or force-push on shared branches.
• One commit per PR is the usual release-branch norm (so a single revert is clean). Only batch multiple commits into one PR if the user asks.
• Merge commits need -m 1 to pick the mainline parent; prefer picking the underlying squash commit instead when possible.
• Empty result ("The previous cherry-pick is now empty"): the change is already present — run git cherry-pick --skip/--abort as appropriate and report it's already in the target.