push-to-forked-pr

push-to-forked-pr

The whole point of this skill: origin is usually the upstream, but the PR's head is on someone else's fork. Pushing to origin updates the upstream's branch, not the PR. You have to push to the fork.

GitHub allows this in two situations:

1. You are the fork owner — straightforward, you own that branch.
2. You are an upstream maintainer and the PR has maintainerCanModify: true (the "Allow edits from maintainers" checkbox the PR author leaves on by default). GitHub then lets the upstream's auth push to the fork branch.

If neither holds, abort and tell the user only the fork owner can push.

---

Procedure

1. Read the PR's head metadata

PR_NUMBER=<N>
gh pr view "$PR_NUMBER" --json state,headRefName,headRefOid,headRepository,headRepositoryOwner,maintainerCanModify,url

Capture:

• state — bail if not "OPEN".
• headRepository.nameWithOwner → the fork (e.g. someone/Repo).
• headRepositoryOwner.login → the fork owner.
• headRefName → the branch on the fork (usually matches local).
• headRefOid → the PR's current head SHA. Your local HEAD must be a descendant.
• maintainerCanModify → must be true if you are not the fork owner.

If headRepository.nameWithOwner matches the upstream's nameWithOwner, this PR is internal:

HEAD_BRANCH=$(gh pr view "$PR_NUMBER" --json headRefName --jq .headRefName)
HEAD_REF_OID=$(gh pr view "$PR_NUMBER" --json headRefOid --jq .headRefOid)
git merge-base --is-ancestor "$HEAD_REF_OID" HEAD && echo ok || echo NOT-DESCENDANT   # abort if NOT-DESCENDANT
git push origin "HEAD:${HEAD_BRANCH}"

Exit the skill once this push lands — do not continue to the fork-push steps below.

2. Confirm you can actually push

gh auth status                        # who am I?
git remote get-url origin             # fetch URL — confirm origin is the UPSTREAM, not the fork
git remote get-url --push origin      # push URL — can differ from the fetch URL if `pushurl` is configured

For the internal-PR path above, compare the push URL (not just the fetch URL) against the expected upstream nameWithOwner before relying on git push origin — a configured pushurl can silently redirect the push to a different destination than the fetch URL suggests.

You may push to the fork branch iff the active gh user is:

• the fork owner, or
• a writer on the upstream and maintainerCanModify == true.

Otherwise stop. Tell the user the PR doesn't allow maintainer edits.

3. Sanity-check the local branch

git branch --show-current
git rev-parse HEAD
git merge-base --is-ancestor <headRefOid> HEAD && echo ok || echo NOT-DESCENDANT

• If headRefName differs from the current local branch, that's fine — you'll push with an explicit refspec local:headRefName in step 6.
• If local HEAD is not a descendant of headRefOid, stop. Either you're on the wrong branch, or someone else has pushed to the PR since you forked from it. Do not force-push without explicit user permission.

4. Verify commit author identity before committing

git config user.email

If it is empty, hostname-shaped ([email protected], *@*.tail*.ts.net, etc.), or otherwise not a real email tied to a GitHub account, the commit will appear "unverified" on GitHub and won't link to a profile. Override per-commit:

git -c user.name="<Name>"  -c user.email="<email>"  commit -F /tmp/commit-msg.txt

To correct an already-made commit before push:

git -c user.name="..." -c user.email="..." commit --amend --reset-author -C HEAD --no-edit

Prefer the user's documented identity (e.g. from CLAUDE.md or earlier in the session) over the local git config when the local config is clearly machine-generated.

5. Run the repo's full verification suite — before pushing

The user almost always asks for this explicitly. In this repo (see CLAUDE.md for the authoritative list):

npm run format:check                        # tracked files only; local .worktrees/ noise is not yours to fix
npm run test:server                         # backend touched
npm run test:client                         # frontend, wiki i18n, screen snapshots
npm run mcp:typecheck && npm run mcp:build  # mcp/ touched
npm --prefix mcp test                       # mcp unit suite
npm run build                               # production client build
bash .claude/skills/file-headers/scripts/check-headers.sh

Per-package extras when those areas are touched:

npm --prefix desktop run build && npm --prefix desktop test
node scripts/validate-agent-extensions.js

Stop on the first red. Report which check failed and do not push.

6. Stage, commit, push to the fork (not origin)

Exclude session-local noise (.claude/settings.local.json is harness state, not work) and never stage blindly:

git status                          # review exactly what changed
git add <path1> <path2> ...         # stage only the files for this PR's change — never `git add -A`
git status                          # confirm the staged diff matches intent (and excludes .claude/settings.local.json) before committing

Commit with a real body (use -F for multi-paragraph messages), ending with the Co-Authored-By trailer your harness requires — copy it verbatim from the harness instructions rather than from this file, so the model name never goes stale.

Then push to the fork. Add a one-off remote so it's clear in git remote -v and the destination URL doesn't end up in the user's shell history:

FORK_REPO=$(gh pr view "$PR_NUMBER" --json headRepository --jq '.headRepository.nameWithOwner')
HEAD_BRANCH=$(gh pr view "$PR_NUMBER" --json headRefName   --jq .headRefName)
LOCAL_BRANCH=$(git branch --show-current)

if [ -z "$LOCAL_BRANCH" ]; then
  echo "Detached HEAD — refusing to push (source ref would be empty and delete ${HEAD_BRANCH} on the fork)." >&2
  exit 1
fi

git remote add "pr${PR_NUMBER}-fork" "https://github.com/${FORK_REPO}.git"
git push "pr${PR_NUMBER}-fork" "HEAD:${HEAD_BRANCH}"    # push HEAD itself, not "$LOCAL_BRANCH" — safe even if the local branch name differs

gh configures git's credential helper, so HTTPS pushes pick up the right token automatically. Don't rewrite to SSH unless asked.

7. Verify the push landed on the PR

LOCAL_HEAD=$(git rev-parse HEAD)
PR_HEAD=$(gh pr view "$PR_NUMBER" --json headRefOid --jq .headRefOid)
[ "$LOCAL_HEAD" = "$PR_HEAD" ] && echo "PR updated ✓" || echo "MISMATCH — push went somewhere else"

Report the new HEAD SHA, the PR URL, and the diff stat back to the user.

---

Common failure modes

Symptom	Cause	Fix
Permission denied on push	Authenticated as the wrong user, or maintainerCanModify: false and you are not the fork owner	Abort. Only the fork owner can push to the branch.
! [rejected] non-fast-forward	Someone else pushed to the PR since you started	git fetch "pr${PR_NUMBER}-fork" "${HEAD_BRANCH}", then rebase or merge. Never force-push someone else's PR branch without explicit permission.
Push succeeds, but PR head SHA doesn't update	You pushed to a branch with a different name on the fork	Re-check headRefName and use explicit refspec LOCAL:HEAD_BRANCH.
Commit shows "unverified" on the PR	Author email isn't tied to a verified GitHub account	Amend with the user's real identity (step 4) and push again (fast-forward, not force).
Could not resolve host	Network or proxy issue	Surface the error. Don't blanket-retry.

---

Hard rules

• Never push to origin when origin is the upstream and the PR head is a fork. Always verify with git remote -v and gh pr view.
• Never create a new branch. The user pushed because they want this PR updated; a new branch defeats that.
• Never force-push to a fork PR branch without explicit user permission. The fork owner will lose any commits they had locally.
• Always run the repo's tests/builds first. A fork-PR push triggers CI on the fork and surfaces on the upstream's PR view — pushing red code is doubly visible.
• Always exclude .claude/settings.local.json unless the user explicitly says to include it. It's harness session state, not the work.
• Never stage with git add -A. Stage explicit paths for the requested change so unrelated files or local secrets can't ride along.