GH PR
Overview
Create or update GitHub Pull Requests with the gh CLI using a detailed body template and strict same-branch rules.
Decision rules (must follow)
- Do not create or switch branches. Always use the current branch as the PR head.
- Check for an existing PR for the current head branch.
- gh pr list --head <head> --state all --json number,state,mergedAt,updatedAt,url,title,mergeCommit
- If no PR exists → create a new PR.
- If any PR exists and is NOT merged (
mergedAtis null) → push only and finish (do not create a new PR).
- This applies to OPEN or CLOSED (unmerged) PRs. - Only update title/body/labels if the user explicitly requests changes.
- If all PRs for the head are merged → check for post-merge commits (see below).
- If multiple PRs exist for the head → use the most recently updated PR for reporting, but the create vs push decision is based on
mergedAt.
Post-merge commit check (critical)
When all PRs for the head branch are merged, you must check whether there are new commits after the merge:
- Get the merge commit SHA of the most recent merged PR.
- Count commits after the merge:
git rev-list --count <merge_commit>..HEAD - Decision:
- If new commits exist → create a new PR (these changes are not in the base branch) - If no new commits → report "No changes since last merge" and finish (do not create an empty PR)
Why this matters
- Scenario A: PR merged → user makes local changes → pushes → changes are NOT in the merged PR
- Without this check, the changes would be lost or require manual intervention
- Scenario B: PR merged → user says "create PR" without new changes → would create empty/duplicate PR
- This check prevents unnecessary PR creation
Workflow (recommended)
- Confirm repo + branches
- Repo root: git rev-parse --show-toplevel - Current branch (head): git rev-parse --abbrev-ref HEAD - Base branch defaults to develop unless user specifies.
- Fetch latest remote state
- git fetch origin to ensure accurate comparison
- Check existing PR for head branch
- Use decision rules above to pick action. - Treat mergedAt as the source of truth for "merged".
- If all PRs are merged, perform post-merge commit check
- Get merge commit: gh pr list --head <head> --state merged --json mergeCommit -q '.[0].mergeCommit.oid' - Count new commits: git rev-list --count <merge_commit>..HEAD - If 0 → finish with message "No new changes since merge" - If >0 → proceed to create new PR
- Ensure the head branch is pushed
- If no upstream: git push -u origin <head> - Otherwise: git push
- Collect PR inputs (for new PR or explicit update)
- Title, Summary, Context, Changes, Testing, Risk/Impact, Deployment, Screenshots, Related Links, Notes - Optional: labels, reviewers, assignees, draft
- Build PR body from template
- Read references/pr-body-template.md and fill placeholders. - If info is missing, keep TODO markers and explicitly mention them in the response.
- Create or update the PR
- Create: gh pr create -B <base> -H <head> --title "<title>" --body-file <file> - Update (only if user asked): gh pr edit <number> --title "<title>" --body-file <file>
- Return PR URL
- gh pr view <number> --json url -q.url
Command snippets (bash)
head=$(git rev-parse --abbrev-ref HEAD)
base=develop
# Fetch latest remote state
git fetch origin
# Check existing PRs for the head branch
pr_json=$(gh pr list --head "$head" --state all --json number,state,mergedAt,mergeCommit)
pr_count=$(echo "$pr_json" | jq 'length')
unmerged_count=$(echo "$pr_json" | jq 'map(select(.mergedAt == null)) | length')
if [ "$pr_count" -eq 0 ]; then
action=create
elif [ "$unmerged_count" -gt 0 ]; then
action=push_only
else
# All PRs are merged - check for post-merge commits
merge_commit=$(echo "$pr_json" | jq -r 'sort_by(.mergedAt) | last | .mergeCommit.oid')
if [ -n "$merge_commit" ] && [ "$merge_commit" != "null" ]; then
new_commits=$(git rev-list --count "$merge_commit"..HEAD 2>/dev/null || echo "0")
if [ "$new_commits" -gt 0 ]; then
echo "Found $new_commits commit(s) after merge - creating new PR"
action=create
else
echo "No new commits since merge - nothing to do"
action=none
fi
else
# Fallback: check against base branch
new_commits=$(git rev-list --count "origin/$base"..HEAD 2>/dev/null || echo "0")
if [ "$new_commits" -gt 0 ]; then
action=create
else
action=none
fi
fi
fi
# Execute action
case "$action" in
create)
# Create PR body from template (edit as needed)
cat > /tmp/pr-body.md <<'BODY'
## Summary
- TODO (one-sentence outcome)
- TODO (user-visible change, if any)
## Context
- TODO (why this PR is needed)
- TODO (background, ticket, or incident link)
## Changes
- TODO (key changes, bullets)
- TODO (notable refactors or cleanup)
## Testing
- TODO (commands run)
- TODO (manual steps, if any)
## Risk / Impact
- TODO (areas impacted)
- TODO (rollback plan / mitigation)
## Deployment
- TODO (steps, flags, or "none")
## Screenshots
- TODO (UI changes only)
## Related Issues / Links
- TODO (issues, specs, docs)
## Checklist
- [ ] Tests added/updated
- [ ] Lint/format checked
- [ ] Docs updated
- [ ] Migration/backfill plan included (if needed)
- [ ] Monitoring/alerts updated (if needed)
## Notes
- TODO (optional)
BODY
git push -u origin "$head"
gh pr create -B "$base" -H "$head" --title "..." --body-file /tmp/pr-body.md
;;
push_only)
echo "Existing unmerged PR found - pushing changes only"
git push
gh pr list --head "$head" --state open --json url -q '.[0].url'
;;
none)
echo "No action needed - no new changes since last merge"
;;
esacReferences
references/pr-body-template.md: PR body template