--- name: git-trunk-branch-and-pr-automation description: "Trunk-based Git workflow with enforced branch naming and squash-merge PR titles. Use when setting up or standardising a branch/PR workflow, naming branches (feature/ fix/ hotfix/ and AI-agent prefixes claude/ cursor/ codex/ copilot/ codegen-bot/ dependabot/), configuring squash-only merges where the PR title becomes the commit and the body is the concatenated commits, making the PR title a valid Conventional Commit, adding GitHub Actions that validate branch names or auto-normalise PR titles, fixing a PR-title bot that loops, or deciding trunk vs release branches. Covers the GitHub repo settings, the validation/normalisation workflows, and how it feeds semantic-release." metadata: author: stealth-engine co-author: wiiiimm version: "1.2.0" --- # Trunk-based branches + squash-PR automation A trunk-based workflow where every change is a short-lived branch off `main`, merged via **squash** with a **Conventional Commit PR title**. That title becomes the single commit on `main` that [semantic-release](../semantic-release-automation/SKILL.md) reads — so naming and title hygiene aren't cosmetic, they drive the release. Templates: [`templates/`](./templates) — branch-name validation, the PR-title normaliser workflow, and the shared `normalize-pr-title.js`. ## The model - **Trunk-based:** branch off `main`, keep PRs small, merge frequently; `main` stays releasable. Don't use long-lived `develop`/release branches unless you must stabilise a release while trunk moves on, or support multiple live versions. - **Branch naming:** `feature/`, `fix/`, `hotfix/` — plus **AI-agent prefixes** `claude/ cursor/ codex/ copilot/ codegen-bot/ dependabot/` for agent- and bot-authored branches. Validated by [`branch-name-check.yml`](./templates/branch-name-check.yml). ## Squash merge: the PR title *is* the commit Configure the repo so a merge collapses to one clean, semantic commit: - **GitHub → Settings → General → Pull Requests:** enable **Squash merging only** (turn off merge commits and rebase). Set **"Default commit message" → "Pull request title and commit details"** — GitHub then uses the **PR title as the squash subject** (it appends `(#)`, which doesn't affect Conventional Commit parsing) and **concatenates the PR's commit messages into the body**. - So: the **title** must be a valid Conventional Commit (it's what semantic-release analyses → version + changelog); the **body** (the concatenated commits) preserves the detailed history. - Keep a PR to **one logical change** (in a monorepo, one package) so the single squashed commit maps cleanly to one type+scope. See [`conventional-commits`](../conventional-commits/SKILL.md). ## PR-title automation [`pr-title-manager.yml`](./templates/pr-title-manager.yml) + [`normalize-pr-title.js`](./templates/normalize-pr-title.js) keep the title valid: - On open/reopen/synchronize it normalises the title to Conventional Commits (lowercasing the type, or synthesising `: ` from the PR's commits / branch prefix when the title isn't conventional). - A correct title is left untouched; the **`skip-title-automation` label** opts out of the auto-rewrite for the rare edge case (still validated — see [Opting out](#opting-out-of-the-auto-rewrite) below). - It posts a **sticky comment** explaining the squash convention. - Install the script at `.github/scripts/normalize-pr-title.js`; the workflow `sparse-checkout`s the `.github/scripts` directory to load it. Pair it with `branch-name-check.yml`, and in **branch protection** require both checks (plus your release/CI checks) before a PR can merge. ### Opting out of the auto-rewrite There are two cases — and the **first covers almost everyone**: 1. **Just write a valid Conventional Commit title.** The normaliser only rewrites a title that *isn't* already conventional; a correct title (`feat: add x`, `fix(api): …`) is left **completely untouched**. There's nothing to "skip" — this is the intended path. 2. **Add the `skip-title-automation` label** (create it once in the repo) only for the rare case where the title isn't conventional *yet* and you don't want the bot auto-editing it / posting its comment while you sort it out (e.g. mid-review). The label suppresses the **auto-rewrite + sticky comment** — but **not validation**: the required check still **fails** until the title is a valid Conventional Commit (or a `type!:` breaking commit is reflected by a `!`). So the label changes *who* fixes the title (you, not the bot), never *whether* it must be valid before merge. The opt-out is a **label, not a string in the title**, on purpose: the PR title becomes the squash commit semantic-release reads, so any marker left in the title would land in the release commit and silently produce **no release**. The label is also ignored on the fork/bot validate path (it never edits there, so there's nothing to suppress). ## Gotchas - **Three modes — and don't loop on your own edits.** The template classifies each PR: `skip` only for **`github-actions[bot]`** (its *own* title edits — the workflow listens for `edited` to re-validate human changes, and skipping its own identity stops the loop). With the **default `GITHUB_TOKEN` this is belt-and-braces** — GitHub deliberately doesn't retrigger workflows on events its own token caused, so the bot's edit wouldn't re-fire anyway; the skip only *matters* if you swap in a PAT or GitHub App token (whose edits **do** retrigger), so keep it. `validate` for **forks and other bots like dependabot** (read-only/untrusted → title is checked but never auto-edited); `normalize` for same-repo human PRs (run the script + fix the title). Don't blanket-skip all bots — a non-self bot with a non-conventional title would otherwise merge unchecked. - **Agent/bot branch prefixes don't infer a type.** `claude/ cursor/ codex/ …` are valid branch names, but the normaliser derives the type from the PR's **commits** (which should be conventional), not the prefix — falling back to `chore` only if neither title nor commits are conventional. Keep agent commits conventional so the bump is right. - **Fork / bot PRs are validate-only.** `pull_request` from a fork gets a **read-only** token *and* an attacker-controlled checkout, so the template never checks out or runs the (PR-modifiable) script for them — it validates the title inline via the API (read-only) and **fails** if it isn't a valid Conventional Commit (any type, including non-releasing `docs:`/`chore:`), or if a `type!:`-style breaking commit isn't reflected by a `!` in the title. Same-repo human branches (the norm for this trunk-based workflow) are the only ones auto-edited. Configure dependabot with a conventional `commit-message.prefix` so its titles pass. - **Squash settings are per-repo and easy to miss** — if "Default commit message" is left as "Default" (the first commit's message) instead of **"Pull request title and commit details"**, your carefully-named PR title is ignored at merge. - **The opt-out suppresses the rewrite, not the validation.** The `skip-title-automation` label stops the auto-edit + sticky comment but the title is **still checked** (the required check fails until it's a valid Conventional Commit) — full details in [Opting out](#opting-out-of-the-auto-rewrite) above. A green check always means a releasable title; the label can't bypass that. ## See also - [`conventional-commits`](../conventional-commits/SKILL.md) — the format the title must follow. - [`semantic-release-automation`](../semantic-release-automation/SKILL.md) — consumes the squashed commit to cut the release. - [`production-release-gating`](../production-release-gating/SKILL.md) — deploys only the resulting release. - [`resolve-merge-conflicts`](../resolve-merge-conflicts/SKILL.md) — resolving the conflicts/behind-base updates a branch hits before it can squash-merge. ## Sources - Generalised from a production app's `branch-name-check.yml` (the `feature|fix|hotfix|codegen-bot|copilot|codex|cursor|claude|dependabot` prefix set) and `pr-title-manager.yml` + `normalize-pr-title.js` (title normalisation, the `skip-title-automation` label opt-out, bot-cascade guard, sticky comment). - GitHub squash-merge commit-message options: