Production Release Gating

Gating production deploys to real releases

By default, a push/merge to main deploys to production. With semantic-release you usually want the opposite: previews on feature branches, but production only on an actual release (a versioned chore(release): commit / a published GitHub Release).

There are three ways to enforce that. They have names, not letters, so you can pick one by name and record it (see "pick the flow" below):

Decision rule:

• Want to keep the platform's native git deploys with zero platform-specific scripting? → Promotion Branch (set the production branch, promote on release). Most portable; the recommended default for Vercel/Netlify/CF Pages.
• You own the deploy (GKE/self-hosted/any dispatchable target, or you want CI to drive a platform CLI)? → Release-Triggered Deploy.
• Locked into a platform's push-deploy and can't add a branch/promotion? → Build-Skip Gate (the ignore script) as the fallback.

Works with both per-merge and pooled releases — pick the flow, then record it

All three gates are orthogonal to release cadence: they key on the chore(release): commit + tag + published GitHub Release, which is produced identically whether you release on every merge (semantic-release-automation) or in batches (pooled-release). So the same gate works under either workflow — you don't re-pick it if you later switch cadence.

Because the gate is a lasting repo convention (and double-gating is a real footgun — see Gotchas), when wiring this up for a project:

1. Confirm the flow with the user — don't assume. Which pattern (Release-Triggered Deploy / Promotion Branch / Build-Skip Gate)? Which branch is production? Which platform? Per-merge or pooled release trigger?
2. Record the decision so it's durable and visible. Write a short line in the repo's AGENTS.md (and/or the deploy workflow header), e.g. "Prod gating: Promotion Branch — production branch production, platform Vercel, pooled release." Future agents and humans then follow the same flow instead of re-deriving — or silently contradicting — it.

Release-Triggered Deploy — deploy on a published Release

semantic-release creates a GitHub Release; this workflow fires on on: release with types: [published] and rolls out github.event.release.tag_name, then writes the deploy status back onto the Release body. Plain pushes to main deploy nothing.

• The deploy step is whatever command you control — that's the point of "you deploy." The template shows a GKE/kubectl rollout, but the same job can call a platform CLI (vercel deploy --prod --prebuilt, netlify deploy --prod), hit a deploy hook (curl "$DEPLOY_HOOK_URL"), wrangler deploy, flyctl deploy, etc. The gate (fire only on the published Release) is identical; only the rollout command differs.
• vs the platform's own git deploy: use this when you want CI to own the prod deploy. If you'd rather keep the platform's native git integration and just gate which branch it watches, use Promotion Branch instead.
• ⚠️ If the platform has native git auto-deploy (Vercel/Netlify), DISABLE its default-branch prod deploy — or you double-ship. This CI deploy is in addition to the platform's automatic push deploy, so without this the platform still ships prod on every merge to main. Two ways:
  • Vercel — vercel.json: { "git": { "deploymentEnabled": { "main": false } } } stops Vercel deploying main (other branches still get previews; CI's --prebuilt --prod is unaffected). Or Project → Settings → Git → turn off the production branch's auto-deploy.
  • Netlify — netlify.toml [context.production] command = "exit 0" (or "Stop auto publishing" / lock the production deploy) so pushes to the prod branch don't auto-build; CLI deploys still publish.
  • Or reuse the Build-Skip Gate inverted: point vercel-ignore.sh at this app but make main always skip (CI owns prod) while feature branches still build previews — the same script, the opposite verdict on main.
• Token caveat: a Release created with the built-in GITHUB_TOKEN will not trigger on: release. Have semantic-release run with a PAT/bot GH_TOKEN so its Release fires this workflow. (See semantic-release-automation → token notes.)
• Pre-releases don't deploy: the deploy job is guarded with if: ${{ !github.event.release.prerelease }}, so semantic-release next/beta channel releases (published with prerelease: true) are skipped — only a stable Release ships to prod.
• Tag shape is validated: the deploy step refuses a tag_name that isn't SemVer (v?MAJOR.MINOR.PATCH), so a stray/mis-shaped tag can't roll out. Adjust the regex to your scheme.
• Ancestry is enforced (parity with Promotion Branch): before deploying, the step fetches the default branch and runs git merge-base --is-ancestor "$SHA" origin/<default>, refusing a tag whose commit isn't on the default branch — so a tag published on off-main/unrelated code (anyone with contents: write can push v9.9.9) can't roll that code out to prod. The branch is auto-resolved from github.event.repository.default_branch; override DEFAULT_BRANCH only if you cut releases from a branch other than the repo default.
• concurrency uses two global groups, not per-tag: stable releases share prod-release and prereleases get a separate prod-release-prerelease group, both with cancel-in-progress: false, so deploys never run concurrently and an in-progress rollout is never half-killed. The split matters because concurrency is joined before the job-level prerelease if — a shared group would let a skipped prerelease run evict a queued stable deploy from the single pending slot. Caveat: GitHub keeps only one pending run per group, so even among stable releases a newer one can evict an older queued one — if every tag must deploy, add an external queue/lock rather than relying on concurrency alone.

Promotion Branch — staging main, fast-forward production

The most portable gate: keep the platform's native git deploys, but point its Production Branch at a dedicated production branch instead of main. Now main is a preview/staging branch (deploys on every merge, but not to prod), and prod ships only when production advances. templates/promote-to-production.yml fires on the published Release and fast-forwards production to the released commit; the platform's webhook then deploys it. No platform CLI, no ignore script — just a branch update, so it works on Vercel, Netlify, Cloudflare Pages, anything with a configurable production branch.

• Setup is one-time: create production off main, set it as the platform's Production Branch, and run semantic-release with a PAT/bot GH_TOKEN (same token caveat as Release-Triggered Deploy — the built-in token's Release won't fire on: release).
• production only ever fast-forwards from main, so it stays an ancestor of the release commit and the promotion push is always a clean fast-forward. A rejected (non-fast-forward) push is a real divergence to inspect — never --force past it.
• Ancestry is enforced, not assumed: before pushing, the workflow fetches the default branch and runs git merge-base --is-ancestor "$SHA" origin/<default>, refusing to promote a tag whose commit isn't on the default branch. This stops an off-main or unrelated tag from shipping arbitrary code to prod. It fetches into the same ref it validates (origin <branch>:refs/remotes/origin/<branch>). The branch is auto-resolved from github.event.repository.default_branch, so a non-main default needs no edit — override DEFAULT_BRANCH only if you cut releases from a branch other than the repo default.
• Pairs naturally with pooled-release: semantic-release runs on main (button/cron) and tags; this promotes the tag to prod. Merges to main keep shipping staging; prod ships on the train.

Build-Skip Gate — Vercel Ignored Build Step

Vercel runs an Ignored Build Step before building; its exit code decides: exit 1 = build, exit 0 = skip (note the inversion). Wire templates/vercel-ignore.sh via vercel.json ("ignoreCommand": "bash ../../scripts/vercel-ignore.sh") or Project Settings → Git → Ignored Build Step. Logic:

• Feature branch → build (preview deployment). This is the whole point of previews; don't gate them.
• main, release commit (chore(release): … / chore(scope): release …) or [deploy] marker → build (production).
• main, anything else → skip.
• [skip-deploy] on any branch → skip.

The release regexes require a stable SemVer version anchored on the right (X.Y.Z at end-of-string or before whitespace), so a prerelease commit like chore(release): 1.2.3-next.1 (semantic-release next/beta channels cut from main) does not match and does not ship to prod — matching the prerelease-guarded Release-Triggered/Promotion gates. The script also fails closed: if git can't read the message, an empty message falls through to the main skip rather than erroring (a non-zero exit reads as build on Vercel).

Monorepo: Vercel's "Skipping Unaffected Projects" is layer 1 (Turborepo graph); this script is layer 2. A per-app script also builds when a dependency package releases — add a clause like ^chore\((shared-lib|design-system)\):\ release\ v?[0-9]+\.[0-9]+\.[0-9]+ (shown commented in the template, with the same anchored-version requirement so non-release chore(shared-lib): … commits don't build) so an app redeploys when its shared lib version bumps.

Gotchas

• Exit codes are inverted in the Build-Skip Gate / Vercel ignore step (0 = skip). The single most common mistake.
• Preview vs prod: keep feature-branch previews ungated; only main is strict. Gating previews defeats the workflow.
• Release-Triggered Deploy needs a non-default token on the release side, or the Release won't trigger the deploy (silent no-op).
• Release-Triggered Deploy on Vercel/Netlify double-deploys unless you disable native prod auto-deploy. The platform ships main on every merge and CI ships on the Release. Turn off the platform's default-branch deploy (Vercel git.deploymentEnabled.main: false; Netlify stop auto-publishing) so only CI ships prod. (Not an issue on GKE/self-hosted — nothing auto-deploys there.)
• Don't gate in two places at once. Pick one pattern per app; doubling up (e.g. a production branch and an ignore script) makes "why didn't it deploy?" much harder to debug.
• Promotion Branch: don't leave main as the platform's production branch. The whole gate is moving the Production Branch to production; forget that step and every merge to main still ships to prod.
• [skip ci] in the release commit (the monorepo semantic-release flavor) means push-triggered workflows won't see it — which is exactly why Release-Triggered Deploy keys on the Release event, not the push.
• Pre-releases must not reach prod. Both the deploy and promote jobs gate on if: ${{ !github.event.release.prerelease }}; without it, a next/beta Release would ship to production. Keep the guard if you adapt these. The Build-Skip Gate has no release event to read prerelease from, so it enforces the same rule via its regex — the version is anchored on the right (X.Y.Z at end/whitespace) so a chore(release): 1.2.3-next.1 prerelease commit doesn't match; don't loosen that anchor or prereleases start shipping prod.
• Supply chain — pin actions to commit SHAs for a hardened posture. These workflows run with contents: write, and @v7/@v9 are mutable tags — even first-party actions/* tags can be re-pointed — so for strict supply-chain safety pin every uses: (including actions/checkout/actions/github-script, not just third-party like pnpm/action-setup) to a full commit SHA with a # vX.Y.Z comment, and let Dependabot bump them. The templates ship readable major tags as the convenient default; tighten to SHAs where the risk warrants.

See also

• semantic-release-automation — produces the release commit / GitHub Release this gate keys on.
• pooled-release — batched releases; the same gate ships prod on the train, not on merges.
• conventional-commits — why the release commit looks like chore(release): ….

Sources

• Generalised from production repos: a production app (Release-Triggered Deploy — on: release / types: [published] dispatches a GKE deploy and annotates the Release with status) and a production monorepo (Build-Skip Gate — per-app vercel.json ignoreCommand → vercel-ignore-<app>.sh with branch/release/dependency-aware exit codes).
• Vercel Ignored Build Step: https://vercel.com/docs/projects/overview#ignored-build-step
• Promotion Branch builds on each platform's configurable production branch primitive: Vercel (Project → Settings → Git → Production Branch) and Netlify (Site configuration → Build & deploy → Branches → Production branch). Promoting via a fast-forward of production is a generalisation of that native feature, so the gate stays platform-agnostic.