1bc7d61294
Adds: - docs/branching.md — beginner contributor guide - docs/adr/XXXX-...md — ADR (will be renamed with issue#) - .github/workflows/auto-backmerge.yml — disabled in Phase 1 - .github/workflows/pr-target-validator.yml — warn-only in Phase 1 - scripts/setup-branch-protection.sh — idempotent gh api script Modifies: - .github/workflows/branch-naming.yml — recognize 'next' - CONTRIBUTING.md — 'Where Do I Open My PR?' section Phase 1 is additive: nothing operational changes until Phase 2 flips auto-backmerge.yml's if:false→true, flips pr-target-validator.yml's WARN_ONLY→false, creates the next branch, and switches the default branch. See the ADR for the migration plan.
347 lines
16 KiB
Markdown
347 lines
16 KiB
Markdown
# Introduce `next` as a long-lived integration branch
|
|
|
|
- **Status:** Proposed
|
|
- **Date:** 2026-05-23
|
|
|
|
> **Filename note.** This ADR uses the placeholder (now resolved to `230`) per
|
|
> [CONTRIBUTING.md §Proposing an ADR](../../CONTRIBUTING.md). Before merging,
|
|
> open a `chore:` issue, replace `XXXX` with the assigned issue number, and
|
|
> rename the file accordingly.
|
|
|
|
## Context
|
|
|
|
Today every contributor branch — `feat/`, `fix/`, `chore/`, `docs/`,
|
|
`refactor/`, `test/`, `perf/`, `ci/`, `revert/` — is cut from `main` and PR'd
|
|
back to `main`. Release branches (`release/X.Y.0`) and hotfix branches
|
|
(`hotfix/X.Y.Z`) are also cut from `main`. As a result:
|
|
|
|
1. **`main` moves on every merge.** With ~315 unreleased changesets queued
|
|
and multiple PRs in flight at any time, `main` advances multiple times a
|
|
day.
|
|
2. **GitHub branch protection on `main` requires "branches up to date before
|
|
merging"** (the dominant pattern across mature OSS projects with linear
|
|
history). Every time another PR lands, every in-flight PR must rebase
|
|
before its own merge button enables.
|
|
3. **`release/X.Y.0` accumulates RC-cycle fixes that drift from `main`.**
|
|
When `finalize` opens the merge-back PR, the diff is large and
|
|
contributors who PR'd to `release/*` can't be sure their fix is also
|
|
queued for the next minor.
|
|
4. **`hotfix.yml` cherry-picks `fix:`/`chore:` commits from `main` since the
|
|
prior tag.** This works today only because every fix lands on `main`.
|
|
The pattern is fragile — any deviation (e.g. fix landing on `release/*`)
|
|
is invisible to the picker. v1.42.3 (#3621) shipped a half-state for
|
|
exactly this class of reason.
|
|
|
|
The maintainer's stated pain: *"every update doesn't mean the next pr needs
|
|
a rebase"* — i.e. the rebase treadmill from (2), driven by (1).
|
|
|
|
## Decision
|
|
|
|
Introduce **`next`** as a long-lived integration branch.
|
|
|
|
- All work that today targets `main` instead targets `next`, with the sole
|
|
exceptions of `release/X.Y.0` and `hotfix/X.Y.Z` branches, which still
|
|
merge to `main`.
|
|
- `next` is always at-or-ahead of `main`. Any push to `main` (release or
|
|
hotfix merge) triggers an automated back-merge PR `main → next` to keep
|
|
`next` aligned.
|
|
- Branch protection rules differ:
|
|
- **`main`** — strict: 2 reviewer approvals, all CI green, "require
|
|
branches up to date" **ON**, signed commits, restrict push to maintainers
|
|
via PR only.
|
|
- **`next`** — loose: 1 reviewer approval, all CI green, "require branches
|
|
up to date" **OFF**, auto-delete source branches.
|
|
- Default branch (in repo Settings) becomes `next`. `gh pr create` and the
|
|
GitHub web UI then default new PRs to the correct target without a flag.
|
|
|
|
### Where each branch type goes
|
|
|
|
| Branch prefix | Today's target | New target | Rationale |
|
|
|---|---|---|---|
|
|
| `feat/` | `main` | `next` | Features ship in minor releases |
|
|
| `fix/` | `main` | `next` | Regular fixes ship in minor (or get cherry-picked by hotfix.yml) |
|
|
| `chore/`, `docs/`, `refactor/`, `test/`, `perf/`, `ci/`, `revert/` | `main` | `next` | All same-flow as fixes |
|
|
| `fix/critical-*` | `main` | `main` | Production-down only, auto-back-merges to `next` |
|
|
| `release/X.Y.0` | `main` | `main` (cut from `next`) | Promoted to production on finalize |
|
|
| `hotfix/X.Y.Z` | `main` | `main` (cut from prior tag, cherry-picks from `next`) | Patch releases |
|
|
|
|
### Mechanical changes summary
|
|
|
|
| Component | Change |
|
|
|---|---|
|
|
| `release.yml` (`create`) | Branch from `next`, not `main` |
|
|
| `release.yml` (`finalize`) | Open merge-back PR to **both** `main` and `next` (was just `main`) |
|
|
| `hotfix.yml` (cherry-pick step) | Cherry-pick from `origin/next`, not `origin/main` |
|
|
| `hotfix.yml` (`finalize`) | Open merge-back PRs to both `main` and `next` (was just `main`) |
|
|
| `branch-naming.yml` | Add `next` to `alwaysValid` list |
|
|
| `auto-branch.yml` | Branch from `next` HEAD instead of `main` HEAD for issue-labeled branches |
|
|
| New `pr-target-validator.yml` | Block PRs targeting `main` from branches that aren't `release/*`, `hotfix/*`, or `fix/critical-*` |
|
|
| New `auto-backmerge.yml` | On push to `main`, open `main → next` PR |
|
|
| Repo settings | Default branch = `next`; squash-merge only on `next`; merge-commit on `main` (preserve tag context) |
|
|
| `scripts/setup-branch-protection.sh` | New: idempotent script to apply both branch protection rule sets via `gh api` |
|
|
|
|
## Consequences
|
|
|
|
### Positive
|
|
|
|
- **Rebase treadmill ends.** PRs targeting `next` are not gated on
|
|
"up-to-date before merge". Concurrent PRs to `next` merge in any order as
|
|
long as they don't conflict on the same lines.
|
|
- **`main` becomes a stable reference.** It changes only on release/hotfix
|
|
merges — a handful of times per week, not multiple times per day. CI on
|
|
`main` runs less; downstream consumers (linked CI, npm tag watchers) see
|
|
fewer transient states.
|
|
- **Hotfix cherry-pick base is unambiguous.** All `fix:`/`chore:` commits
|
|
candidate for a hotfix live on `next`. The cherry-pick filter (today
|
|
hardcoded against `origin/main`) becomes correct-by-construction once
|
|
retargeted to `origin/next`.
|
|
- **RC-only fixes flow back to `next` automatically.** Today a fix that
|
|
lands on `release/1.28.0` to unblock RC2 only makes it to `next`-equivalent
|
|
(i.e. `main`) when finalize back-merges. Under the new model finalize
|
|
back-merges to both `main` and `next`, so an RC fix is never accidentally
|
|
dropped from the next minor.
|
|
- **Default branch switch is one click.** Cost is low; setting takes effect
|
|
for every new PR and clone immediately.
|
|
|
|
### Negative
|
|
|
|
- **One more concept to teach contributors.** Mitigated by `docs/branching.md`
|
|
+ CONTRIBUTING update + PR-target validator that says "retarget to `next`"
|
|
with a one-line fix instruction.
|
|
- **Hotfix and release workflows need updates.** Patches are inlined below.
|
|
Both are reversible — if a patch causes pain, revert and re-target the
|
|
workflows back to `main`. No on-disk state migration required.
|
|
- **The auto-backmerge PR is a new background-noise source.** It opens
|
|
silently after each release/hotfix push to `main`. Mitigated by labeling
|
|
the PR `automation` and auto-merging if CI passes (configurable in
|
|
`auto-backmerge.yml`).
|
|
- **Existing 315-changeset queue.** Doesn't strictly block this change but
|
|
the next release will be a large one. Recommend cutting `1.28.0` from
|
|
`main` (current behavior, last time) before flipping the default branch
|
|
to `next` — see "Migration" below.
|
|
|
|
### Risks not worth the trade-off
|
|
|
|
We considered and rejected:
|
|
|
|
- **`develop` instead of `next`.** The git-flow nomenclature is established
|
|
but the gitflow model itself is heavier than this project needs (no
|
|
long-lived `release/*` branches per-major, no `support/*` for old majors).
|
|
`next` matches the existing npm dist-tag (`@next`) and is the convention
|
|
for Angular, Next.js, React Native, and others. Use the name that already
|
|
appears in `VERSIONING.md`.
|
|
- **Merge queue.** GitHub's merge queue (GA in 2023) addresses the same
|
|
pain by serializing merges and rebasing+testing automatically. Rejected
|
|
because (a) it doesn't address the parallel work-stream separation that a
|
|
`next` branch gives, (b) it still requires "branches up to date" which we
|
|
want to relax, and (c) the maintainer is a git beginner and merge queue's
|
|
failure modes (split commits, requeued PRs) are harder to debug than a
|
|
conventional model.
|
|
- **Pure trunk-based with feature flags.** Rejected because the project
|
|
publishes to npm and doesn't have a runtime feature-flag system. Feature
|
|
flags would be a larger separate investment.
|
|
|
|
## Migration
|
|
|
|
This is a phase-gated rollout. Each phase is reversible.
|
|
|
|
### Phase 0 — Decide
|
|
|
|
1. Open a `chore:` issue: "Introduce `next` integration branch". Get the
|
|
issue number. Rename this ADR file from `XXXX-` to `<issue#>-`.
|
|
2. Review this ADR. Decide on the merge-commit-vs-squash policy for `next`
|
|
(recommended: squash) and for `main` (recommended: merge commit on
|
|
release back-merges, to preserve the tag-commit relationship).
|
|
|
|
### Phase 1 — Additive infrastructure (no behavior change)
|
|
|
|
The following land on `main` (current model, one last time) before flipping:
|
|
|
|
- `docs/branching.md` (new)
|
|
- `docs/adr/<issue#>-introduce-next-integration-branch.md` (this file)
|
|
- `scripts/setup-branch-protection.sh` (new)
|
|
- `.github/workflows/auto-backmerge.yml` (new, disabled with
|
|
`if: false` until phase 2)
|
|
- `.github/workflows/pr-target-validator.yml` (new, in "warning only" mode)
|
|
- `.github/workflows/branch-naming.yml` (update: add `next` to `alwaysValid`)
|
|
- CONTRIBUTING.md update: "Where do I open my PR?" section
|
|
|
|
### Phase 2 — Flip
|
|
|
|
When the next release is ready to start its RC cycle:
|
|
|
|
1. Cut the current planned release (e.g. `1.28.0`) using `release.yml` as
|
|
today — this drains the 315-changeset queue from `main` cleanly.
|
|
2. After `v1.28.0` finalizes and back-merges to `main`, run:
|
|
```bash
|
|
git checkout main && git pull --ff-only
|
|
git checkout -b next && git push -u origin next
|
|
```
|
|
3. Apply branch protection: `bash scripts/setup-branch-protection.sh`.
|
|
4. Settings → Branches → change default branch to `next`.
|
|
5. Re-enable `auto-backmerge.yml` (remove the `if: false`).
|
|
6. Flip `pr-target-validator.yml` from warning-only to enforcing.
|
|
|
|
### Phase 3 — Retarget release/hotfix workflows
|
|
|
|
Apply these patches once `next` is established and the team has run at
|
|
least one feature PR through it.
|
|
|
|
**`release.yml` — branch from `next` (create step):**
|
|
|
|
```diff
|
|
@@ create:
|
|
- name: Create release branch
|
|
env:
|
|
BRANCH: ${{ needs.validate-version.outputs.branch }}
|
|
VERSION: ${{ inputs.version }}
|
|
IS_MAJOR: ${{ needs.validate-version.outputs.is_major }}
|
|
run: |
|
|
+ git fetch origin next:next || git fetch origin main:main
|
|
- git checkout -b "$BRANCH"
|
|
+ git checkout -b "$BRANCH" next 2>/dev/null || git checkout -b "$BRANCH" main
|
|
```
|
|
|
|
The `|| main` fallback is for the transition window where `next` may not
|
|
yet exist. After Phase 2 the fallback can be removed.
|
|
|
|
**`release.yml` — back-merge to both branches (finalize step):**
|
|
|
|
```diff
|
|
@@ Create PR to merge release back to main
|
|
- name: Create PR to merge release back to main
|
|
...
|
|
+ - name: Create PR to merge release back to next
|
|
+ if: ${{ !inputs.dry_run }}
|
|
+ continue-on-error: true
|
|
+ env:
|
|
+ GH_TOKEN: ${{ github.token }}
|
|
+ BRANCH: ${{ needs.validate-version.outputs.branch }}
|
|
+ VERSION: ${{ inputs.version }}
|
|
+ run: |
|
|
+ EXISTING_PR=$(gh pr list --base next --head "$BRANCH" --state open --json number --jq '.[0].number' 2>/dev/null || echo "")
|
|
+ if [ -n "$EXISTING_PR" ]; then
|
|
+ gh pr edit "$EXISTING_PR" \
|
|
+ --title "chore: merge release v${VERSION} to next" \
|
|
+ --body "Merge release branch back to next after v${VERSION} stable release (picks up RC-only fixes)." \
|
|
+ || echo "::warning::Could not update next merge-back PR. Open it manually."
|
|
+ else
|
|
+ gh pr create \
|
|
+ --base next \
|
|
+ --head "$BRANCH" \
|
|
+ --title "chore: merge release v${VERSION} to next" \
|
|
+ --body "Merge release branch back to next after v${VERSION} stable release (picks up RC-only fixes)." \
|
|
+ || echo "::warning::Could not create next merge-back PR. Open it manually."
|
|
+ fi
|
|
```
|
|
|
|
**`hotfix.yml` — cherry-pick from `next` (with `main` fallback):**
|
|
|
|
```diff
|
|
@@ Cherry-pick fix/chore commits from origin/main since base tag
|
|
- - name: Cherry-pick fix/chore commits from origin/main since base tag
|
|
+ - name: Cherry-pick fix/chore commits from origin/next since base tag
|
|
...
|
|
run: |
|
|
set -euo pipefail
|
|
- git fetch origin main:refs/remotes/origin/main
|
|
+ # Prefer next; fall back to main during the transition window or
|
|
+ # for production-down emergencies that landed directly on main.
|
|
+ if git ls-remote --exit-code origin next >/dev/null 2>&1; then
|
|
+ git fetch origin next:refs/remotes/origin/next
|
|
+ SOURCE="origin/next"
|
|
+ else
|
|
+ git fetch origin main:refs/remotes/origin/main
|
|
+ SOURCE="origin/main"
|
|
+ fi
|
|
|
|
- CANDIDATES=$(git cherry "$BASE_TAG" origin/main | awk '/^\+ / {print $2}')
|
|
+ CANDIDATES=$(git cherry "$BASE_TAG" "$SOURCE" | awk '/^\+ / {print $2}')
|
|
...
|
|
- ORDERED=$(git log --reverse --format='%H' "$BASE_TAG..origin/main" \
|
|
+ ORDERED=$(git log --reverse --format='%H' "$BASE_TAG..$SOURCE" \
|
|
| grep -F -f <(echo "$CANDIDATES") || true)
|
|
```
|
|
|
|
**`hotfix.yml` — back-merge to both branches (finalize step):**
|
|
|
|
```diff
|
|
@@ Create PR to merge hotfix back to main
|
|
- name: Create PR to merge hotfix back to main
|
|
...
|
|
+ - name: Create PR to merge hotfix back to next
|
|
+ if: ${{ !inputs.dry_run }}
|
|
+ env:
|
|
+ GH_TOKEN: ${{ github.token }}
|
|
+ BRANCH: ${{ needs.validate-version.outputs.branch }}
|
|
+ VERSION: ${{ inputs.version }}
|
|
+ run: |
|
|
+ EXISTING_PR=$(gh pr list --base next --head "$BRANCH" --state open --json number --jq '.[0].number')
|
|
+ if [ -n "$EXISTING_PR" ]; then
|
|
+ gh pr edit "$EXISTING_PR" \
|
|
+ --title "chore: merge hotfix v${VERSION} back to next" \
|
|
+ --body "Merge hotfix changes back to next after v${VERSION} release."
|
|
+ else
|
|
+ gh pr create \
|
|
+ --base next \
|
|
+ --head "$BRANCH" \
|
|
+ --title "chore: merge hotfix v${VERSION} back to next" \
|
|
+ --body "Merge hotfix changes back to next after v${VERSION} release."
|
|
+ fi
|
|
```
|
|
|
|
**`auto-branch.yml` — branch from `next`:**
|
|
|
|
```diff
|
|
- // Create branch from main HEAD
|
|
- const mainRef = await github.rest.git.getRef({
|
|
+ // Create branch from next HEAD (fall back to main if next missing)
|
|
+ let baseRef;
|
|
+ try {
|
|
+ baseRef = await github.rest.git.getRef({
|
|
owner: context.repo.owner,
|
|
repo: context.repo.repo,
|
|
- ref: 'heads/main',
|
|
- });
|
|
+ ref: 'heads/next',
|
|
+ });
|
|
+ } catch (e) {
|
|
+ if (e.status !== 404) throw e;
|
|
+ baseRef = await github.rest.git.getRef({
|
|
+ owner: context.repo.owner,
|
|
+ repo: context.repo.repo,
|
|
+ ref: 'heads/main',
|
|
+ });
|
|
+ }
|
|
|
|
await github.rest.git.createRef({
|
|
owner: context.repo.owner,
|
|
repo: context.repo.repo,
|
|
ref: `refs/heads/${branch}`,
|
|
- sha: mainRef.data.object.sha,
|
|
+ sha: baseRef.data.object.sha,
|
|
});
|
|
```
|
|
|
|
### Phase 4 — Cleanup
|
|
|
|
After 2-3 successful releases under the new model:
|
|
|
|
- Remove the `|| main` fallbacks from `release.yml` and `hotfix.yml`.
|
|
- Remove `develop` from `branch-naming.yml` `alwaysValid` (it was vestigial;
|
|
the project never used it).
|
|
- Drop warning-only mode from `pr-target-validator.yml`.
|
|
|
|
## References
|
|
|
|
- `docs/branching.md` — contributor-facing how-to-use-it guide
|
|
- `VERSIONING.md` — semver tiers and npm dist-tag mapping
|
|
- `.github/workflows/release.yml`, `.github/workflows/hotfix.yml` —
|
|
release/hotfix automation that this ADR adjusts
|
|
- `scripts/setup-branch-protection.sh` — bootstrap script for branch
|
|
protection rules
|
|
- [Angular branching model](https://github.com/angular/angular/wiki/Branching-Strategy)
|
|
— closest analogue (`main` + `<version>-next`)
|
|
- [Next.js release flow](https://github.com/vercel/next.js#contributing)
|
|
— uses `canary` as the integration branch with the same shape
|