omnigraph/docs/dev/branch-protection.md
Andrew Altshuler c7365bf8ef
ci(codeowners): un-trap required checks, auto-render, generate owner tables (#142)
The CODEOWNERS required checks blocked every PR — the real root cause was a
name mismatch, compounded by a path filter:

- branch-protection.json required the contexts `CODEOWNERS / drift` and
  `CODEOWNERS / noedit` (the GitHub UI "workflow / job-id" display form), but
  the jobs report check-run names from their `name:` fields — "CODEOWNERS
  matches source" / "CODEOWNERS not hand-edited". The required contexts
  therefore never matched any reported check and sat permanently pending.
- The workflow was also path-filtered to CODEOWNERS files, so it didn't even
  run for most PRs.

Net effect: with both required checks unsatisfiable, every PR could only land
via admin override (e.g. #140).

Fixes:
- A: drop the `paths:` filter so the workflow runs on every PR and both
  required contexts always report.
- name fix: point branch-protection.json at the actual job names verbatim, and
  add a doc note that the contexts must equal the job `name:` values.
- B: the `drift` job now re-renders and, on same-repo PRs, auto-commits the
  regenerated artifacts back to the branch (mirrors the openapi.json job in
  ci.yml); forks / manual runs strict-check instead. Contributors no longer
  run the script by hand.
- D: render-codeowners.py also generates a "who owns what" path->owners +
  roles table spliced into docs/dev/codeowners.md between markers, so the
  human-readable view never drifts. Idempotent; CODEOWNERS output unchanged.
- docs: correct the stale `enforce_admins: true` line (JSON and live are
  false).

NOTE: the branch-protection.json change only takes effect after an admin runs
`./scripts/apply-branch-protection.sh` (deliberate manual step, per
docs/dev/branch-protection.md). Until then `main` still requires the old
mismatched contexts, so this PR itself needs an admin-override merge — the last
one that should be necessary.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-06 18:09:47 +03:00

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4.9 KiB
Markdown

# Branch protection on `main`
`main` is gated by a declarative branch-protection policy. The source of truth is `.github/branch-protection.json`; the apply mechanism is `scripts/apply-branch-protection.sh`. Re-running the script with a changed JSON is idempotent.
This page explains what the policy says and how to change it.
## Current policy
| Setting | Value | Why |
|---|---|---|
| **Required status checks (strict)** | `Classify Changes`, `Check AGENTS.md Links`, `Test Workspace`, `Test omnigraph-server --features aws`, `CODEOWNERS matches source`, `CODEOWNERS not hand-edited` | Every PR must pass workspace tests, AGENTS.md link integrity, and the CODEOWNERS hygiene checks. The two CODEOWNERS contexts must equal the job `name:` values in `.github/workflows/codeowners.yml` **verbatim** — a context naming a job that never reports (the old `CODEOWNERS / drift` used the job *id*, and the job was path-filtered) leaves every PR permanently pending and forces admin overrides. `strict: true` requires the branch to be up-to-date with `main` before merge. |
| **Required approving reviews** | `1` | At least one reviewer. With a 2-person team, going higher would block all merges when one person is unavailable. |
| **Require code-owner reviews** | `true` | The reviewer must be a code owner per `.github/CODEOWNERS`. This is what makes the codeowners chassis enforced. |
| **Dismiss stale reviews on new commits** | `true` | A push after approval invalidates the prior review. Prevents the "approve, then sneak in unreviewed changes" pattern. |
| **Require linear history** | `true` | No merge commits — squash or rebase only. Matches recent practice. |
| **Disallow force pushes** | `true` | No history rewrites on `main`. |
| **Disallow branch deletions** | `true` | `main` cannot be deleted. |
| **Required conversation resolution** | `true` | All review comment threads must be resolved before merge. |
| **Enforce on admins** | `false` | Admins can override the gates (`enforce_admins: false` in the JSON). This is the intended escape hatch for the 2-person team; tightening to `true` is tracked under hardening below. |
| **Required signed commits** | not yet | Not enabled. Would lock out maintainers until everyone enrolls GPG/SSH commit signing. Tracked as a follow-up. |
## How to apply
Run from the repository root:
```bash
./scripts/apply-branch-protection.sh
```
The script reads `.github/branch-protection.json`, strips the human-readable `_comment` field (the GitHub API rejects unknown keys), and PUTs to `repos/ModernRelay/omnigraph/branches/main/protection`.
Requires `gh` authenticated with a token that has admin permissions on the repository.
To preview without applying:
```bash
DRY_RUN=1 ./scripts/apply-branch-protection.sh
```
## How to change the policy
1. Edit `.github/branch-protection.json`.
2. Open a PR. The JSON change goes through normal review.
3. After the PR merges, an admin runs `./scripts/apply-branch-protection.sh` to push the new policy to GitHub.
The script is **not run automatically** by CI. Branch-protection changes are admin actions that should be applied deliberately — a CI-driven automatic apply would mean any merged PR could rewrite protection rules, which defeats the purpose. The script's existence makes the apply reproducible; the admin's manual invocation is the audit point.
## How to read the current GitHub state
```bash
gh api repos/ModernRelay/omnigraph/branches/main/protection
```
Outputs the live policy. Compare against `.github/branch-protection.json` to detect drift.
## Why declared as code
- **Audit trail**: `git log .github/branch-protection.json` shows every change with a reviewable diff and a merge commit.
- **Disaster recovery**: if branch protection is accidentally removed or weakened via the UI, the JSON is the canonical recovery point.
- **Consistency**: pairs with `.github/codeowners-roles.yml` (the CODEOWNERS source of truth). Repository policy lives in the repository.
## What this gates
After branch protection is applied, every PR targeting `main` must:
1. Pass all listed status checks.
2. Be up-to-date with `main` (rebase or merge-from-main).
3. Have at least one approving review from a code owner for the touched paths.
4. Have all review conversations resolved.
5. Be squash- or rebase-merged (no merge commits).
Even repository admins are subject to these rules.
## Subsequent hardening (not in this PR)
The branch-protection policy is the foundation. Future hardening adds:
- **Required signed commits** (`required_signatures: true`) — once maintainers enroll GPG/SSH signing.
- **Tag protection** for `v*` tags via `repos/.../tags/protection`.
- **Required reviewers from specific teams** for high-leverage paths (e.g., `docs/dev/invariants.md`) via CODEOWNERS tier expansion + the N-unique-approvers CI workaround.
- **More required CI checks**: `cargo deny`, `cargo audit`, `cargo fmt --check`, `cargo clippy -D warnings`, CodeQL, secret scanning, schema-lint (MR-946).
See the hardening playbook for the full plan.