molecule-core/.github/workflows/check-migration-collisions.yml
Hongming Wang ea8ff626a9 ci: hard gate against migration version collisions (#2341)
Two PRs targeting staging can each add a migration with the same
numeric prefix (e.g. 044_*.up.sql). Each passes CI independently.
They collide at merge time. Worst case: second migration silently
doesn't apply and prod schema drifts from what the code expects.

Caught manually 2026-04-30 during PR #2276 rebase: 044_runtime_image_pins
collided with 044_platform_inbound_secret from RFC #2312. This workflow
makes that detection automatic at PR-open time.

How it works:
  scripts/ops/check_migration_collisions.py runs on every PR that
  touches workspace-server/migrations/**. For each new/modified
  migration filename, extracts the numeric prefix and checks:

  1. Does the base branch already have a DIFFERENT migration file with
     the same prefix? (PR branched off an old base, base advanced and
     another PR landed the same number — needs rebase.)

  2. Is another OPEN PR (not this one) also adding a migration with
     the same prefix? (Race-window collision — both pass CI separately,
     would collide at merge time.)

Either case → exit 1 with a clear ::error:: message naming the
conflicting PR(s) so the author knows what to renumber.

Implementation notes:
  - Uses git ls-tree (not working-tree walk) so it works against any
    base ref without checkout.
  - Uses gh pr diff --name-only per open PR, bounded by `gh pr list
    --limit 100`. ~30s worst case for a busy repo, <5s normally.
  - --diff-filter=AM picks up Added or Modified — renaming a migration
    in place is also flagged (intentional; renaming migrations isn't
    safe).
  - Same filename in both PR and base = no collision (PR is editing
    in-place, fine).

Tests:
  scripts/ops/test_check_migration_collisions.py — 9 cases on the
  regex classifier (the load-bearing piece). End-to-end git/gh path
  is exercised by running the workflow against real PRs.

Hard-gates Tier 1 item 1 (#2341). Cheapest, cleanest gate. Catches
one specific class of merge-time foot-gun automatically.

Refs hard-gates discussion 2026-04-30. Tier 1 of 4 (others tracked
in #2342, #2343, #2344).
2026-04-29 21:42:42 -07:00

52 lines
1.9 KiB
YAML

name: Check migration collisions
# Hard gate (#2341): fails a PR that adds a migration prefix already
# claimed by the base branch or another open PR. Caught manually 2026-04-30
# during PR #2276 rebase: 044_runtime_image_pins collided with
# 044_platform_inbound_secret from RFC #2312. This workflow makes that
# check automatic.
#
# Trigger model: pull_request only — there's no value running this on
# pushes to staging or main (those are post-merge; the gate must fire
# pre-merge to be useful). Path filter scopes to PRs that actually touch
# migrations.
on:
pull_request:
types: [opened, synchronize, reopened]
paths:
- 'workspace-server/migrations/**'
- 'scripts/ops/check_migration_collisions.py'
- '.github/workflows/check-migration-collisions.yml'
permissions:
contents: read
# gh pr list/diff need read access to other PRs
pull-requests: read
jobs:
check:
name: Migration version collision check
runs-on: ubuntu-latest
timeout-minutes: 5
steps:
- uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
with:
# Need history to diff against base ref
fetch-depth: 0
- name: Detect collisions
env:
PR_NUMBER: ${{ github.event.pull_request.number }}
BASE_REF: origin/${{ github.event.pull_request.base.ref }}
HEAD_REF: ${{ github.event.pull_request.head.sha }}
GITHUB_REPOSITORY: ${{ github.repository }}
# gh CLI uses GH_TOKEN from env
GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
run: |
# Make sure base ref is fetched (checkout@v4 with fetch-depth=0
# fetches history but not necessarily named refs in the form we
# expect; explicit fetch is cheap insurance).
git fetch origin "${{ github.event.pull_request.base.ref }}" --depth=1 || true
python3 scripts/ops/check_migration_collisions.py