test(sweep): pin the no-catch-up recovery of delayed reviewers after missed schedule runs

__tests__/bundle/blunderbussDelayOutage.test.ts

@@ -0,0 +1,123 @@
+import type { FakeGithub } from './fakeGithub'
+import { Buffer } from 'node:buffer'
+import { afterAll, afterEach, beforeAll, describe, expect, it, vi } from 'vitest'
+
+import labelFileContents from '../fixtures/labels/labelFileContentsResp.json'
+import pullReqListPulls from '../fixtures/pullReq/pullReqListPulls.json'
+import { blobSha } from '../utils/ownersData'
+import { start } from './fakeGithub'
+import { repo, token } from './helpers'
+import { runBundle } from './runBundle'
+
+vi.setConfig({ testTimeout: 30_000 })
+
+// The recovery expectation of the delayed-reviewers sweep after the schedule
+// missed runs for longer than `sweep.lookback` (src/cronJobs/sweep.ts, `sweep`
+// → `recentlyUpdatedPulls` with `due.from`): the list stops at
+// `now − delay − lookback`, so a pull request nobody touched since its review
+// clock expired before that instant is neither listed, read nor requested.
+// There is no unbounded catch-up; a longer `sweep.lookback` (capped at 24h) is
+// what widens the window.
+describe('dist/index.js delayed blunderbuss after missed schedule runs', () => {
+  let gh: FakeGithub
+  const owners = { OWNERS: 'reviewers:\n- bob\n' }
+
+  beforeAll(async () => {
+    gh = await start()
+  })
+  afterEach(() => gh.reset())
+  afterAll(() => gh.close())
+
+  function ago(minutes: number) {
+    return new Date(Date.now() - minutes * 60_000).toISOString()
+  }
+
+  function pull(number: number, minutesAgo: number) {
+    return {
+      ...structuredClone(pullReqListPulls[0]),
+      number,
+      created_at: ago(minutesAgo),
+      updated_at: ago(minutesAgo),
+      labels: [],
+      requested_reviewers: [],
+      requested_teams: [],
+      assignees: [],
+      draft: false,
+      user: { login: 'Codertocat' },
+      base: { ref: 'master', sha: 'basesha' },
+      head: { sha: `sha${number}`, repo: { full_name: 'Codertocat/Hello-World' } },
+    }
+  }
+
+  // #1 opened 90 minutes ago sits inside the default due window [now − 2h, now − 1h];
+  // #2 opened 2.5 hours ago fell out of it while no sweep ran, and nobody touched it since
+  const pulls = [pull(1, 90), pull(2, 150)]
+
+  function serve(config: string) {
+    const file = structuredClone(labelFileContents)
+    file.content = Buffer.from(config).toString('base64')
+    gh.route('GET', '/repos/Codertocat/.project/contents/prow.yaml', { status: 200, body: file })
+    gh.route('GET', new RegExp(`^${repo}/pulls\\?`), { status: 200, body: pulls })
+    for (const pr of pulls) {
+      gh.route('GET', `${repo}/pulls/${pr.number}`, { status: 200, body: pr })
+      gh.route('GET', `${repo}/pulls/${pr.number}/files`, { status: 200, body: [{ filename: 'x.go', status: 'modified' }] })
+      gh.route('GET', `${repo}/issues/${pr.number}/timeline`, { status: 200, body: [] })
+      gh.route('GET', `${repo}/pulls/${pr.number}/reviews`, { status: 200, body: [] })
+      gh.route('POST', `${repo}/pulls/${pr.number}/requested_reviewers`, { status: 201, body: {} })
+      // a candidate inside the plain window runs every sweep step, not only the delayed reviewers
+      gh.route('GET', `${repo}/issues/${pr.number}`, { status: 200, body: { labels: [] } })
+      gh.route('GET', `${repo}/issues/${pr.number}/comments`, { status: 200, body: [] })
+      gh.route('POST', `${repo}/issues/${pr.number}/comments`, { status: 201, body: {} })
+    }
+    gh.route('GET', `${repo}/branches/master`, { status: 200, body: { name: 'master', commit: { sha: 'basesha' } } })
+    const tree = Object.keys(owners).map(path => ({ path, type: 'blob', sha: blobSha(path) }))
+    gh.route('GET', `${repo}/git/trees/master`, { status: 200, body: { sha: 'master', truncated: false, tree } })
+    gh.route('GET', `${repo}/git/trees/basesha`, { status: 200, body: { sha: 'basesha', truncated: false, tree } })
+    for (const [path, contents] of Object.entries(owners)) {
+      gh.route('GET', `${repo}/git/blobs/${blobSha(path)}`, { status: 200, body: { encoding: 'base64', content: Buffer.from(contents).toString('base64') } })
+    }
+    gh.route('GET', `${repo}/labels`, { status: 200, body: [{ name: 'approved' }, { name: 'lgtm' }] })
+  }
+
+  function runSweep() {
+    return runBundle({ eventName: 'schedule', payload: {}, inputs: { ...token, jobs: 'sweep' }, apiUrl: gh.url })
+  }
+
+  function requested() {
+    return gh.requestsMatching('POST', /\/requested_reviewers$/).map(r => r.path).sort()
+  }
+
+  function timelineReads() {
+    return gh.requestsMatching('GET', /\/timeline\?per_page=100$/).map(r => r.path).sort()
+  }
+
+  it('does not catch up a pull request whose review clock expired before now − delay − lookback: not listed, read or requested', async () => {
+    serve('blunderbuss:\n  delay: 1h\n')
+
+    const result = await runSweep()
+
+    expect(result.status, result.stdout).toBe(0)
+    expect(result.errors).toEqual([])
+    expect(result.stdout).toContain('sweep: 0 candidates updated since')
+    expect(result.stdout).toContain('sweep: 1 more checked for delayed reviewers')
+    expect(requested()).toEqual([`${repo}/pulls/1/requested_reviewers`])
+    expect(timelineReads()).toEqual([`${repo}/issues/1/timeline?per_page=100`])
+    // one list page, nothing else about #2: the sweep never asks after it
+    expect(gh.requestsMatching('GET', /\/pulls\?/).map(r => r.path)).toEqual([`${repo}/pulls?state=open&sort=updated&direction=desc&per_page=100&page=1`])
+    expect(gh.requests.filter(r => /\/(?:pulls|issues)\/2(?:\/|$|\?)/.test(r.path))).toEqual([])
+  })
+
+  it('a longer sweep.lookback is what recovers it: the window reaches back to it and it gets reviewers', async () => {
+    serve('blunderbuss:\n  delay: 1h\nsweep:\n  lookback: 2h\n')
+
+    const result = await runSweep()
+
+    expect(result.status, result.stdout).toBe(0)
+    expect(result.errors).toEqual([])
+    // with the plain window now [now − 2h, now], #1 is an ordinary candidate and #2 the delayed-only one
+    expect(result.stdout).toContain('sweep: 1 candidate updated since')
+    expect(result.stdout).toContain('sweep: 1 more checked for delayed reviewers')
+    expect(requested()).toEqual([`${repo}/pulls/1/requested_reviewers`, `${repo}/pulls/2/requested_reviewers`])
+    expect(timelineReads()).toEqual([`${repo}/issues/1/timeline?per_page=100`, `${repo}/issues/2/timeline?per_page=100`])
+  })
+})

__tests__/cronJobTest/sweepDelayOutage.test.ts

@@ -0,0 +1,149 @@
+import { Buffer } from 'node:buffer'
+import * as core from '@actions/core'
+import { http } from 'msw'
+import { setupServer } from 'msw/node'
+import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { sweep } from '../../src/cronJobs/sweep'
+import { resetOwnersCaches } from '../../src/utils/owners'
+import labelFileContents from '../fixtures/labels/labelFileContentsResp.json'
+import pullReqOpenedEvent from '../fixtures/pullReq/pullReqOpenedEvent.json'
+import * as utils from '../testUtils'
+import { blobSha, branchHandler } from '../utils/ownersFixtures'
+
+const server = setupServer()
+beforeAll(() => server.listen(utils.failOnUnhandledRequest))
+afterEach(() => server.resetHandlers())
+afterAll(() => server.close())
+
+const repo = `${utils.api}/repos/Codertocat/Hello-World`
+const now = new Date('2026-09-16T12:00:00Z')
+
+function ago(minutes: number): string {
+  return new Date(now.getTime() - minutes * 60_000).toISOString()
+}
+
+function json(body: unknown, status = 200) {
+  return new Response(JSON.stringify(body), { status, headers: { 'Content-Type': 'application/json' } })
+}
+
+function prowYaml(text: string) {
+  const file = structuredClone(labelFileContents)
+  file.content = Buffer.from(text).toString('base64')
+  return http.get(utils.contentsUrl('.github/prow.yaml'), utils.mockResponse(200, file))
+}
+
+function pull(number: number, minutesAgo: number) {
+  return {
+    number,
+    state: 'open',
+    locked: false,
+    draft: false,
+    merged: false,
+    mergeable: true,
+    mergeable_state: 'clean',
+    labels: [],
+    created_at: ago(minutesAgo),
+    updated_at: ago(minutesAgo),
+    requested_reviewers: [],
+    requested_teams: [],
+    assignees: [],
+    user: { login: 'some-author' },
+    head: { sha: `sha${number}` },
+    base: { ref: 'master', sha: 'basesha' },
+  }
+}
+
+// The recovery expectation of the delayed-reviewers sweep (src/cronJobs/sweep.ts,
+// `sweep` → `recentlyUpdatedPulls` with `due.from`) after the schedule missed runs
+// for longer than `sweep.lookback`: the list stops at `now − delay − lookback`, so
+// a pull request nobody touched since its review clock expired before that instant
+// is neither listed, read nor requested, however due it is. There is no unbounded
+// catch-up; a longer `sweep.lookback` (capped at 24h) is what widens the window.
+describe('sweep with blunderbuss.delay after missed schedule runs', () => {
+  const owners = { OWNERS: 'approvers:\n- alice\nreviewers:\n- carol\n' }
+  let context: utils.MockContext
+  let calls: string[]
+
+  function recordCall({ request }: { request: Request }) {
+    const url = new URL(request.url)
+    calls.push(`${request.method} ${url.pathname}${url.search}`)
+  }
+
+  beforeEach(() => {
+    utils.setupJobsEnv('sweep')
+    vi.useFakeTimers({ now, toFake: ['Date'] })
+    resetOwnersCaches()
+    context = new utils.MockContext(pullReqOpenedEvent)
+    context.eventName = 'schedule'
+    calls = []
+    server.events.on('request:start', recordCall)
+  })
+
+  afterEach(() => {
+    server.events.removeListener('request:start', recordCall)
+    vi.useRealTimers()
+  })
+
+  // #1 opened 90 minutes ago sits inside the default due window [now − 2h, now − 1h];
+  // #2 opened 2.5 hours ago fell out of it while no sweep ran, and nobody touched it since
+  const pulls = [pull(1, 90), pull(2, 150)]
+
+  function serve(config: string) {
+    const tree = Object.keys(owners).map(path => ({ path, type: 'blob', sha: blobSha(path) }))
+    const requested: number[] = []
+    const timelineReads: number[] = []
+    server.use(
+      prowYaml(config),
+      ...utils.noOrgOrRepoConfigExcept(),
+      utils.defaultBranchTree(Object.keys(owners)),
+      branchHandler('basesha'),
+      http.get(`${repo}/git/trees/basesha`, utils.mockResponse(200, { sha: 'basesha', truncated: false, tree })),
+      ...Object.entries(owners).map(([path, contents]) => http.get(`${repo}/git/blobs/${blobSha(path)}`, utils.mockResponse(200, { encoding: 'base64', content: Buffer.from(contents).toString('base64') }))),
+      http.get(`${repo}/pulls`, utils.mockResponse(200, pulls)),
+      http.get(`${repo}/pulls/:number`, ({ params }) => json(pulls.find(pr => pr.number === Number(params.number)))),
+      http.get(`${repo}/pulls/:number/files`, utils.mockResponse(200, [{ filename: 'x.go', status: 'modified' }])),
+      http.get(`${repo}/issues/:number/timeline`, ({ params }) => {
+        timelineReads.push(Number(params.number))
+        return json([])
+      }),
+      http.get(`${repo}/pulls/:number/reviews`, utils.mockResponse(200, [])),
+      // a candidate inside the plain window runs every sweep step, not only the delayed reviewers
+      http.get(`${repo}/issues/:number`, utils.mockResponse(200, { labels: [] })),
+      http.get(`${repo}/issues/:number/comments`, utils.mockResponse(200, [])),
+      http.post(`${repo}/issues/:number/comments`, utils.mockResponse(201, {})),
+      utils.repoHasLabels(['approved', 'lgtm']),
+      http.post(`${repo}/pulls/:number/requested_reviewers`, ({ params }) => {
+        requested.push(Number(params.number))
+        return json({}, 201)
+      }),
+    )
+    return { requested, timelineReads }
+  }
+
+  it('does not catch up a pull request whose review clock expired before now − delay − lookback: not listed, read or requested', async () => {
+    const { requested, timelineReads } = serve('blunderbuss:\n  delay: 1h\n')
+    const info = vi.spyOn(core, 'info')
+
+    await expect(sweep(context)).resolves.toEqual({ candidates: [], merged: [], enqueued: [], failures: [] })
+
+    expect(requested).toEqual([1])
+    expect(timelineReads).toEqual([1])
+    expect(info).toHaveBeenCalledWith(`sweep: 1 more checked for delayed reviewers, updated since ${ago(120)}`)
+    // one list page, nothing else about #2: the sweep never asks after it
+    expect(calls.filter(call => call.includes('/pulls?'))).toEqual([`GET /repos/Codertocat/Hello-World/pulls?state=open&sort=updated&direction=desc&per_page=100&page=1`])
+    expect(calls.filter(call => /\/(?:pulls|issues)\/2(?:\/|$|\?)/.test(call))).toEqual([])
+  })
+
+  it('a longer sweep.lookback is what recovers it: the window reaches back to it and it gets reviewers', async () => {
+    const { requested, timelineReads } = serve('blunderbuss:\n  delay: 1h\nsweep:\n  lookback: 2h\n')
+    const info = vi.spyOn(core, 'info')
+
+    // with the plain window now [now − 2h, now], #1 is an ordinary candidate and #2 the delayed-only one
+    await expect(sweep(context)).resolves.toEqual({ candidates: [1], merged: [], enqueued: [], failures: [] })
+
+    expect([...requested].sort()).toEqual([1, 2])
+    expect([...timelineReads].sort()).toEqual([1, 2])
+    expect(info).toHaveBeenCalledWith(`sweep: 1 more checked for delayed reviewers, updated since ${ago(180)}`)
+  })
+})

docs/configuration.md

@@ -338,7 +338,11 @@ that nobody has been asked to review yet. The clock starts at `opened`, or at th
 sweep's list reaches back the extra `delay`, so a pull request nobody touched since it opened is
 still found; those older pull requests get this step only. Install the sweep job even under
 `pull_request_target`; its other steps are idempotent. A request lands up to one sweep interval
-after it is due, plus GitHub's scheduling delay. `/auto-cc` is never delayed.
+after it is due, plus GitHub's scheduling delay. The sweep does not catch up any further back:
+when the schedule misses runs for longer than `lookback`, a pull request whose review clock
+expired before `now − delay − lookback` without a sweep seeing it is never requested by this
+step. Size `lookback` (capped at 24h) to the longest outage to ride out, or request reviewers by
+hand or with `/auto-cc`. `/auto-cc` is never delayed.
 
 ```yaml
 blunderbuss: