Fix: the PR triage bot reads only the newest run of each check

changelog/2026-11-01-pr-triage-newest-run.md

@@ -0,0 +1 @@
+- PR triage bot: it now reads only the newest run of each check, so a failed or cancelled earlier run beside its green rerun no longer marks a pull request `needs-work`. The bot stays switched off.

scripts/pr-triage.mjs

@@ -24,6 +24,18 @@ export function decide({ red, labels, labeledAt, headDate, now, queued }) {
   return actions
 }
 
+/** The newest run of each check name: a failed or cancelled earlier run beside its green rerun (each rerun
+ * of a workflow is a new check suite, which `filter=latest` does not merge) must not count. Newest = started
+ * last (a run not started yet counts as newest), then the higher id. */
+export function newestRuns(runs) {
+  const newest = new Map(), started = run => Date.parse(run.started_at ?? '') || Infinity
+  for (const run of runs) {
+    const kept = newest.get(run.name)
+    if (!kept || started(run) > started(kept) || (started(run) === started(kept) && run.id > kept.id)) newest.set(run.name, run)
+  }
+  return [...newest.values()]
+}
+
 /** Contributors without a published module get one module PR reviewed at a time: every newer one waits. */
 export function queuedPulls(pulls, registered) {
   const waiting = new Set(), byAuthor = new Map()
@@ -58,7 +70,7 @@ async function main() {
   const queued = queuedPulls(pulls, registered), now = Date.now()
   for (const { pr } of pulls) {
     const runs = await pages(api, '/commits/' + pr.head.sha + '/check-runs?filter=latest', 'check_runs')
-    const red = runs.some(run => ['failure', 'timed_out', 'startup_failure'].includes(run.conclusion))
+    const red = newestRuns(runs).some(run => ['failure', 'timed_out', 'startup_failure'].includes(run.conclusion))
     const labeled = (await pages(api, '/issues/' + pr.number + '/events')).filter(event => event.event === 'labeled' && event.label?.name === NEEDS_WORK).at(-1)
     const actions = decide({ red, labels: pr.labels.map(label => label.name), labeledAt: labeled?.created_at, headDate: (await api('/commits/' + pr.head.sha)).commit.committer.date, now, queued: queued.has(pr.number) })
     for (const action of actions) {

scripts/pr-triage.test.mjs

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest'
-import { CLOSE_AFTER_DAYS, NEEDS_WORK, ONE_AT_A_TIME, decide, queuedPulls } from './pr-triage.mjs'
+import { CLOSE_AFTER_DAYS, NEEDS_WORK, ONE_AT_A_TIME, decide, newestRuns, queuedPulls } from './pr-triage.mjs'
 
 const day = 86400000, now = Date.parse('2026-10-25T12:00:00Z'), ago = days => new Date(now - days * day).toISOString()
 const base = { red: false, labels: [], labeledAt: undefined, headDate: ago(30), now, queued: false }
@@ -17,6 +17,14 @@ describe('PR triage policy', () => {
     expect(decide({ ...red, labeledAt: ago(CLOSE_AFTER_DAYS), headDate: ago(2) })).toEqual([])
     expect(decide({ ...red, labeledAt: undefined })).toEqual([])
   })
+  it('reads only the newest run of each check, so a green rerun replaces an earlier failure', () => {
+    const run = (id, name, conclusion, started_at) => ({ id, name, conclusion, started_at })
+    const runs = [run(1, 'module-pr-ok', 'failure', ago(1)), run(2, 'module-pr-ok', 'success', ago(0.5)), run(3, 'module-contract', 'cancelled', ago(1)), run(4, 'flag', 'success', ago(1))]
+    expect(newestRuns(runs).map(r => r.id).sort()).toEqual([2, 3, 4])
+    expect(newestRuns([run(5, 'x', 'failure', ago(1)), run(6, 'x', 'success', ago(1))]).map(r => r.id)).toEqual([6])
+    expect(newestRuns([run(7, 'x', 'failure', ago(1)), run(8, 'x', null, null)]).map(r => r.id)).toEqual([8])
+    expect(newestRuns([run(9, 'x', 'success', ago(1)), run(10, 'x', 'failure', ago(0.5))]).map(r => r.id)).toEqual([10])
+  })
   it('queues every newer module PR from a contributor without a published module', () => {
     const pulls = [{ number: 12, author: 'new', module: true }, { number: 10, author: 'new', module: true }, { number: 11, author: 'new', module: false }, { number: 13, author: 'known', module: true }, { number: 14, author: 'known', module: true }]
     expect([...queuedPulls(pulls, new Set(['known']))]).toEqual([12])