fix(orchestration): compare stale-dispatch timestamps with julianday (#8514)

Co-authored-by: Orca <help@stably.ai>

src/main/runtime/orchestration/db.test.ts

@@ -6,6 +6,20 @@ import Database from '../../sqlite/sync-database'
 import { OrchestrationDb } from './db'
 import type { MessageType } from './db'
 
+// Overwrites the datetime('now')-seeded timestamps with explicit fixture values
+// so stale-detection assertions stay deterministic (no wall clock).
+function setDispatchTimes(
+  d: OrchestrationDb,
+  id: string,
+  dispatchedAt: string,
+  heartbeatAt: string | null = null
+): void {
+  const sqlite = (d as unknown as { db: Database.Database }).db
+  sqlite
+    .prepare('UPDATE dispatch_contexts SET dispatched_at = ?, last_heartbeat_at = ? WHERE id = ?')
+    .run(dispatchedAt, heartbeatAt, id)
+}
+
 describe('OrchestrationDb', () => {
   let db: OrchestrationDb | undefined
 
@@ -696,6 +710,67 @@ describe('OrchestrationDb', () => {
       expect(stale.map((s) => s.id)).toEqual([ctxB.id])
     })
 
+    // Regression for #8452: dispatched_at / last_heartbeat_at are written by
+    // datetime('now') (space-format, e.g. "2026-07-12 12:00:00") while the
+    // threshold is ISO ("...T11:55:00.000Z"). Raw TEXT ordering ranks the space
+    // (0x20) below the 'T' (0x54) at index 10, flagging fresh same-date rows.
+    it('getStaleDispatches ignores fresh SQLite space-format timestamps (#8452)', () => {
+      const d = createDb()
+
+      // Fresh worker: dispatched 12:00, heartbeat 12:05 (space-format), both
+      // after the 11:55 threshold → NOT stale.
+      const fresh = d.createDispatchContext(d.createTask({ spec: 'fresh' }).id, 'term_fresh')
+      setDispatchTimes(d, fresh.id, '2026-07-12 12:00:00', '2026-07-12 12:05:00')
+
+      // Legacy ISO-format fresh row (mixed-format table) stays fresh too.
+      const legacy = d.createDispatchContext(d.createTask({ spec: 'legacy' }).id, 'term_legacy')
+      setDispatchTimes(d, legacy.id, '2026-07-12T12:00:00.000Z', '2026-07-12T12:05:00.000Z')
+
+      // Genuinely hung: dispatched + heartbeated at 10:00, ~2h before threshold.
+      const hung = d.createDispatchContext(d.createTask({ spec: 'hung' }).id, 'term_hung')
+      setDispatchTimes(d, hung.id, '2026-07-12 10:00:00', '2026-07-12 10:00:00')
+
+      const stale = d.getStaleDispatches('2026-07-12T11:55:00.000Z')
+      expect(stale.map((s) => s.id)).toEqual([hung.id])
+    })
+
+    it('getStaleDispatches keeps a just-dispatched space-format row in the grace window (#8452)', () => {
+      const d = createDb()
+
+      // Space-format dispatched_at one minute after the threshold, no heartbeat
+      // yet → still inside the grace window, must not be flagged.
+      const ctx = d.createDispatchContext(d.createTask({ spec: 'x' }).id, 'term_x')
+      setDispatchTimes(d, ctx.id, '2026-07-12 12:00:00')
+
+      const stale = d.getStaleDispatches('2026-07-12T11:59:00.000Z')
+      expect(stale).toEqual([])
+    })
+
+    // Same-UTC-date midnight threshold: keeps the buggy space-vs-'T' compare in
+    // play so this guards the fix at a day boundary (#8452; idea from @KMGeon's #8453).
+    it('getStaleDispatches keeps a fresh row just after a UTC-midnight threshold (#8452)', () => {
+      const d = createDb()
+
+      const ctx = d.createDispatchContext(d.createTask({ spec: 'midnight' }).id, 'term_midnight')
+      setDispatchTimes(d, ctx.id, '2026-05-04 00:04:00')
+
+      const stale = d.getStaleDispatches('2026-05-04T00:00:00.000Z')
+      expect(stale).toEqual([])
+    })
+
+    // Guards the last_heartbeat_at half of the fix on its own: a worker
+    // dispatched long before the threshold (stale under either format) that
+    // just sent a fresh space-format heartbeat must stay fresh (#8452).
+    it('getStaleDispatches keeps a live worker with a fresh space-format heartbeat (#8452)', () => {
+      const d = createDb()
+
+      const ctx = d.createDispatchContext(d.createTask({ spec: 'live' }).id, 'term_live')
+      setDispatchTimes(d, ctx.id, '2026-07-12 10:00:00', '2026-07-12 11:59:00')
+
+      const stale = d.getStaleDispatches('2026-07-12T11:55:00.000Z')
+      expect(stale).toEqual([])
+    })
+
     it('getThreadMessagesFor returns only same-thread replies to a handle', () => {
       const d = createDb()
       const outbound = d.insertMessage({

src/main/runtime/orchestration/db.ts

@@ -798,17 +798,20 @@ export class OrchestrationDb {
   // failed / circuit_broken row with an old-or-null last_heartbeat_at would
   // warn every tick (warning storm). Without `dispatched_at < :threshold`,
   // a freshly-dispatched worker would trip the warning during its first
-  // heartbeat interval (false positive). Callers supply the threshold as an
-  // ISO timestamp so the SQLite string-compare ordering works correctly
-  // (ISO-8601 compares lexicographically in time order).
+  // heartbeat interval (false positive). The stored columns are space-format
+  // (datetime('now'), "2026-07-12 12:00:00") while the threshold is ISO-Z, so
+  // raw TEXT ordering compares ' ' (0x20) below 'T' (0x54) at index 10 and
+  // flags fresh same-date rows as stale (#8452). julianday() parses both
+  // formats as UTC for a correct numeric comparison; a malformed timestamp
+  // yields NULL, so that row simply isn't flagged.
   getStaleDispatches(thresholdIso: string): DispatchContextRow[] {
     return this.db
       .prepare(
         `SELECT * FROM dispatch_contexts
          WHERE status = 'dispatched'
            AND dispatched_at IS NOT NULL
-           AND dispatched_at < ?
-           AND (last_heartbeat_at IS NULL OR last_heartbeat_at < ?)`
+           AND julianday(dispatched_at) < julianday(?)
+           AND (last_heartbeat_at IS NULL OR julianday(last_heartbeat_at) < julianday(?))`
       )
       .all(thresholdIso, thresholdIso) as DispatchContextRow[]
   }