fix(cron): prevent recomputeNextRuns from skipping due jobs in onTimer (#9823)

* fix(cron): prevent recomputeNextRuns from skipping due jobs in onTimer

ensureLoaded(forceReload) called recomputeNextRuns before runDueJobs,
which recalculated nextRunAtMs to a strictly future time. Since
setTimeout always fires a few ms late, the due check (now >= nextRunAtMs)
always failed and every/cron jobs never executed. Fixes #9788.

* docs: add changelog entry for cron timer race fix (#9823) (thanks @pycckuu)

---------

Co-authored-by: Tyler Yust <TYTYYUST@YAHOO.COM>

src/cron/service/store.ts

@@ -126,7 +126,15 @@ async function getFileMtimeMs(path: string): Promise<number | null> {
   }
 }
 
-export async function ensureLoaded(state: CronServiceState, opts?: { forceReload?: boolean }) {
+export async function ensureLoaded(
+  state: CronServiceState,
+  opts?: {
+    forceReload?: boolean;
+    /** Skip recomputing nextRunAtMs after load so the caller can run due
+     *  jobs against the persisted values first (see onTimer). */
+    skipRecompute?: boolean;
+  },
+) {
   // Fast path: store is already in memory. Other callers (add, list, run, …)
   // trust the in-memory copy to avoid a stat syscall on every operation.
   if (state.store && !opts?.forceReload) {
@@ -255,8 +263,9 @@ export async function ensureLoaded(state: CronServiceState, opts?: { forceReload
   state.storeLoadedAtMs = state.deps.nowMs();
   state.storeFileMtimeMs = fileMtimeMs;
 
-  // Recompute next runs after loading to ensure accuracy
-  recomputeNextRuns(state);
+  if (!opts?.skipRecompute) {
+    recomputeNextRuns(state);
+  }
 
   if (mutated) {
     await persist(state);

src/cron/service/timer.ts

@@ -1,7 +1,12 @@
 import type { HeartbeatRunResult } from "../../infra/heartbeat-wake.js";
 import type { CronJob } from "../types.js";
 import type { CronEvent, CronServiceState } from "./state.js";
-import { computeJobNextRunAtMs, nextWakeAtMs, resolveJobPayloadTextForMain } from "./jobs.js";
+import {
+  computeJobNextRunAtMs,
+  nextWakeAtMs,
+  recomputeNextRuns,
+  resolveJobPayloadTextForMain,
+} from "./jobs.js";
 import { locked } from "./locked.js";
 import { ensureLoaded, persist } from "./store.js";
 
@@ -36,8 +41,12 @@ export async function onTimer(state: CronServiceState) {
   state.running = true;
   try {
     await locked(state, async () => {
-      await ensureLoaded(state, { forceReload: true });
+      // Reload persisted due-times without recomputing so runDueJobs sees
+      // the original nextRunAtMs values.  Recomputing first would advance
+      // every/cron slots past the current tick when the timer fires late (#9788).
+      await ensureLoaded(state, { forceReload: true, skipRecompute: true });
       await runDueJobs(state);
+      recomputeNextRuns(state);
       await persist(state);
       armTimer(state);
     });