fix: prevent duplicate cron runs across hot reloads

src/cron/service/locked.ts

@@ -1,11 +1,22 @@
 import type { CronServiceState } from "./state.js";
 
-export async function locked<T>(state: CronServiceState, fn: () => Promise<T>): Promise<T> {
-  const next = state.op.then(fn, fn);
-  // Keep the chain alive even when the operation fails.
-  state.op = next.then(
+const storeLocks = new Map<string, Promise<void>>();
+
+const resolveChain = (promise: Promise<unknown>) =>
+  promise.then(
     () => undefined,
     () => undefined,
   );
+
+export async function locked<T>(state: CronServiceState, fn: () => Promise<T>): Promise<T> {
+  const storePath = state.deps.storePath;
+  const storeOp = storeLocks.get(storePath) ?? Promise.resolve();
+  const next = Promise.all([resolveChain(state.op), resolveChain(storeOp)]).then(fn);
+
+  // Keep the chain alive even when the operation fails.
+  const keepAlive = resolveChain(next);
+  state.op = keepAlive;
+  storeLocks.set(storePath, keepAlive);
+
   return (await next) as T;
 }

src/cron/service/store.ts

@@ -4,8 +4,15 @@ import type { CronJob } from "../types.js";
 import { inferLegacyName, normalizeOptionalText } from "./normalize.js";
 import type { CronServiceState } from "./state.js";
 
+const storeCache = new Map<string, { version: 1; jobs: CronJob[] }>();
+
 export async function ensureLoaded(state: CronServiceState) {
   if (state.store) return;
+  const cached = storeCache.get(state.deps.storePath);
+  if (cached) {
+    state.store = cached;
+    return;
+  }
   const loaded = await loadCronStore(state.deps.storePath);
   const jobs = (loaded.jobs ?? []) as unknown as Array<Record<string, unknown>>;
   let mutated = false;
@@ -35,6 +42,7 @@ export async function ensureLoaded(state: CronServiceState) {
     }
   }
   state.store = { version: 1, jobs: jobs as unknown as CronJob[] };
+  storeCache.set(state.deps.storePath, state.store);
   if (mutated) await persist(state);
 }