diigo-cache: dispose RPC stubs after each fetch; one fetch per miss

Two bugs in page()'s miss path, found while building the fill job:

- the webapp stubs (app, pathjoin, query) were never disposed, which
  kept the DO from being evicted (evictDurableObject hung after a single
  miss); they are now disposed once the page is in hand
- a miss on page n > 1 also fetched page 1 and threw it away, doubling
  diigo calls; every page carries `total`, so only page n is fetched

Regression test: a miss, then eviction, then a cache hit. tsconfig adds
the ESNext.Disposable lib for Symbol.dispose.

Generated-by: Claude Opus 5.5

diigo-cache/src/cache.ts

@@ -72,6 +72,12 @@ export type FillStatus = {
 	error?: string;
 };
 
+/** release an RPC stub, if it is one (plain objects are left alone) */
+function disposeStub(stub: unknown): void {
+	const dispose = (stub as { [Symbol.dispose]?: () => void } | null)?.[Symbol.dispose];
+	if (typeof dispose === "function") dispose.call(stub);
+}
+
 function sleep(ms: number): Promise<void> {
 	return new Promise((r) => setTimeout(r, ms));
 }
@@ -145,8 +151,8 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 
 	/**
 	 * read page `pageNum` (`count` per page, diigo's updated-desc order):
-	 * storage first; on miss, fetch through the webapp instance (etching
+	 * storage first; on miss, fetch that one page through the webapp
-	 * page 1 alongside — it carries `total`) and etch. Cache provenance
+	 * instance (every page carries `total`) and etch. Cache provenance
 	 * rides in the result (`cached`).
 	 */
 	async page(pageNum: number, count: number): Promise<CachePage> {
@@ -170,17 +176,17 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 			return hit;
 		}
 
+		// RPC stubs (the app and each pipelined step) are disposed once the
+		// page is in hand: undisposed stubs keep this DO from being evicted
 		const app = await this.env.WEBAPP.at(init.webappId);
-		const fetchPage = (n: number): Promise<{ total: number; items: Item[] }> =>
+		const joined = app.pathjoin("load_user_items");
-			app
+		const queried = joined.query({ sort: "updated", count, page_num: pageNum });
-				.pathjoin("load_user_items")
+		let data: { total: number; items: Item[] };
-				.query({ sort: "updated", count, page_num: n })
+		try {
-				.get()
+			data = JSON.parse(await queried.get()) as { total: number; items: Item[] };
-				.then((t) => JSON.parse(t)) as Promise<{ total: number; items: Item[] }>;
+		} finally {
-
+			for (const stub of [queried, joined, app]) disposeStub(stub);
-		// a miss on page n>1 etches page 1 first (it carries `total`)
+		}
-		const first = await fetchPage(1);
-		const data = pageNum === 1 ? first : await fetchPage(pageNum);
 		const kept = this.keep(toRows(data.items, console));
 		// fetched vs kept: the public cache's drop of private rows shows here
 		console.log({ event: "cache", kind: this.kind, page: pageNum, outcome: "miss", fetched: data.items.length, kept: kept.length });

diigo-cache/tests/caches.test.ts

@@ -1,5 +1,5 @@
 import { env } from "cloudflare:workers";
-import { runInDurableObject } from "cloudflare:test";
+import { evictDurableObject, runInDurableObject } from "cloudflare:test";
 import { describe, expect, it, vi } from "vitest";
 import worker from "../src/index.js";
 import { toWebkey } from "../src/webkeys.js";
@@ -68,6 +68,16 @@ describe("PublicCache", () => {
 	});
 });
 
+describe("eviction", () => {
+	it("a cache miss leaves no undisposed RPC stubs to block eviction", async () => {
+		const stub = testEnv.CACHE_DO.get(testEnv.CACHE_DO.newUniqueId());
+		await stub.setup({ webappId: WEBAPP_ID });
+		await stub.page(1, 24);
+		await evictDurableObject(stub);
+		expect((await stub.page(1, 24)).cached).toBe(true);
+	}, 3000);
+});
+
 describe("DiigoCache", () => {
 	it("keeps every item of a page, each under its own link_id", async () => {
 		const stub = testEnv.CACHE_DO.get(testEnv.CACHE_DO.newUniqueId());

diigo-cache/tsconfig.json

@@ -7,6 +7,7 @@
 		"esModuleInterop": true,
 		"verbatimModuleSyntax": true,
 		"skipLibCheck": true,
+		"lib": ["ES2022", "ESNext.Disposable"],
 		"noEmit": true,
 		"types": []
 	},