[2.0 / next] A memo's own isPending(heldX) answers false when the memo is pulled inside latest(), true when a plain read wakes it #4468

import { afterEach, beforeEach, expect, test, vi } from "vitest";
import { action, createMemo, createRenderEffect, createRoot, createSignal, flush, isPending, latest } from "../src/index.js";

beforeEach(() => vi.useFakeTimers());
afterEach(() => vi.useRealTimers());
const sleep = (ms: number) => new Promise<void>(r => setTimeout(r, ms));

for (const form of ["pulled", "plainFirst"] as const)
  test(`memo's own isPending(held x) is the same whoever wakes it (${form})`, async () => {
    const [x, setX] = createSignal(0);
    const [s, setS] = createSignal(0);
    const [on, setOn] = createSignal(false);
    const seen: unknown[] = [];
    createRoot(() => {
      createRenderEffect(x, () => {});
      const sa = createMemo(() => s());
      const m = createMemo(() => `${sa()}:${isPending(x)}`);
      createRenderEffect(
        () => (on() ? (form === "pulled" ? latest(() => m()) : (m(), latest(m))) : "off"),
        v => void seen.push(v)
      );
    });
    flush();
    action(function* () { setX(1); yield sleep(100); })();
    flush();
    setS(1);
    setOn(true);
    flush();
    expect(seen[seen.length - 1]).toBe("1:true");
    await vi.advanceTimersByTimeAsync(150);
    flush();
  });