Turbopack: Fix flake in task_statistics unit test

[bgw]

If we don't explicitly return a Vc::cell(()) here, then <() as dyn turbo_tasks::vc::default::ValueDefault>::value_default gets called in a non-deterministic way.

That's not something we care about testing here, so just add a an explicit Vc::cell(()) call to avoid it.

[bgw]

• Turbopack: Update rust toolchain to nightly-2026-02-18 #89974
• Turbopack: Fix flake in task_statistics unit test #89981 👈 (View in Graphite)
• canary

This stack of pull requests is managed by Graphite. Learn more about stacking.

[bgw]

I'll merge bypassing requirements once https://github.com/vercel/next.js/actions/runs/22003821408/job/63583074340?pr=89981 passes

[nextjs-bot]

Failing test suites

Commit: b2223f8 | About building and testing Next.js

pnpm test-start-turbo test/e2e/app-dir/segment-cache/revalidation/segment-cache-revalidation.test.ts (turbopack) (job)

• segment cache (revalidation) > delay re-prefetch after revalidation to allow CDN propagation (DD)

Expand output

● segment cache (revalidation) › delay re-prefetch after revalidation to allow CDN propagation

page.waitForSelector: Timeout 5000ms exceeded.
Call log:
  - waiting for locator('#greeting') to be visible

  519 |
  520 |     return this.startChain(async () => {
> 521 |       const el = await page.waitForSelector(selector, {
      |                             ^
  522 |         timeout,
  523 |         state,
  524 |       })

  at waitForSelector (lib/browsers/playwright.ts:521:29)
  at Playwright._chain (lib/browsers/playwright.ts:651:23)
  at Playwright._chain [as startChain] (lib/browsers/playwright.ts:632:17)
  at Playwright.startChain [as waitForElementByCss] (lib/browsers/playwright.ts:520:17)
  at Playwright.waitForElementByCss [as elementByCss] (lib/browsers/playwright.ts:405:17)
  at Playwright.elementByCss [as elementById] (lib/browsers/playwright.ts:425:17)
  at elementById (e2e/app-dir/segment-cache/revalidation/segment-cache-revalidation.test.ts:371:38)
  at act (lib/router-act.ts:296:27)
  at Object.<anonymous> (e2e/app-dir/segment-cache/revalidation/segment-cache-revalidation.test.ts:366:5)

pnpm test-dev-turbo test/e2e/app-dir/actions/app-action.test.ts (turbopack) (job)

Expand output

● Test suite failed to run

Jest encountered an unexpected token

Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.

By default "node_modules" folder is ignored by transformers.

Here's what you can do:
 • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
 • If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
 • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
 • If you need a custom transformation specify a "transform" option in your config.
 • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/configuration
For information about custom transformations, see:
https://jestjs.io/docs/code-transformation

Details:

/root/actions-runner/_work/next.js/next.js/test/e2e/app-dir/actions/app-action.test.ts:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import { FileRef, nextTestSetup } from 'e2e-utils';
                                                                                  ^^^^^^

SyntaxError: Cannot use import statement outside a module

  at Runtime.createScriptFromCode (../node_modules/.pnpm/jest-runtime@29.7.0/node_modules/jest-runtime/build/index.js:1505:14)

[codspeed-hq]

Merging this PR will not alter performance

✅ 17 untouched benchmarks
⏩ 3 skipped benchmarks¹

---

_{Comparing bgw/fix-task-statistics-flake (b2223f8) with canary (a7f5106)}

Footnotes

1. 3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩