test: debug fork CI timing shard assignment

[devjiwonchoi]

Why?

Investigate whether fork pull requests create an empty test-timings.json artifact and then assign test prod (5/10) using equal weights, which can overload that shard.

How?

Add temporary debug output before test-prod-react--5/10 runs. The diagnostic logs the timing artifact byte size, timing entry count, assigned shard size, accumulated previous timing, missing timing count, and assigned test files.

Verification

• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/build_reusable.yml"); puts "yaml ok"'\n- node --check /tmp/next-ci-debug-shard.js\n- git diff --check\n- Not run: pnpm prettier --check .github/workflows/build_reusable.yml (fresh debug worktree has no local dependencies installed)\n\n

[github-actions]

Failing test suites

Commit: 5e14265 | About building and testing Next.js

pnpm test-dev test/development/app-dir/hmr-intercept-routes/hmr-intercept-routes.test.ts (job)

• hmr-intercept-routes > should update intercept routes via HMR (DD)

Expand output

● hmr-intercept-routes › should update intercept routes via HMR

page.waitForSelector: Timeout 10000ms exceeded.
Call log:
  - waiting for locator('#default-intercept') to be visible

  569 |
  570 |     return this.startChain(async () => {
> 571 |       const el = await page.waitForSelector(selector, {
      |                             ^
  572 |         timeout,
  573 |         state,
  574 |       })

  at waitForSelector (lib/browsers/playwright.ts:571:29)
  at Playwright._chain (lib/browsers/playwright.ts:701:23)
  at Playwright._chain [as startChain] (lib/browsers/playwright.ts:682:17)
  at Playwright.startChain [as waitForElementByCss] (lib/browsers/playwright.ts:570:17)
  at Object.waitForElementByCss (development/app-dir/hmr-intercept-routes/hmr-intercept-routes.test.ts:38:21)

[github-actions]

Stats cancelled

Commit: 5e14265
View workflow run