chore: fix flaky main thread tests #1377

PupilTong · 2025-07-30T07:19:03Z

Summary by CodeRabbit

Chores
- Added asynchronous initialization for WebAssembly to improve startup readiness of components.

changeset-bot · 2025-07-30T07:19:06Z

⚠️ No Changeset found

Latest commit: cb9feea

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coderabbitai · 2025-07-30T07:19:09Z

📝 Walkthrough

Walkthrough

An import statement for the initWasm function from the @lynx-js/web-style-transformer package is added to the test file. The code now awaits the asynchronous initialization of WebAssembly at the module's top level. No other logic or exported entities are changed.

Changes

Cohort / File(s)	Change Summary
WebAssembly Initialization in Test `packages/web-platform/web-tests/shell-project/mainthread-test.ts`	Added import and top-level await for `initWasm` from `@lynx-js/web-style-transformer` to initialize WebAssembly before executing the rest of the module.
Dependency Addition `packages/web-platform/web-tests/package.json`	Added `@lynx-js/web-style-transformer` as a development dependency with version specifier `workspace:*`.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Possibly related PRs

fix: crash on chrome<96 #1361: Modifies the initWasm function to conditionally load different WASM modules based on browser support, directly related to the WebAssembly initialization used here.

Suggested reviewers

Sherry-hue

Poem

A bunny hops through lines of code,
Awaiting WASM to lighten the load.
With imports neat and modules new,
Initialization hops right through!
The test now starts with ears upright,
Ready for WebAssembly’s bytey bite.
🐇✨

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📒 Files selected for processing (2)

packages/web-platform/web-tests/package.json (1 hunks)
packages/web-platform/web-tests/shell-project/mainthread-test.ts (1 hunks)

✅ Files skipped from review due to trivial changes (2)

packages/web-platform/web-tests/package.json
packages/web-platform/web-tests/shell-project/mainthread-test.ts

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coderabbitai

Actionable comments posted: 1

🧹 Nitpick comments (2)

packages/web-platform/web-tests/shell-project/mainthread-test.ts (2)
7-7: Consider using a more direct import path.

The nested node_modules path in the import is unusual and potentially fragile. This could break if the dependency structure changes or in different installation contexts.

Consider importing directly from the package:
-import { initWasm } from '@lynx-js/web-mainthread-apis/node_modules/@lynx-js/web-style-transformer';
+import { initWasm } from '@lynx-js/web-style-transformer';
Or verify if this nested import is intentional due to specific dependency resolution requirements.

8-8: Good fix for flaky tests, consider adding error handling.

Initializing WebAssembly synchronously before test setup is a solid approach to fix race condition issues that could cause flaky tests. The top-level await ensures WebAssembly is ready before any test logic runs.

Consider adding error handling to make failures more explicit:
-await initWasm();
+try {
+  await initWasm();
+} catch (error) {
+  console.error('Failed to initialize WebAssembly:', error);
+  throw error;
+}

📜 Review details

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Reviewing files that changed from the base of the PR and between 92445ad and 4a0849f.

📒 Files selected for processing (1)

packages/web-platform/web-tests/shell-project/mainthread-test.ts (1 hunks)

🧰 Additional context used

🧠 Learnings (1)

📓 Common learnings

Learnt from: PupilTong
PR: lynx-family/lynx-stack#1029
File: packages/web-platform/web-core/src/uiThread/createRenderAllOnUI.ts:95-99
Timestamp: 2025-07-16T05:57:29.837Z
Learning: In the lynx-stack codebase, PupilTong prefers avoiding regex for parsing in performance-critical code paths like SSR hydration, preferring simple string manipulation operations even if they're less robust, when the input format is predictable and controlled.

🧬 Code Graph Analysis (1)

packages/web-platform/web-tests/shell-project/mainthread-test.ts (1)

packages/web-platform/web-style-transformer/index.js (1)

initWasm (3-23)

packages/web-platform/web-tests/shell-project/mainthread-test.ts

codecov · 2025-07-30T07:57:23Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

📢 Thoughts on this report? Let us know!

codspeed-hq · 2025-07-30T08:02:35Z

CodSpeed Performance Report

Merging #1377 will not alter performance

_{Comparing PupilTong:p/hw/fix-main-thread-test (cb9feea) with main (92445ad)}

Summary

✅ 10 untouched benchmarks

relativeci · 2025-07-30T08:09:54Z

React Example

#3451 Bundle Size — 235.18KiB (0%).

cb9feea(current) vs a4ee4fd main#3450(baseline)

Bundle metrics no changes

	Current #3451	Baseline #3450
Initial JS	`0B`	`0B`
Initial CSS	`0B`	`0B`
Cache Invalidation	`0%`	`0%`
Chunks	`0`	`0`
Assets	`4`	`4`
Modules	`156`	`156`
Duplicate Modules	`63`	`63`
Duplicate Code	`45.94%`	`45.94%`
Packages	`2`	`2`
Duplicate Packages	`0`	`0`

Bundle size by type no changes

	Current #3451	Baseline #3450
IMG	`145.76KiB`	`145.76KiB`
Other	`89.42KiB`	`89.42KiB`

Bundle analysis report Branch PupilTong:p/hw/fix-main-thread-t... Project dashboard

^{Generated by RelativeCI Documentation Report issue}

relativeci · 2025-07-30T08:09:56Z

Web Explorer

#3441 Bundle Size — 352.53KiB (0%).

cb9feea(current) vs a4ee4fd main#3440(baseline)

Bundle metrics

1 change

	Current #3441	Baseline #3440
Initial JS	`142.12KiB`	`142.12KiB`
Initial CSS	`31.83KiB`	`31.83KiB`
Cache Invalidation	`0%`	`0%`
Chunks	`7`	`7`
Assets	`7`	`7`
Modules	`215`(`+0.47%`)	`214`
Duplicate Modules	`17`	`17`
Duplicate Code	`3.94%`	`3.94%`
Packages	`4`	`4`
Duplicate Packages	`0`	`0`

Bundle size by type no changes

	Current #3441	Baseline #3440
JS	`226.4KiB`	`226.4KiB`
Other	`94.29KiB`	`94.29KiB`
CSS	`31.83KiB`	`31.83KiB`

Bundle analysis report Branch PupilTong:p/hw/fix-main-thread-t... Project dashboard

^{Generated by RelativeCI Documentation Report issue}

chore: fix flaky main thread tests

4a0849f

PupilTong self-assigned this Jul 30, 2025

coderabbitai bot added the platform:Web label Jul 30, 2025

coderabbitai bot reviewed Jul 30, 2025

View reviewed changes

packages/web-platform/web-tests/shell-project/mainthread-test.ts Outdated Show resolved Hide resolved

fix

cb9feea

PupilTong requested a review from colinaaa July 30, 2025 09:06

colinaaa approved these changes Jul 30, 2025

View reviewed changes

colinaaa added this pull request to the merge queue Jul 30, 2025

Merged via the queue into lynx-family:main with commit a8c8e39 Jul 30, 2025
70 of 76 checks passed

coderabbitai bot mentioned this pull request Sep 11, 2025

feat(web): add simple support for rpx unit #1654

Closed

3 tasks

chore: fix flaky main thread tests #1377

chore: fix flaky main thread tests #1377

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