fix: avoid crash on user's CPU does not support simd

[PupilTong]

Summary by CodeRabbit

• Bug Fixes

  • Fixed a crash on systems with CPUs that lack SIMD support.

• Improvements

  • Strengthened runtime capability detection to ensure all required CPU features are present before initializing WASM components, improving stability and compatibility.

• Tests

  • Updated test environment to cover SIMD-capable scenarios to prevent regressions.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).
• Changeset added, and when a BREAKING CHANGE occurs, it needs to be clearly marked (or not required).

[changeset-bot]

🦋 Changeset detected

Latest commit: fef070c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 11 packages

Name	Type
@lynx-js/web-core	Patch
upgrade-rspeedy	Patch
@lynx-js/web-rsbuild-server-middleware	Patch
@lynx-js/web-core-server	Patch
@lynx-js/web-constants	Patch
@lynx-js/web-mainthread-apis	Patch
@lynx-js/web-worker-rpc	Patch
@lynx-js/web-worker-runtime	Patch
@lynx-js/rspeedy	Patch
@lynx-js/web-core-wasm	Patch
create-rspeedy	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds SIMD detection alongside reference-types for WASM feature checks, gating WASM bundle loading on both features; updates tests to mock SIMD and adds a changelog entry documenting a fix for SIMD-related crashes.

Changes

Cohort / File(s)	Summary
Changelog .changeset/bitter-mails-boil.md	Adds a patch changelog entry noting a fix to avoid crashes on CPUs lacking SIMD support.
Test Mocks packages/web-platform/web-core-wasm/tests/StyleManager.spec.ts, packages/web-platform/web-core-wasm/tests/template-manager.spec.ts	Adds simd: async () => true to the wasm-feature-detect mocks so tests exercise SIMD-enabled code paths.
Client WASM loader packages/web-platform/web-core-wasm/ts/client/wasm.ts	Imports simd and runs Promise.all([referenceTypes(), simd()]); requires both referenceTypes and simd to be true before loading/compiling the wasm, otherwise rejects with "WASM not supported".
Main-thread WASM init packages/web-platform/web-mainthread-apis/wasm/index.js	Adds simd import and parallelizes feature detection with Promise.all, switching between standard and legacy wasm chunks based on combined feature support.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• fix: crash on chrome<96 #1361: Modifies WASM feature-detection and conditional-loading logic; this change extends that mechanism to also require SIMD support.

Suggested reviewers

• Sherry-hue
• colinaaa

Poem

🐇 I sniff the CPU, twitch my nose,
I check for lanes where SIMD goes.
Two features paired, a careful hop,
Now WASM loads — or we politely stop. ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change in the pull request: adding SIMD feature detection to prevent crashes on CPUs without SIMD support.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In @.changeset/bitter-mails-boil.md:
- Line 5: The release note line "fix: avoid crash on user's CPU does not support
simd" is grammatically awkward; update the text to a clear, concise phrasing
such as "fix: avoid crash when user's CPU does not support SIMD" (or "fix: avoid
crash on CPUs without SIMD support") to improve clarity and tone—edit the string
in .changeset/bitter-mails-boil.md accordingly.

🧹 Nitpick comments (1)

packages/web-platform/web-core-wasm/ts/client/wasm.ts (1)

6-38: Refactor to async/await for clarity in feature-detection flow.

The feature detection resolves to boolean values (true/false) rather than rejecting, so the current code is safe. However, the async/await pattern aligns better with the project's TypeScript/JavaScript guidelines and makes the conditional logic more readable.

♻️ Suggested refactor

-const wasmLoaded = Promise.all([referenceTypes(), simd()]).then(
-  ([supportsReferenceTypes, supportsSimd]) => {
-    if (supportsReferenceTypes && supportsSimd) {
-      return Promise.all([
-        import(
-          /* webpackMode: "eager" */
-          /* webpackFetchPriority: "high" */
-          /* webpackPrefetch: true */
-          /* webpackPreload: true */
-          '../../binary/client/client.js'
-        ),
-        isWorker ? undefined : WebAssembly.compileStreaming(
-          fetch(
-            new URL(
-              /* webpackChunkName: "standard-wasm" */
-              /* webpackMode: "eager" */
-              /* webpackFetchPriority: "high" */
-              /* webpackPrefetch: true */
-              /* webpackPreload: true */
-              '../../binary/client/client_bg.wasm',
-              import.meta.url,
-            ),
-          ),
-        ),
-      ]);
-    } else {
-      throw new Error('WASM not supported');
-    }
-  },
-);
+const wasmLoaded = (async () => {
+  const [supportsReferenceTypes, supportsSimd] = await Promise.all([
+    referenceTypes(),
+    simd(),
+  ]);
+  if (!supportsReferenceTypes || !supportsSimd) {
+    throw new Error('WASM not supported');
+  }
+  return Promise.all([
+    import(
+      /* webpackMode: "eager" */
+      /* webpackFetchPriority: "high" */
+      /* webpackPrefetch: true */
+      /* webpackPreload: true */
+      '../../binary/client/client.js'
+    ),
+    isWorker ? undefined : WebAssembly.compileStreaming(
+      fetch(
+        new URL(
+          /* webpackChunkName: "standard-wasm" */
+          /* webpackMode: "eager" */
+          /* webpackFetchPriority: "high" */
+          /* webpackPrefetch: true */
+          /* webpackPreload: true */
+          '../../binary/client/client_bg.wasm',
+          import.meta.url,
+        ),
+      ),
+    ),
+  ]);
+})();

[codecov]

Codecov Report

❌ Patch coverage is 68.00000% with 8 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...ges/web-platform/web-mainthread-apis/wasm/index.js	0.00%	6 Missing ⚠️
...kages/web-platform/web-core-wasm/ts/client/wasm.ts	89.47%	2 Missing ⚠️

📢 Thoughts on this report? Let us know!

[codspeed-hq]

Merging this PR will degrade performance by 8.67%

⚡ 1 improved benchmark
❌ 1 regressed benchmark
✅ 61 untouched benchmarks
⏩ 3 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	basic-performance-nest-level-100	7.1 ms	7.8 ms	-8.67%
⚡	basic-performance-small-css	8.2 ms	7.8 ms	+5.98%

---

_{Comparing PupilTong:p/hw/fix-simd128-issue (fef070c) with main (f7133c1)²}

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. ↩

2. No successful run was found on main (4d91dd3) during the generation of this report, so f7133c1 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[relativeci]

Web Explorer

#7315 Bundle Size — 384.14KiB (+0.05%).

fef070c(current) vs f7133c1 main#7309(baseline)

Bundle metrics   1 change

	Current #7315	Baseline #7309
Initial JS	154.12KiB	154.12KiB
Initial CSS	35.05KiB	35.05KiB
Cache Invalidation	7.5%	7.45%
Chunks	8	8
Assets	8	8
Modules	238	238
Duplicate Modules	16	16
Duplicate Code	2.99%	2.99%
Packages	4	4
Duplicate Packages	0	0

Bundle size by type   1 change 1 regression

	Current #7315	Baseline #7309
JS	252.07KiB (+0.07%)	251.89KiB
Other	97.02KiB	97.02KiB
CSS	35.05KiB	35.05KiB

Bundle analysis report Branch PupilTong:p/hw/fix-simd128-issue Project dashboard

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