refactor(bridge/core): daily performance optimization audit

[repyh]

This pull request executes the daily performance and optimization audit for bridge/core and eventloop/eventloop.go.

Changes Made:

1. Interface Boxing & Allocations (bridge/core/reflection.go):
   • Swapped v.MapKeys() to v.MapRange() in bindMap to avoid intermediate slice allocations.
   • Replaced fmt.Sprint(key.Interface()) with a switch checking numeric kinds and using strconv.FormatInt/Uint. This prevents boxing numbers into interface{}.
2. []byte Fast Path (bridge/core/reflection.go & arraybuffer.go):
   • Implemented a fast path in bindSlice to securely handle []byte values. If addressable, v.Bytes() is used; otherwise, it falls back gracefully.
   • Introduced ToUint8Array to convert Go byte slices into JavaScript Uint8Array instances with safe fallbacks if the global doesn't exist.
   • Deeply copies the array prior to initializing Uint8Array to avert JavaScript from mutating the host memory block.
3. Cache Locality (eventloop/eventloop.go):
   • Re-organized the EventLoop struct to couple the running and autoStop boolean properties directly beside their protecting mu Mutex, optimizing cache line efficiency.
4. Panic Protection (eventloop/eventloop.go):
   • Integrated sync.Once in CreatePromise callbacks to reliably ensure el.wg.Done() is fired precisely once, forestalling sync.WaitGroup underflow panics if JavaScript invokes resolve/reject repetitively.

All features run flawlessly per existing unit, e2e, and integration tests. Evaluated through make test & go test -v ./....

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PR created automatically by Jules for task 16463292254535626834 started by @repyh

Summary by CodeRabbit

• Bug Fixes

  • Fixed potential race condition in promise resolution handling.

• Performance Improvements

  • Optimized byte array conversions for better performance.
  • Improved map iteration efficiency.
  • Enhanced key type handling for maps with various key types.

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[coderabbitai]

📝 Walkthrough

Walkthrough

This PR adds safe Go-to-JavaScript byte array conversion, optimizes map iteration and key formatting in the JS bridge reflection layer, and hardens promise settlement in the EventLoop to prevent duplicate callback executions and memory leaks.

Changes

JS bridge and EventLoop improvements

Layer / File(s)	Summary
Uint8Array conversion helper and byte slice optimization bridge/core/arraybuffer.go, bridge/core/reflection.go	ToUint8Array converts Go byte slices to JS Uint8Array with ArrayBuffer fallback. bindSlice detects []byte, copies the data, and uses the helper to prevent JS mutations of Go memory.
Map iteration and numeric key optimization bridge/core/reflection.go	bindMap replaces MapKeys() iteration with MapRange() for efficiency and uses strconv for integer/unsigned numeric keys while preserving fmt.Sprint fallback.
EventLoop promise settlement idempotency eventloop/eventloop.go	EventLoop field reordering improves cache locality. CreatePromise wraps resolve and reject callbacks with sync.Once to ensure JS-thread settlement and WaitGroup decrement occur only once regardless of callback repetition.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~22 minutes

Poem

🐰 A rabbit hops through typed arrays bright,
Promise once-guards settle right,
Maps iterate with range so keen,
Cache-lined fields keep code clean,
Memory safe, no leaks in sight! 🎉

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The title 'refactor(bridge/core): daily performance optimization audit' is vague and generic; it uses non-specific terms like 'daily' and 'audit' that don't clearly convey the actual technical changes made.	Revise the title to be more specific about the main changes, such as 'refactor(bridge/core): optimize map iteration and byte slice conversion' to better reflect the actual improvements in MapRange, strconv usage, and ToUint8Array implementation.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch daily-optimization-bridge-core-16463292254535626834

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[coderabbitai]

🧹 Nitpick comments (1)

bridge/core/reflection.go (1)

381-389: ⚡ Quick win

This optimization is intentional and currently has no impact on the codebase.

The recent change from fmt.Sprint(key.Interface()) to strconv for numeric keys was an intentional performance optimization (commit 230d8d1). However, there are no named numeric types with String() methods in the codebase, so no existing serialization behavior has changed. The default case still uses fmt.Sprint(key.Interface()) as a fallback.

If named numeric types with custom String() methods are added in the future and used as map keys, they would lose their custom string output. The suggested fix is valid defensive programming but addresses a hypothetical rather than an actual problem. If this pattern becomes a concern, it could be addressed then.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@bridge/core/reflection.go` around lines 381 - 389, The numeric key branches
(switch on key.Kind()) currently format numbers with
strconv.FormatInt/FormatUint which will bypass any custom String()
implementations on named numeric types; update the numeric cases in the switch
that handle reflect.Int*/reflect.Uint* to first detect if the key's type
implements fmt.Stringer (use reflect.TypeOf((*fmt.Stringer)(nil)).Elem() and
key.Type().Implements(...)) and if so set keyStr = fmt.Sprint(key.Interface()),
otherwise fall back to strconv.FormatInt(key.Int(), 10) or
strconv.FormatUint(key.Uint(), 10); keep the existing reflect.String case and
the default fmt.Sprint fallback.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@bridge/core/reflection.go`:
- Around line 381-389: The numeric key branches (switch on key.Kind()) currently
format numbers with strconv.FormatInt/FormatUint which will bypass any custom
String() implementations on named numeric types; update the numeric cases in the
switch that handle reflect.Int*/reflect.Uint* to first detect if the key's type
implements fmt.Stringer (use reflect.TypeOf((*fmt.Stringer)(nil)).Elem() and
key.Type().Implements(...)) and if so set keyStr = fmt.Sprint(key.Interface()),
otherwise fall back to strconv.FormatInt(key.Int(), 10) or
strconv.FormatUint(key.Uint(), 10); keep the existing reflect.String case and
the default fmt.Sprint fallback.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 44aad6c1-6a55-4553-ae9e-ba89d38f7ea4

📥 Commits

Reviewing files that changed from the base of the PR and between b85f440 and 230d8d1.

📒 Files selected for processing (3)

• bridge/core/arraybuffer.go
• bridge/core/reflection.go
• eventloop/eventloop.go