⚡ Bolt: Reuse Uint8Array and fast O(K) reset for visited tracker

[AhmmedSamier]

💡 What:
Replaced the per-search allocation of new Uint8Array(this.items.length) in SearchEngine.performUnifiedSearch with a reusable, class-level visitedBuffer and a visitedTracker array for fast O(K) clearing.

🎯 Why:
In the hot path of searching (especially burst/continuous searching), allocating a large array (proportional to total workspace items) and subsequently garbage collecting it creates significant memory pressure and pauses.

📊 Impact:
Reduces array allocation overhead on every search query to zero. The buffer is now cleared in O(K) time where K is only the number of items actually visited during the search, not the total size of the workspace items array. The burst search benchmark for "No match" scenario stays basically the same or slightly faster while avoiding huge memory swings.

🔬 Measurement:
Run cd language-server && bun run benchmarks/search_burst.bench.ts and verify memory usage metrics/execution times.

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PR created automatically by Jules for task 3281649880735625941 started by @AhmmedSamier

Summary by CodeRabbit

• Performance Improvements

  • Optimized search engine memory usage by reusing allocation buffers across repeated searches instead of creating new ones each time, reducing overhead and improving performance.

• Tests

  • Added benchmark results documenting search performance metrics across various scenarios.

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[coderabbitai]

📝 Walkthrough

Walkthrough

The search engine is refactored to eliminate per-search allocations of a visited tracking array by reusing an instance-level visitedBuffer (Uint8Array) and visitedTracker (number array). Helper methods switch from accepting an optional visited array parameter to a useVisited boolean flag that references the reusable instance state, which is cleared only after each search completes via try/finally cleanup.

Changes

Search Engine Deduplication Buffer Reuse

Layer / File(s)	Summary
Data Structure language-server/src/core/search-engine.ts	Instance fields visitedBuffer: Uint8Array and visitedTracker: number[] are added to track and reuse deduplication state across multiple searches.
Core Implementation language-server/src/core/search-engine.ts	performUnifiedSearch is refactored to compute useVisited, lazily allocate/resize visitedBuffer on demand, run searches with the boolean flag, and use try/finally to reset visited marks only for tracked indices before clearing the tracker.
Helper Methods language-server/src/core/search-engine.ts	searchWithIndices and searchAllItems replace the optional visited?: Uint8Array parameter with useVisited: boolean, consulting and updating this.visitedBuffer and this.visitedTracker directly when deduplication is enabled.
Embedded Patch language-server/apply_patch.sh	Patch file documenting the full implementation details of the reusable buffer mechanism and state management logic.
Benchmark Results language-server/benchmarks/results_burst.json	Benchmark results for "Burst Search" scenarios ("App", "Zzz", "S") with timing statistics (avgMs, totalMs, minMs, maxMs, p95Ms, stdDevMs).

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• AhmmedSamier/DeepLens#371: Directly modifies language-server/src/core/search-engine.ts to replace per-search index tracking with Uint8Array-based marker arrays in performUnifiedSearch and helper methods.
• AhmmedSamier/DeepLens#344: Replaces SearchEngine's heavier index-deduplication structures (Set/new per-call Uint8Array) with Uint8Array-based tracking, which this PR further optimizes by introducing a reusable instance-level buffer.
• AhmmedSamier/DeepLens#368: Modifies language-server/src/core/search-engine.ts to replace Set-based visited tracking with Uint8Array-based presence tracking; this PR extends that optimization with buffer reuse and signature changes to helper methods.

Poem

🐰 A rabbit hops through the warren with glee,

One tunnel reused instead of made new—

No waste of fresh burrows, just one buffer so free,

Each search leaves no footprints once searches are through! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main optimization: reusing a Uint8Array and implementing a fast O(K) reset mechanism for the visited tracker, which directly aligns with the changeset's core purpose of eliminating per-search allocations and reducing GC pressure.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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 bolt-fast-uint8array-reset-3281649880735625941

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[coderabbitai]

Actionable comments posted: 1

🤖 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.

Inline comments:
In `@language-server/src/core/search-engine.ts`:
- Around line 186-187: The clear() method currently doesn't reset the reusable
visited state, leaving a previously large Uint8Array retained; update the
clear() implementation to explicitly reset the visitedBuffer to a new
Uint8Array(0) and visitedTracker to an empty array (visitedBuffer = new
Uint8Array(0); visitedTracker = [];), alongside the existing cache/field resets
so the engine truly frees that memory when clearing state.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 28d062d2-9c1f-413a-acdd-baa042fd7c94

📥 Commits

Reviewing files that changed from the base of the PR and between 0b051a9 and 6917058.

📒 Files selected for processing (3)

• language-server/apply_patch.sh
• language-server/benchmarks/results_burst.json
• language-server/src/core/search-engine.ts

[coderabbitai]

⚠️ Potential issue | 🟠 Major | ⚡ Quick win

Reset reusable visited state when clearing engine state.

clear() (Line 756 onward) doesn’t reset the new visitedBuffer/visitedTracker, so a previously large Uint8Array can stay retained after a full clear. Please clear these alongside other caches.

💡 Proposed fix

     clear(): void {
         this.items = [];
@@
         this.inactiveFileItems = [];
+        this.visitedBuffer = new Uint8Array(0);
+        this.visitedTracker = [];
         this.invalidateDerivedCaches();
     }

🤖 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 `@language-server/src/core/search-engine.ts` around lines 186 - 187, The
clear() method currently doesn't reset the reusable visited state, leaving a
previously large Uint8Array retained; update the clear() implementation to
explicitly reset the visitedBuffer to a new Uint8Array(0) and visitedTracker to
an empty array (visitedBuffer = new Uint8Array(0); visitedTracker = [];),
alongside the existing cache/field resets so the engine truly frees that memory
when clearing state.