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perf(linter/aria-role): remove unnecessary string allocations in run method#22168

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perf(linter/aria-role): remove unnecessary string allocations in run method#22168
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perf/aria-role-remove-string-allocs

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@connorshea

@connorshea connorshea commented May 6, 2026

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This is another micro-optimization to remove some unnecessary memory allocations and get a very minor speed improvement/code improvement. In real codebases this'll be basically impossible to detect, but I figure it's worth it regardless.

Below is Claude's summary.


Summary

  • Remove String::from(str.value.as_str())split_whitespace() works directly on the &str, no heap copy needed.
  • Replace allowed_invalid_roles.contains(&word.to_string()) with .iter().any(|s| s == word) — avoids a String allocation per word comparison.

Benchmark data

Fixture: 20 synthetic JSX files, 40,000 elements with role attributes (mix of valid, invalid, multi-word, and empty roles).

Wall-clock (paired interleaved, N=60)

Baseline Optimized Delta
Rule ON 24.34 ms 22.74 ms -1.61 ms
Parse-only 8.30 ms 8.46 ms -0.16 ms (noise)
  • Paired t-statistic: 7.71 (highly significant, |t| > 2 threshold)
  • Win/Loss/Tie: 49/11/0
  • Parse-only shows no significant difference (t = -1.34), confirming the signal is from the rule change, not binary layout effects.

Hyperfine (unpaired, N=50): optimized ran 1.05 ± 0.07x faster than baseline.

Allocation counts (counting global allocator)

Metric Baseline Optimized Saved Reduction
Alloc count (rule-attributable) 364,208 316,209 47,999 13.2%
Alloc bytes (rule-attributable) 26.6 MB 26.2 MB 434 KB 1.6%

~48,000 fewer heap allocations. The count reduction is large because both the String::from() copy (1 per element) and the .to_string() per word per invalid-role check are eliminated. Byte reduction is modest because the role strings are short.

Test plan

  • cargo test -p oxc_linter aria_role — all tests pass
  • cargo clippy -p oxc_linter --no-deps -- -D warnings — clean
  • just fmt — no changes needed
  • Behavioral parity confirmed (JSON output diff shows only start_time)

🤖 Generated with Claude Code

@github-actions github-actions Bot added the A-linter Area - Linter label May 6, 2026
@connorshea connorshea marked this pull request as ready for review May 6, 2026 04:10
@connorshea connorshea requested a review from camc314 as a code owner May 6, 2026 04:10
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Pull request overview

This PR applies a small performance optimization to the jsx_a11y/aria_role lint rule by eliminating avoidable heap allocations when validating role string literals.

Changes:

  • Avoid allocating an owned String copy of the role attribute value before splitting (split_whitespace() now runs directly on &str).
  • Avoid allocating a String per word when checking allowed_invalid_roles (compare against existing Strings without conversions).

@codspeed-hq

codspeed-hq Bot commented May 6, 2026

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Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 47 skipped benchmarks1


Comparing perf/aria-role-remove-string-allocs (94279c9) with main (c9ce045)

Open in CodSpeed

Footnotes

  1. 47 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.

@camchenry camchenry added the 0-merge Merge with Graphite Merge Queue label May 6, 2026

camchenry commented May 6, 2026

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…method (#22168)

This is another micro-optimization to remove some unnecessary memory allocations and get a very minor speed improvement/code improvement. In real codebases this'll be basically impossible to detect, but I figure it's worth it regardless.

Below is Claude's summary.

---

## Summary

- Remove `String::from(str.value.as_str())` — `split_whitespace()` works directly on the `&str`, no heap copy needed.
- Replace `allowed_invalid_roles.contains(&word.to_string())` with `.iter().any(|s| s == word)` — avoids a `String` allocation per word comparison.

## Benchmark data

Fixture: 20 synthetic JSX files, 40,000 elements with `role` attributes (mix of valid, invalid, multi-word, and empty roles).

### Wall-clock (paired interleaved, N=60)

| | Baseline | Optimized | Delta |
|---|---|---|---|
| Rule ON | 24.34 ms | 22.74 ms | **-1.61 ms** |
| Parse-only | 8.30 ms | 8.46 ms | -0.16 ms (noise) |

- Paired t-statistic: **7.71** (highly significant, |t| > 2 threshold)
- Win/Loss/Tie: **49/11/0**
- Parse-only shows no significant difference (t = -1.34), confirming the signal is from the rule change, not binary layout effects.

Hyperfine (unpaired, N=50): optimized ran **1.05 ± 0.07x** faster than baseline.

### Allocation counts (counting global allocator)

| Metric | Baseline | Optimized | Saved | Reduction |
|---|---|---|---|---|
| Alloc count (rule-attributable) | 364,208 | 316,209 | **47,999** | **13.2%** |
| Alloc bytes (rule-attributable) | 26.6 MB | 26.2 MB | **434 KB** | **1.6%** |

~48,000 fewer heap allocations. The count reduction is large because both the `String::from()` copy (1 per element) and the `.to_string()` per word per invalid-role check are eliminated. Byte reduction is modest because the role strings are short.

## Test plan

- [x] `cargo test -p oxc_linter aria_role` — all tests pass
- [x] `cargo clippy -p oxc_linter --no-deps -- -D warnings` — clean
- [x] `just fmt` — no changes needed
- [x] Behavioral parity confirmed (JSON output diff shows only `start_time`)

🤖 Generated with [Claude Code](https://claude.com/claude-code)
@graphite-app graphite-app Bot force-pushed the perf/aria-role-remove-string-allocs branch from 94279c9 to 26fa2fc Compare May 6, 2026 04:18
@graphite-app graphite-app Bot merged commit 26fa2fc into main May 6, 2026
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@graphite-app graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label May 6, 2026
@graphite-app graphite-app Bot deleted the perf/aria-role-remove-string-allocs branch May 6, 2026 04:23
graphite-app Bot pushed a commit that referenced this pull request May 6, 2026
…h rfind (#22172)

Another minor optimization + code simplification. Claude's summary is below. As with all of these, the benchmark is based on running the rule on a file with a lot of specific code that isn't likely to occur in real codebases. So the % drops shouldn't be seen as representative of much beyond "this specific code path is faster".

---

## Summary

Two allocations per `@property` JSDoc tag with a dot — the `Vec<&str>` from `split + collect` and the `String` from `join(".")` — collapse to a single slice index using `rfind('.')`.

```rust
// before
if type_name.contains('.') {
    let mut parts = type_name.split('.').collect::<Vec<_>>();
    parts.pop();                                // `foo[].bar` -> `foo[]`
    let parent_name = parts.join(".");
    let parent_name = parent_name.trim_end_matches("[]");
    ...
}

// after
if let Some(dot_idx) = type_name.rfind('.') {
    let parent_name = type_name[..dot_idx].trim_end_matches("[]");  // `foo[].bar` -> `foo[]` -> `foo`
    ...
}
```

`rfind('.')` matches the last dot; the original `split + pop + join` reassembled all-but-the-last segment with `.` as the separator — equivalent.

Same family as #22164/#22166/#22167/#22168.

## Benchmark

Synthetic fixture: 30 JS files × 60 typedef blocks × 16 `@property` tags ≈ **28,800 tags**, ~80% with dots. Counting global allocator (system alloc, no mimalloc) on the rule-on and parse-only configs; rule-attributable = total − parse-only.

### Wall-clock (paired interleaved, N=60)

| | Baseline | Optimized | Δ |
|---|---|---|---|
| Rule ON | 21.564 ms | 20.550 ms | **−1.014 ms** |
| Parse-only | 7.319 ms | 7.326 ms | +0.007 ms (noise) |

- Paired t-stat: **5.02** (rule-on); **−0.05** (parse-only control)
- Win/Loss/Tie: **42 / 18 / 0**
- Parse-only is flat, so the delta isn't a binary-layout artifact.

### Allocations (rule-attributable)

| Metric | Baseline | Optimized | Saved | Reduction |
|---|---|---|---|---|
| Count | 318,002 | 282,603 | **35,399** | **11.1%** |
| Bytes | 30.7 MB | 29.4 MB | **1.32 MB** | **4.3%** |

Saves ~1.5 allocations per dotted tag on this fixture (Vec is sometimes elided when the path is `a.b`, but `String` from `join` always allocates).

## Test plan

- [x] `cargo test -p oxc_linter --lib jsdoc::check_property_names` — passes
- [x] `--format=json` parity confirmed across baseline and optimized binaries on the fixture (only `start_time` differs)
- [x] Parse-only control confirms no binary-layout effect (t = −0.05)
- [x] `just fmt` clean

🤖 Generated with [Claude Code](https://claude.com/claude-code)
camc314 added a commit that referenced this pull request May 11, 2026
# Oxlint
### 💥 BREAKING CHANGES

- 00ce512 oxlint/lsp: [**BREAKING**] Don't fix suggestions on fixAll
code actions & command (#22195) (Sysix)

### 🚀 Features

- 0eeceaf linter/no-unused-vars: Rename parameter with initializer
(#22308) (camc314)
- fa0232b linter/no-unused-vars: Add param rename suggestion (#22285)
(Ryota Misumi)
- ae59305 linter/promise/no-promise-in-callback: Add
`exemptDeclarations` option (#22275) (Mikhail Baev)
- 60bed4a linter: Extends `no-redundant-roles` and
`prefer-tag-over-role` support roles (#22069) (mehm8128)
- 545c80f linter/eslint: Implement `prefer-regex-literals` rule (#22192)
(Mikhail Baev)
- cf86d7a linter: Bulk suppression (#19328) (Said Atrahouch)
- 23abd22 linter/jsx-a11y: Implement
no-noninteractive-element-to-interactive-role (#21264) (Pedro Tainha)
- fbb8f22 linter: Support `ignores` in overrides (#22148) (camc314)
- 5a4414d oxlint/lsp: Support `rulesCustomization` lsp option (#21858)
(Sysix)

### 🐛 Bug Fixes

- 610f4c7 linter/no-unused-vars: Avoid renaming captured vars (#22310)
(camc314)
- 6b50f23 oxlint/cli: Load root config by searching up parent
directories (#22272) (Sysix)
- 31a5de7 linter: Rename override `ignores` to `excludeFiles` (#22283)
(camc314)
- 26d5d7b linter: Add missing vitest/valid-describe-callback
functionality (#22279) (camchenry)
- 784530f linter: `valid-title`: detect `String.raw` strings (#22271)
(Sysix)
- 080d90e linter: Move `no-debugger` fix to suggestion (#22256) (Sysix)
- 25b7017 linter: Undocument override `ignores` option (#22213)
(camc314)
- 7bb00dd linter: Fix role-has-required-aria-props (#22097) (mehm8128)
- d25279e linter/disable-directives: Improve parsing of names,
descriptions (#22184) (camc314)
- a59e447 linter/disable-directives: Ignore invalid enable suffixes
(#22179) (camc314)
- aafef0f ci: Disable bulk supression test on big endian (#22175)
(camc314)
- 281daec linter/vue/define-props-destructuring: Add
`only-when-assigned` config opt (#22142) (camc314)
- 46ab679 linter/plugins: Trim leading newline for partial sources
(#20928) (bab)
- 29ff6d9 linter: Update docs for no_alias_methods rule to be
Vitest-specific and add toThrowError alias (#22129) (camchenry)

### ⚡ Performance

- 9414bee linter/role-has-required-aria-props: Avoid intermediate vec
(#22212) (camc314)
- 3883ea3 linter/no-useless-escape: Drop unnecessary Vec collect
(#22171) (connorshea)
- 42c3029 linter/check-property-names: Replace split-collect-pop-join
with rfind (#22172) (connorshea)
- 9551d53 linter: Remove unnecessary Vec collect in CFG edge traversal
(#22167) (connorshea)
- 26fa2fc linter/aria-role: Remove unnecessary string allocations in run
method (#22168) (connorshea)
- c9ce045 linter/getter-return: Remove unnecessary Vec collect in CFG
edge traversal (#22166) (connorshea)
- 72bd846 linter/no-this-in-sfc: Reorder cheap name check, avoid String
allocation (#22164) (connorshea)

### 📚 Documentation

- 4da212a linter/no-unused-vars: Add docs to
`rename_unused_function_parameter` (#22311) (camc314)
- 27c4628 linter/forbid-dom-props: Escape jsx examples in lint rule docs
(#22254) (4MBL)
- 3f81147 linter: Improve the `react/jsx-key` rule docs. (#22162)
(connorshea)
- 07f03cc linter/consistent-return: Add note about `noImplicitReturns`
coverage (#22156) (camc314)
- 7c1e049 oxlint/lsp: Improve autogenerated lsp docs (#22154) (Sysix)
- 87b3e38 linter: Update docs to be vitest-specific for
consistent-test-it (#22128) (camchenry)
# Oxfmt
### 💥 BREAKING CHANGES

- 5c6c390 oxfmt: [**BREAKING**] Respect more git ignore options, align
with Oxlint (#22210) (leaysgur)

### 🚀 Features

- 6e8e818 oxfmt: Experimental .svelte support (#21700) (leaysgur)

### 🐛 Bug Fixes

- e2a20b6 formatter: Add space after commas in import attributes
(#22274) (Leonabcd123)

### ⚡ Performance

- b756682 oxfmt: Optimize nested config prescan (#22232) (Jovi De
Croock)
- f14e81e formatter/sort_imports: Skip sort for single import runs
(#22204) (leaysgur)
- 32255b1 formatter: Process `ImportDeclaration`s in a run (#22079)
(overlookmotel)

### 📚 Documentation

- 4da6f4c formatter: Correct comment (#22217) (overlookmotel)
- ef3507d formatter/sort_imports: Refresh docs (#22203) (leaysgur)

Co-authored-by: Cameron <cameron.clark@hey.com>
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