perf(formatter): reduce the size of `TextWidth` to 4 byte by Dunqing · Pull Request #15827 · oxc-project/oxc

Dunqing · 2025-11-18T03:07:06Z

close: formatter: Size assertion is not satisfied for --target wasm32-wasip1-threads #15823

The size of TextWidth was increased in #15762, which caused a 2% performance regression; I am unsure why this occurred at the time. Now I understand that the TextWidth size increased from 4 bytes to 8 bytes, which caused the FormatElement enum size to become 24 bytes in a 32-bit system.

This PR changes the TextWidth enum to a struct that only stores a u32 width and uses the 31st bit as a marker to represent whether it is a multiline or not. Although it is smaller than NonZeroU32, it is enough to store the text width.

Dunqing · 2025-11-18T03:07:22Z

perf(formatter): reduce the size of TextWidth to 4 byte #15827 👈 (View in Graphite)
main

How to use the Graphite Merge Queue

Add either label to this PR to merge it via the merge queue:

0-merge - adds this PR to the back of the merge queue
hotfix - for urgent hot fixes, skip the queue and merge this PR next

You must have a Graphite account in order to use the merge queue. Sign up using this link.

_{An organization admin has enabled the Graphite Merge Queue in this repository.} _{Please do not merge from GitHub as this will restart CI on PRs being processed by the merge queue.}

This stack of pull requests is managed by Graphite. Learn more about stacking.

codspeed-hq · 2025-11-18T03:11:46Z

CodSpeed Performance Report

Merging #15827 will not alter performance

_{Comparing 11-18-perf_formatter_reduce_the_size_of_textwidth_to_4_byte (bfbacd8) with main (e346426)}

Summary

✅ 38 untouched
⏩ 7 skipped¹

7 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. ↩

Copilot

Pull Request Overview

This PR optimizes the TextWidth type to reduce memory footprint from 8 bytes to 4 bytes, addressing a 2% performance regression. The optimization uses bit-packing to store both the width value and a multiline flag in a single u32, rather than using an enum with NonZeroU32.

Key Changes:

Replaced TextWidth enum (with Width and Multiline variants) with a struct using bit 31 as a multiline flag and bits 0-30 for width
Refactored pattern matching in printer code to use is_multiline() method instead of enum variants
Added comprehensive test coverage for the new bit-manipulation logic

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
`crates/oxc_formatter/src/formatter/format_element/mod.rs`	Reimplemented `TextWidth` as a struct with bit-packing, removed `Width` type and `NonZeroU32` dependency, added test suite
`crates/oxc_formatter/src/formatter/printer/mod.rs`	Refactored pattern matching from enum variants to `is_multiline()` method calls in both `Printer` and `FitsMeasurer`

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

leaysgur · 2025-11-19T05:13:43Z

I'll fix clippy and merge.

leaysgur · 2025-11-19T05:14:04Z

Merge activity

Nov 19, 5:14 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Nov 19, 5:20 AM UTC: leaysgur added this pull request to the Graphite merge queue.
Nov 19, 5:26 AM UTC: Merged by the Graphite merge queue.

* close: #15823 The size of `TextWidth` was increased in #15762, which caused a 2% performance regression; I am unsure why this occurred at the time. Now I understand that the `TextWidth` size increased from 4 bytes to 8 bytes, which caused the FormatElement enum size to become 24 bytes in a 32-bit system. This PR changes the `TextWidth` enum to a struct that only stores a `u32` width and uses the 31st bit as a marker to represent whether it is a multiline or not. Although it is smaller than `NonZeroU32`, it is enough to store the text width.

# Oxlint ### 💥 BREAKING CHANGES - cbb27fd ast: [**BREAKING**] Add `TSGlobalDeclaration` type (#15712) (overlookmotel) ### 🚀 Features - 72660f7 linter: Support auto generate config document for tuple lint option (#15904) (Duc Nghiem Xuan) - 0c1f82b linter/plugins: Add `tokens` property to `Program` (#16020) (overlookmotel) - 9e61beb linter/plugins: Implement `SourceCode#getFirstToken()` (#16002) (Arsh) - 9a548dd linter/plugins: Implement `SourceCode#getLastTokens()` (#16000) (Arsh) - 0b6cb11 linter/plugins: Implement `SourceCode#getFirstTokens()` (#15976) (Arsh) - 166781e linter/plugins: Implement `SourceCode#getTokenAfter()` (#15973) (Arsh) - 6ae232b linter: Expose type errors via tsgolint (#15917) (camc314) - 2bfdd26 linter/plugins: Implement `SourceCode#getTokensAfter()` (#15971) (Arsh) - 45fffc1 linter/plugins: Implement `SourceCode#getTokenBefore()` (#15956) (Arsh) - 776e473 linter/plugins: Implement `SourceCode#getTokensBefore()` (#15955) (Arsh) - 595867a oxlint: Generate markdownDescription fields for oxlint JSON schema. (#15959) (connorshea) - 5569317 vscode: Add quick actions to status bar tooltip (#15962) (Sysix) - 986cac1 linter/plugins: Token-related `SourceCode` APIs (TS ESLint implementation) (#15861) (Arsh) - a21f9e4 linter: Implement unicorn/prefer-bigint-literals rule (#15923) (Michiel Vrins) - 4b9d8d2 linter/type-aware: Include range with tsconfig diagnostics (#15916) (camc314) - 220d01e editor: Improve the status bar item for the VS Code extension by adding a tooltip. (#15819) (connorshea) ### 🐛 Bug Fixes - 2bd3cb6 apps, editors, napi: Fix `oxlint-disable` comments (#16014) (overlookmotel) - 81f5360 linter/prefer-number-properties: Get fixer to replace entire call expr (#15979) (camc314) - e4ba07f language_server: Always write to memory file system (#15975) (Sysix) - a8a2032 linter: Support missing `range` for internal diagnostics (#15964) (camc314) - 619a226 oxlint/lsp: Don't register `textDocument/formatting` capability (#15882) (Sysix) - 6ab1a20 linter: Fix no_useless_spread producing invalid syntax when removing empty object spreads (#15905) (camc314) - be4b6df linter: Unicorn/prefer-string-replace-all incorrectly escapes backslashes (#15901) (camc314) - 9fa9ef2 linter: Gracefully fail when using import plugin, large file counf and JS plugins (#15864) (camc314) - c027398 linter/plugins: Correct bindings package names glob in TSDown config (#15871) (overlookmotel) - b622ef8 linter: Fix `oxc/bad_array_method_on_arguments` rule behavior. (#15854) (connorshea) - aa06c3f linter: Recognize NewExpression as value context in no-unused-private-class-members (#15843) (camc314) - e89c5ba typescript/prefer-namespace-keyword: Skip nested `TSModuleDeclaration`s (#15806) (overlookmotel) - 646d020 linter/exhaustive-dependencies: Prevent is_callee_of_call_expr flag from leaking into nested expressions (#15832) (camc314) - 46bd6bd linter/plugins: Pin `@typescript-eslint/scope-manager` dependency (#15807) (overlookmotel) - fba31fa linter: Patch `@typescript-eslint/scope manager` (#15214) (Arsh) - 50307c1 linter/jest: Ignore `expect` identifier in argument position (#15785) (camc314) ### ⚡ Performance - 024b48a linter/plugins: Lazy-load tokens parsing code (#16011) (overlookmotel) - 15365c9 linter/plugins: Reduce var assignments (#15953) (overlookmotel) - 84d1f4f linter/plugins: Downgrade some checks to debug-only (#15922) (overlookmotel) - a49f704 linter/typescript: Avoid searching source text unless required (#15805) (overlookmotel) ### 📚 Documentation - ceffa5a linter: Add config option docs for various rules. (#16024) (connorshea) - 9a0ed13 linter: Fix config option docs for eslint/operator-assignment rule. (#16030) (connorshea) - 0b18005 linter: Add config docs generation for rules with Regex arguments (#15978) (connorshea) - 48d18e0 linter: Improve diagnostic message for promise/catch-or-return rule (#15980) (connorshea) - 6c72e84 linter: Use backticks for code elements across more rule diagnostics (#15958) (connorshea) - a63dad7 linter/plugins: Add comment (#15952) (overlookmotel) - 81ea642 vscode: Use markdownDescription for better formatting in VSCode Settings (#15889) (connorshea) - db6a110 linter/plugins: Fix JSDoc comment (#15884) (overlookmotel) - 1487271 linter: Add config option docs for `jsdoc/require-param` and `jsdoc/require-returns` rules (#15857) (connorshea) - fbf0fd4 linter/plugins: Add JSDoc comments to `Plugin` and `Rule` types (#15815) (overlookmotel) - ac5e4b5 linter/plugins: Add JSDoc comments and improve comments (#15814) (overlookmotel) - 9b7b083 linter: Fix error in `curly` `"all"` example (#15801) (camc314) - 65a3520 linter: Improve diagnostic for consistent-type-definitions rule. (#15752) (connorshea) ### 🛡️ Security - f9b9276 deps: Update dependency rolldown to v1.0.0-beta.51 (#15856) (renovate[bot]) # Oxfmt ### 💥 BREAKING CHANGES - a937890 formatter: [**BREAKING**] Default to `lineWidth: 100` (#15933) (leaysgur) - 03d5f5a formatter/sort-imports: [**BREAKING**] Change default order to `natural` with `natord` crate (#15828) (leaysgur) - cbb27fd ast: [**BREAKING**] Add `TSGlobalDeclaration` type (#15712) (overlookmotel) ### 🚀 Features - 7818e22 formatter/sort-imports: Support `options.groups` (#15831) (leaysgur) - f9a502c oxfmt: `oxfmt --lsp` support (#15765) (leaysgur) ### 🐛 Bug Fixes - 4817486 formatter: Revert `FormatElement::BestFitting` printing logic (#16028) (Dunqing) - 5562dd6 formatter: Incorrect formatting method chain with trailing comments (#16027) (Dunqing) - 6d14c8b formatter: Comments in export class decorators are printing incorrectly (#15897) (Dunqing) - 683c764 formatter: Correct a few minor mismatched typescript tests (#15894) (Dunqing) - c11cc07 formatter: Improve formatting for default type on type parameters (#15893) (Dunqing) - 0bff596 formatter: Handle JSX expresssion dangling comment (#15890) (leaysgur) - 16a9dc8 formatter: Inconsistent printing of class extends and interface extends (#15892) (Dunqing) - 300b496 formatter: Inconsistent CallExpression and NewExpression around member chain and logical expression (#15858) (Dunqing) ### ⚡ Performance - 65174cc formatter: Reduce the size of `TextWidth` to 4 byte (#15827) (Dunqing) - 4fe3aac formatter: Use `ArenaVec` and `ArenaBox` (#15420) (Dunqing) Co-authored-by: overlookmotel <[email protected]>

…t#15827) * close: oxc-project#15823 The size of `TextWidth` was increased in oxc-project#15762, which caused a 2% performance regression; I am unsure why this occurred at the time. Now I understand that the `TextWidth` size increased from 4 bytes to 8 bytes, which caused the FormatElement enum size to become 24 bytes in a 32-bit system. This PR changes the `TextWidth` enum to a struct that only stores a `u32` width and uses the 31st bit as a marker to represent whether it is a multiline or not. Although it is smaller than `NonZeroU32`, it is enough to store the text width.

# Oxlint ### 💥 BREAKING CHANGES - cbb27fd ast: [**BREAKING**] Add `TSGlobalDeclaration` type (oxc-project#15712) (overlookmotel) ### 🚀 Features - 72660f7 linter: Support auto generate config document for tuple lint option (oxc-project#15904) (Duc Nghiem Xuan) - 0c1f82b linter/plugins: Add `tokens` property to `Program` (oxc-project#16020) (overlookmotel) - 9e61beb linter/plugins: Implement `SourceCode#getFirstToken()` (oxc-project#16002) (Arsh) - 9a548dd linter/plugins: Implement `SourceCode#getLastTokens()` (oxc-project#16000) (Arsh) - 0b6cb11 linter/plugins: Implement `SourceCode#getFirstTokens()` (oxc-project#15976) (Arsh) - 166781e linter/plugins: Implement `SourceCode#getTokenAfter()` (oxc-project#15973) (Arsh) - 6ae232b linter: Expose type errors via tsgolint (oxc-project#15917) (camc314) - 2bfdd26 linter/plugins: Implement `SourceCode#getTokensAfter()` (oxc-project#15971) (Arsh) - 45fffc1 linter/plugins: Implement `SourceCode#getTokenBefore()` (oxc-project#15956) (Arsh) - 776e473 linter/plugins: Implement `SourceCode#getTokensBefore()` (oxc-project#15955) (Arsh) - 595867a oxlint: Generate markdownDescription fields for oxlint JSON schema. (oxc-project#15959) (connorshea) - 5569317 vscode: Add quick actions to status bar tooltip (oxc-project#15962) (Sysix) - 986cac1 linter/plugins: Token-related `SourceCode` APIs (TS ESLint implementation) (oxc-project#15861) (Arsh) - a21f9e4 linter: Implement unicorn/prefer-bigint-literals rule (oxc-project#15923) (Michiel Vrins) - 4b9d8d2 linter/type-aware: Include range with tsconfig diagnostics (oxc-project#15916) (camc314) - 220d01e editor: Improve the status bar item for the VS Code extension by adding a tooltip. (oxc-project#15819) (connorshea) ### 🐛 Bug Fixes - 2bd3cb6 apps, editors, napi: Fix `oxlint-disable` comments (oxc-project#16014) (overlookmotel) - 81f5360 linter/prefer-number-properties: Get fixer to replace entire call expr (oxc-project#15979) (camc314) - e4ba07f language_server: Always write to memory file system (oxc-project#15975) (Sysix) - a8a2032 linter: Support missing `range` for internal diagnostics (oxc-project#15964) (camc314) - 619a226 oxlint/lsp: Don't register `textDocument/formatting` capability (oxc-project#15882) (Sysix) - 6ab1a20 linter: Fix no_useless_spread producing invalid syntax when removing empty object spreads (oxc-project#15905) (camc314) - be4b6df linter: Unicorn/prefer-string-replace-all incorrectly escapes backslashes (oxc-project#15901) (camc314) - 9fa9ef2 linter: Gracefully fail when using import plugin, large file counf and JS plugins (oxc-project#15864) (camc314) - c027398 linter/plugins: Correct bindings package names glob in TSDown config (oxc-project#15871) (overlookmotel) - b622ef8 linter: Fix `oxc/bad_array_method_on_arguments` rule behavior. (oxc-project#15854) (connorshea) - aa06c3f linter: Recognize NewExpression as value context in no-unused-private-class-members (oxc-project#15843) (camc314) - e89c5ba typescript/prefer-namespace-keyword: Skip nested `TSModuleDeclaration`s (oxc-project#15806) (overlookmotel) - 646d020 linter/exhaustive-dependencies: Prevent is_callee_of_call_expr flag from leaking into nested expressions (oxc-project#15832) (camc314) - 46bd6bd linter/plugins: Pin `@typescript-eslint/scope-manager` dependency (oxc-project#15807) (overlookmotel) - fba31fa linter: Patch `@typescript-eslint/scope manager` (oxc-project#15214) (Arsh) - 50307c1 linter/jest: Ignore `expect` identifier in argument position (oxc-project#15785) (camc314) ### ⚡ Performance - 024b48a linter/plugins: Lazy-load tokens parsing code (oxc-project#16011) (overlookmotel) - 15365c9 linter/plugins: Reduce var assignments (oxc-project#15953) (overlookmotel) - 84d1f4f linter/plugins: Downgrade some checks to debug-only (oxc-project#15922) (overlookmotel) - a49f704 linter/typescript: Avoid searching source text unless required (oxc-project#15805) (overlookmotel) ### 📚 Documentation - ceffa5a linter: Add config option docs for various rules. (oxc-project#16024) (connorshea) - 9a0ed13 linter: Fix config option docs for eslint/operator-assignment rule. (oxc-project#16030) (connorshea) - 0b18005 linter: Add config docs generation for rules with Regex arguments (oxc-project#15978) (connorshea) - 48d18e0 linter: Improve diagnostic message for promise/catch-or-return rule (oxc-project#15980) (connorshea) - 6c72e84 linter: Use backticks for code elements across more rule diagnostics (oxc-project#15958) (connorshea) - a63dad7 linter/plugins: Add comment (oxc-project#15952) (overlookmotel) - 81ea642 vscode: Use markdownDescription for better formatting in VSCode Settings (oxc-project#15889) (connorshea) - db6a110 linter/plugins: Fix JSDoc comment (oxc-project#15884) (overlookmotel) - 1487271 linter: Add config option docs for `jsdoc/require-param` and `jsdoc/require-returns` rules (oxc-project#15857) (connorshea) - fbf0fd4 linter/plugins: Add JSDoc comments to `Plugin` and `Rule` types (oxc-project#15815) (overlookmotel) - ac5e4b5 linter/plugins: Add JSDoc comments and improve comments (oxc-project#15814) (overlookmotel) - 9b7b083 linter: Fix error in `curly` `"all"` example (oxc-project#15801) (camc314) - 65a3520 linter: Improve diagnostic for consistent-type-definitions rule. (oxc-project#15752) (connorshea) ### 🛡️ Security - f9b9276 deps: Update dependency rolldown to v1.0.0-beta.51 (oxc-project#15856) (renovate[bot]) # Oxfmt ### 💥 BREAKING CHANGES - a937890 formatter: [**BREAKING**] Default to `lineWidth: 100` (oxc-project#15933) (leaysgur) - 03d5f5a formatter/sort-imports: [**BREAKING**] Change default order to `natural` with `natord` crate (oxc-project#15828) (leaysgur) - cbb27fd ast: [**BREAKING**] Add `TSGlobalDeclaration` type (oxc-project#15712) (overlookmotel) ### 🚀 Features - 7818e22 formatter/sort-imports: Support `options.groups` (oxc-project#15831) (leaysgur) - f9a502c oxfmt: `oxfmt --lsp` support (oxc-project#15765) (leaysgur) ### 🐛 Bug Fixes - 4817486 formatter: Revert `FormatElement::BestFitting` printing logic (oxc-project#16028) (Dunqing) - 5562dd6 formatter: Incorrect formatting method chain with trailing comments (oxc-project#16027) (Dunqing) - 6d14c8b formatter: Comments in export class decorators are printing incorrectly (oxc-project#15897) (Dunqing) - 683c764 formatter: Correct a few minor mismatched typescript tests (oxc-project#15894) (Dunqing) - c11cc07 formatter: Improve formatting for default type on type parameters (oxc-project#15893) (Dunqing) - 0bff596 formatter: Handle JSX expresssion dangling comment (oxc-project#15890) (leaysgur) - 16a9dc8 formatter: Inconsistent printing of class extends and interface extends (oxc-project#15892) (Dunqing) - 300b496 formatter: Inconsistent CallExpression and NewExpression around member chain and logical expression (oxc-project#15858) (Dunqing) ### ⚡ Performance - 65174cc formatter: Reduce the size of `TextWidth` to 4 byte (oxc-project#15827) (Dunqing) - 4fe3aac formatter: Use `ArenaVec` and `ArenaBox` (oxc-project#15420) (Dunqing) Co-authored-by: overlookmotel <[email protected]>

github-actions bot added A-formatter Area - Formatter C-performance Category - Solution not expected to change functional behavior, only performance labels Nov 18, 2025

Dunqing force-pushed the 11-18-perf_formatter_reduce_the_size_of_textwidth_to_4_byte branch 3 times, most recently from 671b8f0 to 7f052b9 Compare November 19, 2025 03:43

Dunqing marked this pull request as ready for review November 19, 2025 03:59

Copilot AI review requested due to automatic review settings November 19, 2025 03:59

Copilot started reviewing on behalf of Dunqing November 19, 2025 03:59 View session

Dunqing requested a review from leaysgur November 19, 2025 04:00

Dunqing assigned leaysgur Nov 19, 2025

Dunqing force-pushed the 11-18-perf_formatter_reduce_the_size_of_textwidth_to_4_byte branch from 7f052b9 to 888c248 Compare November 19, 2025 04:00

Copilot finished reviewing on behalf of Dunqing November 19, 2025 04:02

Copilot AI reviewed Nov 19, 2025

View reviewed changes

leaysgur added the 0-merge Merge with Graphite Merge Queue label Nov 19, 2025

leaysgur approved these changes Nov 19, 2025

View reviewed changes

graphite-app bot force-pushed the 11-18-perf_formatter_reduce_the_size_of_textwidth_to_4_byte branch from bfbacd8 to 65174cc Compare November 19, 2025 05:20

graphite-app bot merged commit 65174cc into main Nov 19, 2025
20 checks passed

graphite-app bot deleted the 11-18-perf_formatter_reduce_the_size_of_textwidth_to_4_byte branch November 19, 2025 05:26

graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Nov 19, 2025

leaysgur mentioned this pull request Nov 19, 2025

formatter: Size assertion is not satisfied for --target wasm32-wasip1-threads #15823

Closed

camc314 mentioned this pull request Nov 23, 2025

evaluation panicked: FormatElement size exceeds 24 bytes when building oxlint version 1.29.0 on 32-bit x86 GNU/Linux #15984

Closed

This was referenced Nov 24, 2025

release(apps): oxlint v1.30.0 && oxfmt v0.15.0 #16039

Closed

release(apps): oxlint v1.30.0 && oxfmt v0.15.0 #16047

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Comments

perf(formatter): reduce the size of `TextWidth` to 4 byte#15827

perf(formatter): reduce the size of `TextWidth` to 4 byte#15827
graphite-app[bot] merged 1 commit intomainfrom
11-18-perf_formatter_reduce_the_size_of_textwidth_to_4_byte

Dunqing commented Nov 18, 2025 •

edited

Loading

Uh oh!

Dunqing commented Nov 18, 2025

Uh oh!

codspeed-hq bot commented Nov 18, 2025 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

leaysgur commented Nov 19, 2025

Uh oh!

leaysgur commented Nov 19, 2025 •

edited by graphite-app bot

Loading

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Uh oh!

Comments

Conversation

Dunqing commented Nov 18, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Dunqing commented Nov 18, 2025

How to use the Graphite Merge Queue

Uh oh!

codspeed-hq bot commented Nov 18, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

CodSpeed Performance Report

Merging #15827 will not alter performance

Summary

Footnotes

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull Request Overview

Reviewed Changes

Uh oh!

leaysgur commented Nov 19, 2025

Uh oh!

leaysgur commented Nov 19, 2025 • edited by graphite-app bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Merge activity

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Dunqing commented Nov 18, 2025 •

edited

Loading

codspeed-hq bot commented Nov 18, 2025 •

edited

Loading

leaysgur commented Nov 19, 2025 •

edited by graphite-app bot

Loading