fix(codegen): avoid sourcemap panic on `U+2028`/`U+2029` by camc314 · Pull Request #19548 · oxc-project/oxc

camc314 · 2026-02-19T17:01:35Z

camc314 · 2026-02-19T17:01:48Z

fix(codegen): avoid sourcemap panic on U+2028/U+2029 #19548 👈 (View in Graphite)
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Copilot

Pull request overview

Adds regression coverage in the sourcemap builder test suite for JavaScript line-separator characters U+2028 (LS) and U+2029 (PS), which are valid line terminators and previously triggered sourcemap-related panics.

Changes:

Extend add_source_mapping tests to include inputs containing U+2028/U+2029.
Validate generated line/column tracking for LS/PS alone and when surrounded by other characters.

crates/oxc_codegen/src/sourcemap_builder.rs

Copilot · 2026-02-19T17:08:51Z

@camc314 I've opened a new pull request, #19549, to work on those changes. Once the pull request is ready, I'll request review from you.

codspeed-hq · 2026-02-19T17:09:20Z

Merging this PR will not alter performance

✅ 47 untouched benchmarks
⏩ 3 skipped benchmarks¹

_{Comparing c/02-19-fix_codegen_avoid_sourcemap_panic_on_u_2028___u_2029_ (cb59c95) with main (b5fa195)²}

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. ↩
No successful run was found on main (ad43ccc) during the generation of this report, so b5fa195 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

Copilot

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

overlookmotel

I've pushed a commit which reverts most of the changes and just fixes the actual bug with minimum of changes.

The advantage of not introducing a separate line_break_byte_len var is it that increases the chances that all the calculations can be done in registers, without having to spill onto the stack. The most important thing in this hot loop is that the fast paths for ASCII chars and \n remain as streamlined as possible. The code which handles irregular line breaks will rarely be hit, so it's fine to add 1 operation there.

This is a micro-optimization, but as the previous PR which touched this code demonstrated (#13903), this code is very perf-sensitive.

There was one other good change in this PR. I'll split that out into a separate perf PR, with some other small improvements I noticed while reviewing this.

overlookmotel · 2026-02-20T14:21:53Z

@camc314 Please take a look at my changes, and merge if you're happy with it.

camc314

Thanks! - looks good to me

camc314 · 2026-02-20T14:22:35Z

Merge activity

Feb 20, 2:22 PM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Feb 20, 2:22 PM UTC: camc314 added this pull request to the Graphite merge queue.
Feb 20, 2:29 PM UTC: Merged by the Graphite merge queue.

Fixes rolldown/rolldown#8388.

@cam314

Follow-on after #19548. Remove a bounds check from hot loop in `SourcemapBuilder::update_generated_line_and_column` by doing only 1 bounds check to get next 2 bytes, instead of 2 bounds checks for each byte. This optimization was taken from @cam314's original version of PR #19548. While reviewing that PR I also thought I'd spied 2 other optimizations, but on reflection, I realized they were better left as is. Add comments to explain why.

### 🚀 Features - e814049 oxc_data_structure/rope: Add `get_offset_from_line_and_column` (#18133) (Sysix) ### 🐛 Bug Fixes - 7958b56 linter: Fix syntax error reporting in some output formatters. (#19590) (connorshea) - e316694 codegen: Avoid sourcemap panic on `U+2028`/`U+2029` (#19548) (camc314) - 933ff72 semantic: Emit correct error code for reserved type name (#19545) (camc314) ### ⚡ Performance - b5fa195 codegen: Remove bounds check from `SourcemapBuilder` (#19578) (overlookmotel) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>

github-actions bot added the A-codegen Area - Code Generation label Feb 19, 2026

camc314 mentioned this pull request Feb 19, 2026

[Panic]: Sourcemap generation panics with U+2028/U+2029 (LINE/PARAGRAPH SEPARATOR) characters rolldown/rolldown#8388

Closed

github-actions bot added the C-bug Category - Bug label Feb 19, 2026

camc314 marked this pull request as ready for review February 19, 2026 17:02

Copilot AI review requested due to automatic review settings February 19, 2026 17:02

camc314 assigned overlookmotel Feb 19, 2026

Copilot started reviewing on behalf of camc314 February 19, 2026 17:02 View session

camc314 force-pushed the c/02-19-fix_codegen_avoid_sourcemap_panic_on_u_2028___u_2029_ branch from 6ea895a to f2146ad Compare February 19, 2026 17:02

Copilot AI reviewed Feb 19, 2026

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crates/oxc_codegen/src/sourcemap_builder.rs Show resolved Hide resolved

camc314 requested a review from Copilot February 19, 2026 17:08

Copilot AI mentioned this pull request Feb 19, 2026

fix(codegen): verify U+2028/U+2029 sourcemap panic fix is correct #19549

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overlookmotel force-pushed the c/02-19-fix_codegen_avoid_sourcemap_panic_on_u_2028___u_2029_ branch from f2146ad to cb59c95 Compare February 20, 2026 14:12

overlookmotel approved these changes Feb 20, 2026

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overlookmotel assigned camc314 and unassigned overlookmotel Feb 20, 2026

camc314 commented Feb 20, 2026

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camc314 added the 0-merge Merge with Graphite Merge Queue label Feb 20, 2026

fix(codegen): avoid sourcemap panic on U+2028/U+2029 (#19548)

e316694

Fixes rolldown/rolldown#8388.

graphite-app bot force-pushed the c/02-19-fix_codegen_avoid_sourcemap_panic_on_u_2028___u_2029_ branch from cb59c95 to e316694 Compare February 20, 2026 14:23

graphite-app bot merged commit e316694 into main Feb 20, 2026
21 checks passed

graphite-app bot deleted the c/02-19-fix_codegen_avoid_sourcemap_panic_on_u_2028___u_2029_ branch February 20, 2026 14:29

graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Feb 20, 2026

overlookmotel mentioned this pull request Feb 20, 2026

perf(codegen): remove bounds check from SourcemapBuilder #19578

Merged

Boshen mentioned this pull request Feb 23, 2026

release(crates): oxc v0.115.0 #19626

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fix(codegen): avoid sourcemap panic on `U+2028`/`U+2029`#19548

fix(codegen): avoid sourcemap panic on `U+2028`/`U+2029`#19548
graphite-app[bot] merged 1 commit intomainfrom
c/02-19-fix_codegen_avoid_sourcemap_panic_on_u_2028___u_2029_

camc314 commented Feb 19, 2026 •

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Merging this PR will not alter performance

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camc314 commented Feb 19, 2026 •

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