Skip to content

fix: reset the word-boundary state on newline in Hires::Boundary sourcemaps#10025

Merged
graphite-app[bot] merged 1 commit into
mainfrom
06-30-fix_reset_the_word-boundary_state_on_newline_in_hires_boundary_sourcemaps
Jul 2, 2026
Merged

fix: reset the word-boundary state on newline in Hires::Boundary sourcemaps#10025
graphite-app[bot] merged 1 commit into
mainfrom
06-30-fix_reset_the_word-boundary_state_on_newline_in_hires_boundary_sourcemaps

Conversation

@shulaoda

Copy link
Copy Markdown
Member

What this solves

In Hires::Boundary mode the sourcemap builder tracks char_in_hires_boundary so that only the first character of each word run emits a mapping token. A '\n' is handled in its own match arm that bumps the line but never clears that flag. So when a source line ends with a word character (identifier, number, keyword), the flag stays set across the newline, the first word character of the next line takes the "already inside a word" branch and is skipped, and that line gets no start-of-line mapping. For example const a = 1\nconst b = 2 left the second line's leading word unmapped.

Hires::Boundary is used widely (plugin transform sourcemaps, generateMap({ hires: "boundary" }), and the asset-module / copy-module / vite-dynamic-import-vars / vite-import-glob builtins), so this degrades sourcemaps for common no-semicolon and identifier-terminated lines. The reference magic-string runs '\n' through the same boundary logic, which resets the flag, so it does not lose the mapping.

The fix

Reset char_in_hires_boundary to false in the '\n' arm so a newline ends the current word run and the first word character of the next line still emits its boundary token.

Tests

Added hires_boundary_maps_word_at_start_of_next_line in crates/string_wizard/tests/magic_string_source_map.rs: for a source whose first line ends with a word char and whose second line starts with one, it asserts a token maps the start of the second generated line back to the second source line. It fails on the old code and passes with the fix. The existing Hires::Boundary snapshot is unchanged because its lines end with non-word characters.

@netlify

netlify Bot commented Jun 30, 2026

Copy link
Copy Markdown

Deploy Preview for rolldown-rs canceled.

Name Link
🔨 Latest commit f812a7d
🔍 Latest deploy log https://app.netlify.com/projects/rolldown-rs/deploys/6a45df4a069b1600083ea787

@codspeed-hq

codspeed-hq Bot commented Jun 30, 2026

Copy link
Copy Markdown

Merging this PR will not alter performance

✅ 7 untouched benchmarks
⏩ 10 skipped benchmarks1


Comparing 06-30-fix_reset_the_word-boundary_state_on_newline_in_hires_boundary_sourcemaps (8dea337) with main (af38338)

Open in CodSpeed

Footnotes

  1. 10 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.

@shulaoda
shulaoda requested a review from h-a-n-a July 2, 2026 02:49

hyfdev commented Jul 2, 2026

Copy link
Copy Markdown
Member

Merge activity

…cemaps (#10025)

### What this solves

In `Hires::Boundary` mode the sourcemap builder tracks `char_in_hires_boundary` so that only the first character of each word run emits a mapping token. A `'\n'` is handled in its own match arm that bumps the line but never clears that flag. So when a source line ends with a word character (identifier, number, keyword), the flag stays set across the newline, the first word character of the next line takes the "already inside a word" branch and is skipped, and that line gets no start-of-line mapping. For example `const a = 1\nconst b = 2` left the second line's leading word unmapped.

`Hires::Boundary` is used widely (plugin transform sourcemaps, `generateMap({ hires: "boundary" })`, and the asset-module / copy-module / vite-dynamic-import-vars / vite-import-glob builtins), so this degrades sourcemaps for common no-semicolon and identifier-terminated lines. The reference magic-string runs `'\n'` through the same boundary logic, which resets the flag, so it does not lose the mapping.

### The fix

Reset `char_in_hires_boundary` to `false` in the `'\n'` arm so a newline ends the current word run and the first word character of the next line still emits its boundary token.

### Tests

Added `hires_boundary_maps_word_at_start_of_next_line` in `crates/string_wizard/tests/magic_string_source_map.rs`: for a source whose first line ends with a word char and whose second line starts with one, it asserts a token maps the start of the second generated line back to the second source line. It fails on the old code and passes with the fix. The existing `Hires::Boundary` snapshot is unchanged because its lines end with non-word characters.
@graphite-app
graphite-app Bot force-pushed the 06-30-fix_reset_the_word-boundary_state_on_newline_in_hires_boundary_sourcemaps branch from 8dea337 to f812a7d Compare July 2, 2026 03:47
@graphite-app
graphite-app Bot merged commit f812a7d into main Jul 2, 2026
34 checks passed
@graphite-app
graphite-app Bot deleted the 06-30-fix_reset_the_word-boundary_state_on_newline_in_hires_boundary_sourcemaps branch July 2, 2026 03:51
@rolldown-guard rolldown-guard Bot mentioned this pull request Jul 8, 2026
shulaoda added a commit that referenced this pull request Jul 8, 2026
## [1.1.5] - 2026-07-08

### 🚀 Features

- detect top-level import-binding reads as execution-order sensitive (#10180) by @hyf0
- sourcemap_filenames: add a sourcemapFileNames option (#9271) by @V1OL3TF0X
- binding: record plugin hook result kind in tracing spans (#10154) by @IWANABETHATGUY
- linking: skip side-effect-free modules in per-entry reachability (#10111) by @IWANABETHATGUY
- improve error message for unresolved virtual imports (#10156) by @sapphi-red
- add descriptive metadata to plugin API (#10106) by @sapphi-red
- add `--configLoader=native` option (#10118) by @sapphi-red

### 🐛 Bug Fixes

- improve invalid annotation warnings (#10185) by @hyf0
- keep deduplicated asset filenames stable once they can be observed (#10191) by @shulaoda
- sourcemap_filenames: use public option name in pattern errors (#10188) by @IWANABETHATGUY
- sourcemap_filenames: hash prepared sourcemap content (#10178) by @hyf0
- tree-shake unused circular declarators exported via export list (#10166) by @IWANABETHATGUY
- dev: don't panic when an HMR rebuild hits an unresolved import (#10162) by @shulaoda
- propagate errors from output.globals function (#9880) by @shulaoda
- dev: revert cache mutations when a partial scan fails (#10110) by @shulaoda
- dev: update importer relationships of cached modules in incremental build (#10107) by @shulaoda
- hmr: fall back to full reload when a changed module is not registered as executed (#10132) by @shulaoda
- chunk-optimizer: follow entry facade edges in runtime placement cycle check (#10101) by @hyf0
- dev: ignore watcher events after close (#10113) by @hyf0
- emit async wrapper for TLA modules under onDemandWrapping (#10086) by @IWANABETHATGUY
- gate sideEffects:false modules' side effects on body demand (#10080) by @IWANABETHATGUY
- rolldown_plugin_vite_resolve: return empty object for `browser: false` mapped modules (#10082) by @sapphi-red
- reset the word-boundary state on newline in Hires::Boundary sourcemaps (#10025) by @shulaoda
- trim an emptied chunk's outro/intro instead of skipping past it (#10029) by @shulaoda
- test each edited chunk's own start against indent exclude ranges (#10026) by @shulaoda
- preserve sourcemap mappings for indented lines when a CJS module shares the chunk (#10074) by @hyf0

### 🚜 Refactor

- separate tree-shaking side effects from execution order sensitivity (#10168) by @hyf0
- type construct_vite_preload_call to take an ObjectPattern (#10135) by @shulaoda
- treeshake: single-source the own-export classification shared with the lazy-barrel loader (#10098) by @IWANABETHATGUY
- dev: reuse Vite's bundledDev server (#10081) by @h-a-n-a
- clippy: ban std HashMap/HashSet in favour of FxHashMap/FxHashSet (#10108) by @Boshen
- treeshake: make body demand a second module bit instead of a stmt multimap (#10097) by @IWANABETHATGUY
- seal used_symbol_refs by construction after its last writer (#10091) by @hyf0
- treeshake: replace inclusion mutual recursion with a worklist engine (#10096) by @IWANABETHATGUY
- treeshake: split include_statements.rs into focused modules (#10095) by @IWANABETHATGUY
- drop redundant is_user_defined filter on partitioned entries (#10050) by @shulaoda
- project the retained export interface out of used_symbol_refs (#10089) by @hyf0
- track used external symbols separately from used_symbol_refs (#10088) by @hyf0
- make module namespace inclusion an explicit linking metadata field (#10087) by @hyf0
- rename statement evaluation metadata (#10078) by @hyf0

### 📚 Documentation

- virtual modules user-facing id convention (#10155) by @sapphi-red
- cli: clarify disabling boolean/object flags like codeSplitting (#10153) by @IWANABETHATGUY
- chore: remove Vite+ alpha banner (#10105) by @mdong1909
- write down the used_symbol_refs contract (#10090) by @hyf0
- dev/lazy: update design and implementation (#10079) by @h-a-n-a

### ⚡ Performance

- ast_scanner: stop order-sensitivity checks once a module is flagged (#10190) by @IWANABETHATGUY
- return impl ExactSizeIterator from slice-backed accessors (#10133) by @Boshen
- binding: box dev and watcher napi futures (#10103) by @Boshen

### 🧪 Testing

- move string_wizard replace unit tests to the JS magic-string suite (#10176) by @IWANABETHATGUY
- dev: assert incremental scan state matches a fresh full build after each HMR step (#10115) by @shulaoda
- dev: restore runtime assertions of delete_file_not_used_anymore (#10112) by @shulaoda
- dev: fix flaky dev server tests in CI (#10152) by @h-a-n-a
- add regression test for #10099 (lazyBarrel drops default-import binding but keeps its property reads) (#10109) by @IWANABETHATGUY

### ⚙️ Miscellaneous Tasks

- deploy website to Void via GitHub OIDC (#10192) by @Boshen
- deps: update oxc to 0.139.0 (#10161) by @shulaoda
- deps: update test262 submodule for tests (#10160) by @rolldown-guard[bot]
- rolldown_plugin_utils: remove dead asset-url and css scaffolding (#10131) by @shulaoda
- deps: revert vite-plus to v0.2.1 (#10148) by @shulaoda
- deps: update github actions (#10141) by @renovate[bot]
- deps: update dependency rust to v1.96.1 (#10145) by @renovate[bot]
- deps: update npm packages (#10142) by @renovate[bot]
- deps: update rust crates (#10143) by @renovate[bot]
- deps: update napi to v3.10.3 (#10121) by @renovate[bot]
- rolldown_utils: remove unused time module (#10138) by @shulaoda
- remove dead CopyModulePlugin::is_active method (#10129) by @shulaoda
- remove dead LazyCompilationContext::is_lazy_module method (#10128) by @shulaoda
- remove dead BuildDiagnostic::downcast_ref method (#10127) by @shulaoda
- deps: update dependency vite-plus to v0.2.2 (#10084) by @renovate[bot]
- deps: update rust crate oxc_sourcemap to v8.1.0 (#10122) by @renovate[bot]
- deps: update crate-ci/typos action to v1.48.0 (#10124) by @renovate[bot]
- enable more clippy restriction lints (#10114) by @Boshen
- deps: update rust dependencies (#10100) by @Boshen
- deps: update oxc resolver to v11.23.0 (#10083) by @renovate[bot]

### ◀️ Revert

- Revert "chore(deps): revert vite-plus to v0.2.1" (#10157) by @h-a-n-a
- "fix(hmr): fall back to full reload when a changed module is not registered as executed (#10132)" (#10151) by @shulaoda

### ❤️ New Contributors

* @V1OL3TF0X made their first contribution in [#9271](#9271)

Co-authored-by: shulaoda <[email protected]>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

2 participants