fix(transformer): propagate source spans for sourcemap correctness by Boshen · Pull Request #19258 · oxc-project/oxc

Boshen · 2026-02-11T11:19:13Z

Summary

Propagate original source node spans to their outermost transformed replacements across all transformer plugins
Codegen skips sourcemap entries for nodes with empty spans (SPAN), so transformed nodes previously produced no sourcemap mappings
Updated 20 files across typescript, jsx, es2016-es2026, class properties, and shared utility functions
Added span: Span parameters to shared helpers (create_assignment, create_member_callee, create_prototype_member) and threaded spans through call chains
Kept SPAN for truly synthetic nodes (generated temps, helper function internals, protocol boilerplate)

🤖 Generated with Claude Code

codspeed-hq · 2026-02-11T11:26:45Z

Merging this PR will not alter performance

✅ 47 untouched benchmarks
⏩ 3 skipped benchmarks¹

_{Comparing fix/transformer-sourcemap-spans (941bc03) with main (740a009)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 (9195430) during the generation of this report, so 740a009 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

Boshen · 2026-02-11T11:33:41Z

Merge activity

Feb 11, 11:33 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Feb 11, 11:33 AM UTC: Boshen added this pull request to the Graphite merge queue.
Feb 11, 11:40 AM UTC: Merged by the Graphite merge queue.

…19258) ## Summary - Propagate original source node spans to their outermost transformed replacements across all transformer plugins - Codegen skips sourcemap entries for nodes with empty spans (`SPAN`), so transformed nodes previously produced no sourcemap mappings - Updated 20 files across typescript, jsx, es2016-es2026, class properties, and shared utility functions - Added `span: Span` parameters to shared helpers (`create_assignment`, `create_member_callee`, `create_prototype_member`) and threaded spans through call chains - Kept `SPAN` for truly synthetic nodes (generated temps, helper function internals, protocol boilerplate) 🤖 Generated with [Claude Code](https://claude.com/claude-code)

Copilot

Pull request overview

This PR improves sourcemap correctness by propagating original source spans onto transformed AST nodes (instead of leaving SPAN), so codegen emits mappings for transformed output across multiple transformer passes.

Changes:

Thread Span through shared AST builder helpers (e.g. member callee/prototype member/assignment) and update call sites.
Update several transformers (TypeScript namespace/enum, JSX refresh/runtime, optional chaining, object rest/spread, async transforms, etc.) to stamp transformed nodes with the originating span.
Preserve SPAN for intentionally synthetic nodes while ensuring outermost replacements carry real spans.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
crates/oxc_transformer/src/utils/ast_builder.rs	Adds `span` plumbing to shared AST construction helpers so callers can preserve source mappings.
crates/oxc_transformer/src/typescript/namespace.rs	Uses namespace node spans for generated declarations/exports and function wrappers.
crates/oxc_transformer/src/typescript/enum.rs	Propagates enum/enum-member spans into generated IIFE/calls/assignments.
crates/oxc_transformer/src/jsx/refresh.rs	Uses original expression/function spans for inserted refresh calls/statements.
crates/oxc_transformer/src/jsx/jsx_impl.rs	Uses JSX element span for generated props object/children array nodes.
crates/oxc_transformer/src/es2026/explicit_resource_management.rs	Threads statement spans into generated try/catch/finally scaffolding.
crates/oxc_transformer/src/es2022/class_properties/super_converter.rs	Updates helper calls to match new span-threaded builder signatures.
crates/oxc_transformer/src/es2022/class_properties/prop_decl.rs	Propagates `PropertyDefinition` spans into generated helper calls/assignments.
crates/oxc_transformer/src/es2022/class_properties/private_field.rs	Updates helper calls to match new span-threaded builder signatures.
crates/oxc_transformer/src/es2022/class_properties/constructor.rs	Updates helper calls to match new span-threaded builder signatures.
crates/oxc_transformer/src/es2022/class_properties/class.rs	Updates helper calls to match new span-threaded builder signatures.
crates/oxc_transformer/src/es2021/logical_assignment_operators.rs	Uses original assignment span for the rewritten logical expression node.
crates/oxc_transformer/src/es2020/optional_chaining.rs	Uses original chain-expression span for the rewritten conditional expression node.
crates/oxc_transformer/src/es2018/object_rest_spread.rs	Ensures the final rewritten call expression retains the original object expression span.
crates/oxc_transformer/src/es2018/async_generator_functions/for_await.rs	Propagates `for await` statement span through generated `for`/`try` scaffolding.
crates/oxc_transformer/src/es2017/async_to_generator.rs	Uses original await/arrow/function spans for rewritten yield/IIFE call nodes.
crates/oxc_transformer/src/es2016/exponentiation_operator.rs	Propagates original expression span through rewritten `Math.pow`/sequence nodes.
crates/oxc_transformer/src/decorator/legacy/mod.rs	Updates helper calls to match new span-threaded builder signatures.
crates/oxc_transformer/src/common/computed_key.rs	Updates computed-key temp-var assignment generation to use new span-threaded builder signature.
crates/oxc_transformer/src/common/arrow_function_converter.rs	Uses original spans for newly generated call expressions in super transforms.

Copilot · 2026-02-11T11:37:07Z

crates/oxc_transformer/src/common/computed_key.rs

    ctx.state.var_declarations.insert_let(&binding, None, ctx.ast);

-    let assignment = create_assignment(&binding, key, ctx);
+    let assignment = create_assignment(&binding, key, SPAN, ctx);
    let ident = binding.create_read_expression(ctx);


create_computed_key_temp_var passes SPAN into create_assignment, so the generated _tmp = <key> assignment will have an empty span and be skipped by sourcemap generation. Since this assignment corresponds to evaluating the original computed key expression, capture the original key span before moving it and pass that span instead.

### 🚀 Features - 429d876 semantic: Assign ast node ids during semantic build (#19263) (Boshen) - ebb80b3 ast: Add `node_id` field to all AST struct nodes (#18138) (Boshen) ### 🐛 Bug Fixes - bfb15a3 semantic: Make multi_index_vec clone panic-safe (#19299) (Boshen) - 41c50a5 transformer: Ignore invalid JSX pragma identifiers (#19296) (Boshen) - deed3d8 transformer: Remove unnecessary trailing expression in object rest spread assignment (#19259) (Boshen) - 5bdaacc transformer: Propagate source spans for sourcemap correctness (#19258) (Boshen) - 3e0e5ba isolated-declarations: Align readonly class array initializer diagnostics with tsc (#19218) (camc314) ### ⚡ Performance - c169c77 syntax: Optimize `is_identifier_name_patched` (#19386) (sapphi-red) - aa1e1a8 allocator: Inline BitSet accessors (#19331) (Boshen) - 5b90d46 semantic: Improve SoA with multi index vec (#19138) (Boshen) - 99ce2a6 isolated_declarations: Mark all diagnostic functions as `#[cold]` (#19279) (camc314) - dd0220f transformer: Remove TS-only nodes earlier in `enter_statements` (#19166) (Dunqing) - e5baf60 isolated-declarations: Replace hash collections with index-based Vec (#19221) (Dunqing) ### 📚 Documentation - 569aa61 rust: Add missing rustdocs and remove missing_docs lint attrs (#19306) (Boshen)

…xc-project#19258) ## Summary - Propagate original source node spans to their outermost transformed replacements across all transformer plugins - Codegen skips sourcemap entries for nodes with empty spans (`SPAN`), so transformed nodes previously produced no sourcemap mappings - Updated 20 files across typescript, jsx, es2016-es2026, class properties, and shared utility functions - Added `span: Span` parameters to shared helpers (`create_assignment`, `create_member_callee`, `create_prototype_member`) and threaded spans through call chains - Kept `SPAN` for truly synthetic nodes (generated temps, helper function internals, protocol boilerplate) 🤖 Generated with [Claude Code](https://claude.com/claude-code)

### 🚀 Features - 429d876 semantic: Assign ast node ids during semantic build (oxc-project#19263) (Boshen) - ebb80b3 ast: Add `node_id` field to all AST struct nodes (oxc-project#18138) (Boshen) ### 🐛 Bug Fixes - bfb15a3 semantic: Make multi_index_vec clone panic-safe (oxc-project#19299) (Boshen) - 41c50a5 transformer: Ignore invalid JSX pragma identifiers (oxc-project#19296) (Boshen) - deed3d8 transformer: Remove unnecessary trailing expression in object rest spread assignment (oxc-project#19259) (Boshen) - 5bdaacc transformer: Propagate source spans for sourcemap correctness (oxc-project#19258) (Boshen) - 3e0e5ba isolated-declarations: Align readonly class array initializer diagnostics with tsc (oxc-project#19218) (camc314) ### ⚡ Performance - c169c77 syntax: Optimize `is_identifier_name_patched` (oxc-project#19386) (sapphi-red) - aa1e1a8 allocator: Inline BitSet accessors (oxc-project#19331) (Boshen) - 5b90d46 semantic: Improve SoA with multi index vec (oxc-project#19138) (Boshen) - 99ce2a6 isolated_declarations: Mark all diagnostic functions as `#[cold]` (oxc-project#19279) (camc314) - dd0220f transformer: Remove TS-only nodes earlier in `enter_statements` (oxc-project#19166) (Dunqing) - e5baf60 isolated-declarations: Replace hash collections with index-based Vec (oxc-project#19221) (Dunqing) ### 📚 Documentation - 569aa61 rust: Add missing rustdocs and remove missing_docs lint attrs (oxc-project#19306) (Boshen)

github-actions bot added A-transformer Area - Transformer / Transpiler C-bug Category - Bug labels Feb 11, 2026

Boshen marked this pull request as ready for review February 11, 2026 11:33

Boshen requested review from Dunqing and overlookmotel as code owners February 11, 2026 11:33

Copilot AI review requested due to automatic review settings February 11, 2026 11:33

Boshen added the 0-merge Merge with Graphite Merge Queue label Feb 11, 2026

Copilot started reviewing on behalf of Boshen February 11, 2026 11:33 View session

graphite-app bot force-pushed the fix/transformer-sourcemap-spans branch from 941bc03 to 5bdaacc Compare February 11, 2026 11:34

Copilot AI reviewed Feb 11, 2026

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graphite-app bot merged commit 5bdaacc into main Feb 11, 2026
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graphite-app bot deleted the fix/transformer-sourcemap-spans branch February 11, 2026 11:40

graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Feb 11, 2026

Boshen mentioned this pull request Feb 16, 2026

release(crates): oxc v0.114.0 #19429

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fix(transformer): propagate source spans for sourcemap correctness#19258

fix(transformer): propagate source spans for sourcemap correctness#19258
graphite-app[bot] merged 1 commit intomainfrom
fix/transformer-sourcemap-spans

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Boshen commented Feb 11, 2026

Summary

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codspeed-hq bot commented Feb 11, 2026

Merging this PR will not alter performance

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