fix(semantic): no error in `check_function_redeclaration` for CommonJS files by overlookmotel · Pull Request #18231 · oxc-project/oxc

overlookmotel · 2026-01-19T12:47:11Z

I can't get my head around exactly what check_function_redeclaration is checking, so I'm not 100% sure about this change. But certainly this PR will make sure that behavior for CommonJS files is the same as it was before the introduction of commonjs source type.

Before commonjs source type existed:

Module: source_type.is_script() == false
Script: source_type.is_script() == true
CommonJS: source_type.is_script() == true

After introduction of commonjs source type:

Module: source_type.is_script() == false
Script: source_type.is_script() == true
CommonJS: source_type.is_script() == false (CHANGED)

After this PR:

Module: !source_type.is_module() == false
Script: !source_type.is_module() == true
CommonJS: !source_type.is_module() == true (CHANGED BACK)

overlookmotel · 2026-01-19T12:47:27Z

fix(semantic): no error in check_function_redeclaration for CommonJS files #18231 👈 (View in Graphite)
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codspeed-hq · 2026-01-19T12:52:56Z

Merging this PR will not alter performance

✅ 42 untouched benchmarks
⏩ 3 skipped benchmarks¹

_{Comparing om/01-19-fix_semantic_no_error_in_check_function_redeclaration_for_commonjs_files (f5fb3a7) with main (ee9f6a4)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 (f367769) during the generation of this report, so ee9f6a4 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

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Pull request overview

This PR fixes a regression in check_function_redeclaration that was introduced when the commonjs source type was added. The change restores the previous behavior where CommonJS files are treated like scripts (not modules) for function redeclaration checking.

Changes:

Updated the condition in check_function_redeclaration from is_script() to !is_module() to correctly identify non-module files (Script, CommonJS, and Unambiguous)

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Dunqing · 2026-01-19T13:11:02Z

Merge activity

Jan 19, 1:11 PM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Jan 19, 1:11 PM UTC: Dunqing added this pull request to the Graphite merge queue.
Jan 19, 1:27 PM UTC: Merged by the Graphite merge queue.

…S files (#18231) I can't get my head around exactly what `check_function_redeclaration` is checking, so I'm not 100% sure about this change. But certainly this PR will make sure that behavior for CommonJS files is the same as it was before the introduction of `commonjs` source type. Before `commonjs` source type existed: * Module: `source_type.is_script() == false` * Script: `source_type.is_script() == true` * CommonJS: `source_type.is_script() == true` After introduction of `commonjs` source type: * Module: `source_type.is_script() == false` * Script: `source_type.is_script() == true` * CommonJS: `source_type.is_script() == false` **(CHANGED)** After this PR: * Module: `!source_type.is_module() == false` * Script: `!source_type.is_module() == true` * CommonJS: `!source_type.is_module() == true` **(CHANGED BACK)**

### 🐛 Bug Fixes - f1e2dc0 semantic: No error in `check_function_redeclaration` for CommonJS files (#18231) (overlookmotel) - 645c3f0 transformer: Use `require` not `import` in CommonJS files (#18226) (overlookmotel) - ee9f6a4 mangler: Use `retain` instead of `truncate` to remove empty frequency slots (#18225) (Dunqing) ### ⚡ Performance - 52073d9 semantic: Use cheaper test for source type (#18235) (overlookmotel) Co-authored-by: overlookmotel <557937+overlookmotel@users.noreply.github.com>

Follow-on after #18231. Add test cases to make sure function redeclaration check works correctly in script, module, and CommonJS files.

github-actions bot added A-semantic Area - Semantic C-bug Category - Bug labels Jan 19, 2026

overlookmotel marked this pull request as ready for review January 19, 2026 12:54

overlookmotel requested a review from Dunqing as a code owner January 19, 2026 12:54

Copilot AI review requested due to automatic review settings January 19, 2026 12:54

Copilot started reviewing on behalf of overlookmotel January 19, 2026 12:54 View session

overlookmotel assigned overlookmotel and Dunqing Jan 19, 2026

Copilot AI reviewed Jan 19, 2026

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Dunqing approved these changes Jan 19, 2026

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Dunqing added the 0-merge Merge with Graphite Merge Queue label Jan 19, 2026

graphite-app bot force-pushed the om/01-19-fix_semantic_no_error_in_check_function_redeclaration_for_commonjs_files branch from f5fb3a7 to 4251813 Compare January 19, 2026 13:19

graphite-app bot force-pushed the om/01-19-fix_semantic_no_error_in_check_function_redeclaration_for_commonjs_files branch from 4251813 to f1e2dc0 Compare January 19, 2026 13:21

graphite-app bot merged commit f1e2dc0 into main Jan 19, 2026
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graphite-app bot deleted the om/01-19-fix_semantic_no_error_in_check_function_redeclaration_for_commonjs_files branch January 19, 2026 13:27

graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Jan 19, 2026

Boshen mentioned this pull request Jan 19, 2026

release(crates): oxc v0.110.0 #18240

Merged

overlookmotel mentioned this pull request Jan 20, 2026

test(semantic): add test cases for function redeclaration check #18288

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fix(semantic): no error in `check_function_redeclaration` for CommonJS files#18231

fix(semantic): no error in `check_function_redeclaration` for CommonJS files#18231
graphite-app[bot] merged 1 commit intomainfrom
om/01-19-fix_semantic_no_error_in_check_function_redeclaration_for_commonjs_files

overlookmotel commented Jan 19, 2026 •

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Merging this PR will not alter performance

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overlookmotel commented Jan 19, 2026 •

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