fix: avoid rspack runtime name conflicts

[LingyuCoder]

Summary

• deconflict Rspack export runtime names per chunk and avoid reserving core runtime names for runtime-free ESM chunks
• use the actual rspackRequire module factory argument when handling nested bindings
• leave top-level ESM bindings to the ESM linker while preserving CJS factory parameter safety
• add execution coverage for context, exports, local CJS rspackRequire, and runtime-free exported function names

Testing

• corepack pnpm --filter @rspack/binding run build:dev
• corepack pnpm --parallel --filter '@rspack/*' test\n- targeted RuntimeModeEsmOutput regression cases\n- cargo check -p rspack_plugin_esm_library -p rspack_plugin_javascript

[chatgpt-codex-connector]

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Reviewed commit: 0b498c0b18

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[chatgpt-codex-connector]

Choose the nested name from the render mode

With experiments.runtimeMode: "rspack" and ordinary non-modern-module output, module code uses RspackContext, so the factory argument is __rspack_context while parser_runtime_requirements.require is the member expression __rspack_context.r. No declaration can match that string, leaving nested bindings named __rspack_context unchanged so they can shadow generated calls such as __rspack_context.r(...) and break a nested require(). This also regresses configCases/runtime/runtime-mode-nested-rspack-context, which explicitly expects the binding to be renamed; keep using the context name for RspackContext and use the require name only for RspackExport.

Useful? React with 👍 / 👎.

[chatgpt-codex-connector]

Limit the ESM binding exemption to export rendering

When Rspack runtime mode parses an ESM source for ordinary non-modern-module output, this predicate is still true even though no ESM linker will deconflict the binding; with concatenation disabled, the module is emitted inside a factory whose parameters include __rspack_exports and __rspack_context. A top-level declaration such as const __rspack_exports = ... is therefore skipped here and emitted as a lexical redeclaration of the factory parameter, making the bundle fail to parse. Restrict this exemption to the RspackExport render mode where the ESM linker actually handles top-level bindings.

Useful? React with 👍 / 👎.

[github-actions]

📦 Binary Size-limit

Comparing 0b498c0 to chore: migrate Rslib and Rsbuild to Rstack CLI (#14992) by Jiahan Chen

🙈 Size remains the same at 66.74MB

[github-actions]

Rsdoctor Bundle Diff Analysis

Found 5 projects in monorepo, 0 projects with changes.

📊 Quick Summary

Project	Total Size	Gzip Size	Change	Gzip Change
popular-libs	1.7 MB	552.1 KB	0	0
react-10k	5.6 MB	1.3 MB	0	0
react-1k	823.1 KB	217.0 KB	0	0
react-5k	2.7 MB	663.8 KB	0	0
ui-components	4.9 MB	1.4 MB	0	0

Generated by Rsdoctor GitHub Action

[codspeed]

Merging this PR will not alter performance

✅ 46 untouched benchmarks
⏩ 47 skipped benchmarks¹

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_{Comparing seal/fix-rspack-export-name-conflicts (0b498c0) with main (d9d0078)}

Footnotes

1. 47 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. ↩

[LingyuCoder]

Split into focused pull requests for easier review:

• fix: preserve context exports in rspack runtime mode #15001 — preserve context exports
• fix: avoid runtime scope conflicts in module factories #15002 — avoid CJS rspackRequire factory parameter conflicts
• fix: preserve direct exports bindings #15003 — preserve direct exports bindings
• fix: preserve runtime-free ESM binding names #15004 — avoid unused runtime name reservations