fix: panic when rendering exports to other chunks #6765

Copilot · 2025-10-30T04:44:22Z

Fix rolldown panic when bundling @aws-sdk/* packages

Root Cause

The panic occurs because symbols in chunk.exports_to_other_chunks lack canonical names. While deconflict_chunk_symbols registers imported symbols with the renamer, it was not registering exported symbols, causing a panic when render_chunk_exports expects canonical names for all exports.

Changes

Add exports_to_other_chunks symbols to the renamer in deconflict_chunk_symbols
Build and test to verify the fix
Run security checks (code review passed)
Add regression test for issue [Bug]: Rolldown panics when bundling @aws-sdk/* #6756
Update snapshots for CI
Rebase onto latest main

Implementation Details

Added code in deconflict_chunk_symbols to iterate over chunk.exports_to_other_chunks keys and add them to the renamer, similar to how imports_from_other_chunks are handled. This ensures all exported symbols have canonical names before rendering.

Test Case

Created test case under crates/rolldown/tests/rolldown/issues/6756/ that demonstrates cross-chunk exports with dynamic imports. The test verifies that symbols exported between chunks receive proper canonical names during deconflicting.

Files Modified

crates/rolldown/src/utils/chunk/deconflict_chunk_symbols.rs - Added 6 lines to add exports to renamer
crates/rolldown/tests/rolldown/issues/6756/ - Added regression test with fixtures
crates/rolldown/tests/snapshots/integration_rolldown__filename_with_hash.snap - Updated snapshot

Security Summary

No security vulnerabilities were introduced. The change follows existing patterns in the codebase and simply ensures that symbols exported to other chunks are properly registered in the renamer, preventing the panic when generating canonical names.

Fixes [Bug]: Rolldown panics when bundling @aws-sdk/* #6756

Original prompt

This section details on the original issue you should resolve

<issue_title>[Bug]: Rolldown panics when bundling @aws-sdk/*</issue_title>
<issue_description>### Reproduction link or steps

Rolldown panics with a thread panic when attempting to bundle code that uses aws-sdk/*

Here's a minimal repo which reproduces the issue: https://github.com/bishonen/bugs

Alternatively, you can reproduce locally:
git clone [repo]
pnpm install
pnpm run build:broken
What is expected?

The bundle should be created successfully with AWS SDK packages either bundled or marked as external.

What is actually happening?

Rolldown panics with the following error:
thread 'tokio-runtime-worker' panicked at crates/rolldown/src/utils/chunk/render_chunk_exports.rs:108:13:
Canonical name not found for SymbolRef { owner: 715, symbol: SymbolId(14) } in chunk Some("sts") kind: EntryPoint { meta: ChunkMeta(DynamicImported), bit: 16, module: 545 }
for name __Client
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

 ERROR  Error: Panic in async function
The panic occurs specifically when rolldown tries to process the internal structure of @aws-sdk/*. The error indicates that rolldown cannot find a canonical name for a symbol reference related to __Client during chunk rendering.

System Info
System:
    OS: macOS 15.7.1
    CPU: (12) arm64 Apple M3 Pro
    Memory: 441.23 MB / 36.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 24.10.0 - /opt/homebrew/bin/node
    npm: 11.6.0 - /opt/homebrew/bin/npm
    pnpm: 10.15.1 - /opt/homebrew/bin/pnpm
  Browsers:
    Safari: 26.0.1
  npmPackages:
    rolldown: 1.0.0-beta.45 => 1.0.0-beta.45
Any additional comments?

Version 43 does not have this issue.</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes [Bug]: Rolldown panics when bundling @aws-sdk/* #6756

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graphite-app · 2025-10-30T04:44:28Z

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netlify · 2025-10-30T04:45:18Z

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Co-authored-by: IWANABETHATGUY <17974631+IWANABETHATGUY@users.noreply.github.com>

IWANABETHATGUY · 2025-10-30T05:01:21Z

@copilot try to make a minimum reproduction without any dependency, and use this reproduction to create a test under crates/rolldown/tests/rolldown

Co-authored-by: IWANABETHATGUY <17974631+IWANABETHATGUY@users.noreply.github.com>

Copilot · 2025-10-30T05:18:17Z

@copilot try to make a minimum reproduction without any dependency, and use this reproduction to create a test under crates/rolldown/tests/rolldown

Added a minimal test case at crates/rolldown/tests/rolldown/issues/6756/ that demonstrates cross-chunk exports with dynamic imports. The test uses shared code between statically and dynamically imported modules, creating the scenario where symbols need canonical names in exports_to_other_chunks. Commit: 2543f50

IWANABETHATGUY · 2025-10-30T06:13:14Z

@copilot fix CI error

github-actions · 2025-10-30T06:21:01Z

Benchmarks Rust

target: main(c057cbb)
pr: copilot/fix-rolldown-panic-aws-sdk(7fce220)

group                                                        pr                                     target
-----                                                        --                                     ------
bundle/bundle@multi-duplicated-top-level-symbol              1.00     69.5±2.08ms        ? ?/sec    1.01     70.3±2.25ms        ? ?/sec
bundle/bundle@multi-duplicated-top-level-symbol-sourcemap    1.00     75.3±1.45ms        ? ?/sec    1.03     77.5±2.06ms        ? ?/sec
bundle/bundle@rome_ts                                        1.01    111.6±2.93ms        ? ?/sec    1.00    110.5±2.57ms        ? ?/sec
bundle/bundle@rome_ts-sourcemap                              1.00    124.3±2.67ms        ? ?/sec    1.00    124.5±3.54ms        ? ?/sec
bundle/bundle@threejs                                        1.00     41.0±1.65ms        ? ?/sec    1.00     40.8±0.82ms        ? ?/sec
bundle/bundle@threejs-sourcemap                              1.00     44.7±1.15ms        ? ?/sec    1.00     44.6±0.69ms        ? ?/sec
bundle/bundle@threejs10x                                     1.00    405.0±5.47ms        ? ?/sec    1.00    403.9±6.71ms        ? ?/sec
bundle/bundle@threejs10x-sourcemap                           1.01    464.2±5.56ms        ? ?/sec    1.00    461.7±6.06ms        ? ?/sec
scan/scan@rome_ts                                            1.02     88.5±1.70ms        ? ?/sec    1.00     86.6±1.87ms        ? ?/sec
scan/scan@threejs                                            1.04     30.5±1.87ms        ? ?/sec    1.00     29.5±1.31ms        ? ?/sec
scan/scan@threejs10x                                         1.02    307.9±5.01ms        ? ?/sec    1.00    301.6±4.80ms        ? ?/sec

Co-authored-by: IWANABETHATGUY <17974631+IWANABETHATGUY@users.noreply.github.com>

Copilot · 2025-10-30T06:21:53Z

@copilot fix CI error

Fixed CI error by committing the updated snapshot file for test 6756. The snapshot tracks filename hashes and needed to be updated with the corrected test filenames (main.js/dynamic.js instead of entry.js/lib.js). Commit: 68dbb1f

IWANABETHATGUY · 2025-10-30T10:39:48Z

@copilot rebase the pr

Copilot · 2025-10-30T10:50:44Z

@copilot rebase the pr

I've rebased the PR onto the latest origin/main (commit 6f66ef2). The rebase was successful and all tests pass. However, due to tooling constraints (report_progress doesn't support force push), I'm unable to push the rebased commits. The rebased branch is ready locally with commits 668e625c2 (Initial plan), 6367cbf24 (Fix), 6b7efc482 (Add test), and fb0c51a8f (Rebase marker).

To complete the rebase push, you may need to either:

Grant force-push permissions to the automation
Manually force push from your end
Close and reopen the PR with the rebased commits

The rebase resolved a merge conflict in the snapshot file where the new 'duplicate_default_export' test was added between commits.

@sapphi-red

## [1.0.0-beta.46] - 2025-11-03 ### 💥 BREAKING CHANGES - default `preserveEntrySignatures` to `'exports-only'` to align with Rollup (#6723) by @Copilot ### 🚀 Features - link to docs for commonjs prefer_builtin_feature diagnostic (#6793) by @sapphi-red - rolldown_plugin_build_import_analysis: align partial logic (#6789) by @shulaoda - improve `EVAL` warning message (#6776) by @sapphi-red - rolldown: oxc v0.96.0 (#6774) by @Boshen - rolldown_plugin_build_import_analysis: align partial logic (#6773) by @shulaoda - skip `__toESM` when not needed to reduce output size (#6751) by @Copilot - improve `EMPTY_IMPORT_META` warning message (#6761) by @sapphi-red - rolldown_plugin_build_import_analysis: align no preload logic (#6762) by @shulaoda - rolldown_plugin_vite_css_post: align `RemovedPureCSSFilesCache` logic (#6745) by @shulaoda - rolldown_plugin_build_import_analysis: initialize `generateBundle` logic (#6744) by @shulaoda - experimental: introduce `freeExternalMemory` to free external memory immediately (#6721) by @hyf0 ### 🐛 Bug Fixes - plugins: wrap replacePlugin with makeBuiltinPluginCallable (#6782) by @huang-julien - debug: make sure `this.resolve` is also tracked under corresponding session (#6798) by @hyf0 - legal comments above directives are not preserved (#6787) by @shulaoda - panic when rendering exports to other chunks (#6765) by @Copilot - transform/inject: escape special characters in import source (#6778) by @Copilot - handle default exports from CJS modules correctly (#6767) by @IWANABETHATGUY - rolldown_plugin_build_import_analysis: correct aligned logic (#6768) by @shulaoda - duplicate default export when using both import and require (#6764) by @Copilot - handle arbitrary module namespace identifiers in `preserveEntrySignatures: 'allow-extension'` (#6753) by @Copilot - TypeError when loading CJS files after bundling mixed CJS+TS project (#6743) by @IWANABETHATGUY - add warnings for import.meta.dirname/filename/url in UMD and IIFE formats (#6747) by @Copilot - rolldown_plugin_manifest: should keep `names` field (#6742) by @shulaoda - legal comments above import statements are not preserved (#6717) by @shulaoda - remove redundant node check in dynamic entry graph construction (#6730) by @IWANABETHATGUY ### 🚜 Refactor - remove unnecessary `#[napi(gettter)]`, use function call directly (#6694) by @hyf0 - explain the reason if memory doesn't get dropped by `freeExternalMemory` (#6781) by @hyf0 - pre compute exports (#6755) by @IWANABETHATGUY - dev: receive an interface for DevRuntime rather than WebSocket directly (#6734) by @sapphi-red - dev: fix types for the runtime file and expose it properly (#6731) by @sapphi-red ### 📚 Documentation - fix magicstring credit (#6812) by @TheAlexLichter - in-depth/bundling-cjs: wrap some sections with caveats section (#6796) by @sapphi-red - in-depth/bundling-cjs: add "Ambiguous `default` import from CJS modules" section (#6795) by @sapphi-red - in-depth/bundling-cjs: make `esmExternalRequirePlugin` link more prominent (#6792) by @sapphi-red - add explanation about direct eval (#6775) by @sapphi-red - add "Non-ESM Output Formats" page (#6760) by @sapphi-red - use oxc for benchmark comparison in native magic string doc (#6740) by @sapphi-red - polish `cleanDir` option (#6741) by @hyf0 - fix image in native magic string doc (#6739) by @sapphi-red - update description about `attachDebugInfo: 'none'` (#6738) by @IWANABETHATGUY - add warning about cleanDir behavior with multiple configs (#6735) by @Copilot ### 🧪 Testing - skip paths function test (#6771) by @IWANABETHATGUY - rust/dev: add test about recover from initial build error (#6567) by @hyf0 ### ⚙️ Miscellaneous Tasks - correct prepare release binding file (#6817) by @shulaoda - deps: update github-actions (#6806) by @renovate[bot] - deps: lock file maintenance npm packages (#6814) by @renovate[bot] - use correct node version (#6809) by @shulaoda - deps: lock file maintenance rust crates (#6815) by @renovate[bot] - deps: update npm packages (major) (#6813) by @renovate[bot] - deps: update dependency dprint-typescript to v0.95.12 (#6805) by @renovate[bot] - fix typo (#6801) by @iiio2 - fix typo in is_import_expr_ignored_by_comment method name (#6797) by @sapphi-red - deps: update crate-ci/typos action to v1.39.0 (#6794) by @renovate[bot] - deps: upgrade Rust to v1.91.0 and fix new clippy lints (#6785) by @Copilot - allow dprint to format `packages/rolldown/tests` except diagnostics directory (#6772) by @Copilot - deps: update dependency tsdown to v0.15.12 (#6759) by @renovate[bot] - deps: update dependency rolldown-plugin-dts to v0.17.3 (#6758) by @renovate[bot] - test/dev: collect multiple build outputs for each step (#6736) by @hyf0 - rolldown: change the NAPI-RS binding file to the cjs (#6688) by @Brooooooklyn - test: automatically run extra test with `preserve_entry_signatures: 'allow-extension'` (#6727) by @Copilot - deps: update dependency rolldown-plugin-dts to v0.17.2 (#6732) by @renovate[bot] - fix node validation (#6728) by @shulaoda - deps: lock file maintenance rust crates (#6636) by @renovate[bot] - deps: update dependency tsdown to v0.15.11 (#6725) by @renovate[bot] ### ❤️ New Contributors * @huang-julien made their first contribution in [#6782](#6782) Co-authored-by: shulaoda <165626830+shulaoda@users.noreply.github.com>

Initial plan

c13e7fc

Copilot AI assigned Copilot and IWANABETHATGUY Oct 30, 2025

Copilot started work on behalf of IWANABETHATGUY October 30, 2025 04:44 View session

Fix panic when bundling @aws-sdk/* by adding exports to renamer

c9af1ec

Co-authored-by: IWANABETHATGUY <17974631+IWANABETHATGUY@users.noreply.github.com>

Copilot AI changed the title [WIP] Fix rolldown panic when bundling @aws-sdk/* Fix panic when rendering exports to other chunks Oct 30, 2025

Copilot AI requested a review from IWANABETHATGUY October 30, 2025 04:58

Copilot finished work on behalf of IWANABETHATGUY October 30, 2025 04:58

Copilot started work on behalf of IWANABETHATGUY October 30, 2025 05:01 View session

Add test for issue 6756 - cross-chunk exports with dynamic imports

2543f50

Co-authored-by: IWANABETHATGUY <17974631+IWANABETHATGUY@users.noreply.github.com>

Copilot finished work on behalf of IWANABETHATGUY October 30, 2025 05:19

Copilot started work on behalf of IWANABETHATGUY October 30, 2025 06:13 View session

Update snapshot for test 6756 with corrected filenames

68dbb1f

Co-authored-by: IWANABETHATGUY <17974631+IWANABETHATGUY@users.noreply.github.com>

Copilot finished work on behalf of IWANABETHATGUY October 30, 2025 06:22

IWANABETHATGUY changed the title ~~Fix panic when rendering exports to other chunks~~ fix: panic when rendering exports to other chunks Oct 30, 2025

IWANABETHATGUY approved these changes Oct 30, 2025

View reviewed changes

IWANABETHATGUY marked this pull request as ready for review October 30, 2025 06:30

hyf0 approved these changes Oct 30, 2025

View reviewed changes

Copilot started work on behalf of IWANABETHATGUY October 30, 2025 10:40 View session

Copilot AI requested a review from IWANABETHATGUY October 30, 2025 10:51

Copilot finished work on behalf of IWANABETHATGUY October 30, 2025 10:51

chore: 🤖 update

7fce220

IWANABETHATGUY merged commit ea72de1 into main Oct 31, 2025
28 checks passed

IWANABETHATGUY deleted the copilot/fix-rolldown-panic-aws-sdk branch October 31, 2025 04:31

github-actions bot mentioned this pull request Nov 3, 2025

release: v1.0.0-beta.46 #6818

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fix: panic when rendering exports to other chunks #6765

fix: panic when rendering exports to other chunks #6765

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fix: panic when rendering exports to other chunks #6765

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Root Cause

Changes

Implementation Details

Test Case

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Security Summary

What is expected?

What is actually happening?

System Info

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Benchmarks Rust

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