Reproduction link or steps
Create this minimal package:
{
"type": "module",
"scripts": {
"build": "rolldown -c",
"start": "node dist/out.mjs"
},
"dependencies": {
"mnemonist": "0.40.4",
"rolldown": "1.1.0"
}
}entry.mjs:
import { LRUCacheWithDelete } from 'mnemonist';
const cache = new LRUCacheWithDelete(2);
cache.set('a', 1);
console.log(cache.get('a'));rolldown.config.mjs:
export default {
input: 'entry.mjs',
output: {
file: 'dist/out.mjs',
format: 'esm'
}
};Run:
npm install
npm run build
npm run start
What is expected?
The bundled output should execute successfully and print:
What is actually happening?
The generated bundle throws at module evaluation time:
file:///private/tmp/rolldown-mnemonist-repro/dist/out.mjs:845
FibonacciHeap.MinFibonacciHeap;
^
ReferenceError: FibonacciHeap is not defined
at file:///private/tmp/rolldown-mnemonist-repro/dist/out.mjs:845:1The emitted bundle contains property reads for unused barrel re-export-derived bindings, but no bindings for the imported names:
module.exports = LRUCacheWithDelete;
})))(), 1);
FibonacciHeap.MinFibonacciHeap;
FibonacciHeap.MaxFibonacciHeap;
Heap.MinHeap;
Heap.MaxHeap;
SuffixArray.GeneralizedSuffixArray;
Vector.Uint8Vector;
Vector.Uint8ClampedVector;
Vector.Int8Vector;
Vector.Uint16Vector;
Vector.Int16Vector;
Vector.Uint32Vector;
Vector.Int32Vector;
Vector.Float32Vector;
Vector.Float64Vector;
Vector.PointerVector;
//#endregion
//#region entry.mjs
const cache = new import_lru_cache_with_delete.default(2);
cache.set("a", 1);
console.log(cache.get("a"));
//#endregionA quick scan of the generated file shows no declaration/import for FibonacciHeap:
FibonacciHeap.MinFibonacciHeap 26168
FibonacciHeap = -1
var FibonacciHeap -1
const FibonacciHeap -1
import_fibonacci -1
System Info
System:
OS: macOS 26.5
CPU: (14) arm64 Apple M4 Pro
Memory: 636.27 MB / 48.00 GB
Shell: 4.7.1 - /opt/homebrew/bin/fish
Binaries:
Node: 26.0.0 - /opt/homebrew/bin/node
Yarn: 1.22.22 - /opt/homebrew/bin/yarn
npm: 11.12.1 - /opt/homebrew/bin/npm
pnpm: 10.33.0 - /opt/homebrew/bin/pnpm
bun: 1.3.11 - /Users/abhi/.local/share/mise/installs/bun/latest/bin/bun
npmPackages:
rolldown: 1.1.0 => 1.1.0
Any additional comments?
mnemonist/index.mjs is a side-effect-free ESM barrel. It imports defaults from several modules and derives named re-export values, for example:
import {default as FibonacciHeap} from './fibonacci-heap.js';
const MinFibonacciHeap = FibonacciHeap.MinFibonacciHeap;
const MaxFibonacciHeap = FibonacciHeap.MaxFibonacciHeap;
export {FibonacciHeap, MinFibonacciHeap, MaxFibonacciHeap};
export {default as LRUCacheWithDelete} from './lru-cache-with-delete.js';The entry only imports LRUCacheWithDelete, but Rolldown keeps bare property reads for the other derived re-export values while dropping the imports that define the objects being read.
Adding this config makes the same repro execute successfully and print 1:
export default {
input: 'entry.mjs',
output: {
file: 'dist/out.mjs',
format: 'esm'
},
experimental: {
lazyBarrel: false
}
};
Reproduction link or steps
Create this minimal package:
{ "type": "module", "scripts": { "build": "rolldown -c", "start": "node dist/out.mjs" }, "dependencies": { "mnemonist": "0.40.4", "rolldown": "1.1.0" } }entry.mjs:rolldown.config.mjs:Run:
What is expected?
The bundled output should execute successfully and print:
What is actually happening?
The generated bundle throws at module evaluation time:
file:///private/tmp/rolldown-mnemonist-repro/dist/out.mjs:845 FibonacciHeap.MinFibonacciHeap; ^ ReferenceError: FibonacciHeap is not defined at file:///private/tmp/rolldown-mnemonist-repro/dist/out.mjs:845:1The emitted bundle contains property reads for unused barrel re-export-derived bindings, but no bindings for the imported names:
A quick scan of the generated file shows no declaration/import for
FibonacciHeap:System Info
System: OS: macOS 26.5 CPU: (14) arm64 Apple M4 Pro Memory: 636.27 MB / 48.00 GB Shell: 4.7.1 - /opt/homebrew/bin/fish Binaries: Node: 26.0.0 - /opt/homebrew/bin/node Yarn: 1.22.22 - /opt/homebrew/bin/yarn npm: 11.12.1 - /opt/homebrew/bin/npm pnpm: 10.33.0 - /opt/homebrew/bin/pnpm bun: 1.3.11 - /Users/abhi/.local/share/mise/installs/bun/latest/bin/bun npmPackages: rolldown: 1.1.0 => 1.1.0Any additional comments?
mnemonist/index.mjsis a side-effect-free ESM barrel. It imports defaults from several modules and derives named re-export values, for example:The entry only imports
LRUCacheWithDelete, but Rolldown keeps bare property reads for the other derived re-export values while dropping the imports that define the objects being read.Adding this config makes the same repro execute successfully and print
1: