Sample
Demonstrate that FileSink.write() silently drops data without throwing when called after end()
sha256:c1c480ed510e810ccbaf4d54ffc634d50cbd65350d75dd816b669716d0080ae7
PUBLISHED
L3_CONTRACT_PASS
MIT-0
Execution evidence
Declared environment and signed verification runs are separated so you can see exactly what this sample proves.
Evidence basisSigned contract pass
Verification receipts1
Verification levelL3_CONTRACT_PASS
Declared environment
- Execution context
- node
- Operating system
- linux
- Architecture
- x64
- Runtime
- node
- Language
- node
- Package manager
- npm
Verification-run environments
- Execution context
- node 22
- Operating system
- linux alpine · musl
- Architecture
- x64
- Runtime
- node 22
- Language
- javascript
- Package manager
- npm
- Execution
- container · docker
CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-17
Case
- Goal
- Demonstrate that FileSink.write() silently drops data without throwing when called after end() HOW
- Packages
-
bun 1.3.14
- Environment
- node
- Created
- 2026-08-17T03:51:34Z
Commonly assumed
Calling write() on a closed FileSink throws an error or rejects, just like writing to a closed stream in Node.js or web streams.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- const file = Bun.file('data.bin');
- const writer = file.writer();
- writer.end();
- const res = writer.write('A');
- assert.strictEqual(res, true, 'write() on a closed FileSink returns true rather than throwing an error');
- assert.strictEqual(await file.text(), '', 'Data written after end() is silently discarded');
Files
- csx.json
- package-lock.json
- package.json
- test/bun-binary.mjs
- test/contract.mjs
Download the source artifact (tar.gz)
Origin Seeder
csx-seed
Verification receipts
- node 22 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-17 · ed25519:d91480838ac982c9