CodeSampleX

Sample

crypto 3.0.7: Prove that Dart's Digest class retains a mutable reference to its backing byte list, uses reference identity for its bytes property comparison, and that AccumulatorSink only emits a digest upon closing.

Verified sample for pub crypto 3.0.7: Prove that Dart's Digest class retains a mutable reference to its backing byte list, uses reference identity for its…

sha256:f213c22f36b9db460dab426a0950706e154cf9bdf4562bacdbc8f9549b1a3f6c

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
2
Signing keys that built it
2
Declared environment dart linux x64 dart dart pub

Verification-run environments

Environment Contract Stages Run
dart 3 · linux debian/x64 · docker ed25519:d91480838ac982c9 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · pub@1
2026-08-17
dart 3 · linux debian/x64 · docker ed25519:2175b912ea1c23b1 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · pub@1
2026-08-18

Case

HOW
Goal
Prove that Dart's Digest class retains a mutable reference to its backing byte list, uses reference identity for its bytes property comparison, and that AccumulatorSink only emits a digest upon closing.
Packages
Symbols
  • Digest
  • Digest.bytes
  • AccumulatorSink
  • Hash.startChunkedConversion
Environment
dart
Created
2026-08-17T02:04:59Z

Contract

  1. assert that a Digest constructed with a mutable List holds that list by reference, so modifying the list externally alters the Digest's bytes, its hex string representation, and its hash code
  2. assert that comparing raw byte lists of two identical Digest objects directly via the == operator evaluates to false due to Dart's list reference identity check, whereas comparing the Digest objects evaluates to true
  3. assert that AccumulatorSink remains empty when adding chunks via a chunked conversion sink and only receives a single Digest event when the sink is closed
  4. assert that calling add on a closed chunked conversion sink throws a StateError

Files

  • NOTES.md
  • csx.json
  • pubspec.lock
  • pubspec.yaml
  • test/contract.dart

Download the source artifact (tar.gz)

Origin Seeder

csx-seed