CodeSampleX

Sample

args 2.7.0: Prove how package:args caches and shares mutable default list instances across parses for unprovided multi-options

Verified sample for pub args 2.7.0: Prove how package:args caches and shares mutable default list instances across parses for unprovided multi-options. The…

sha256:09efd7ba07568bb8934ab71bd5cda6503408067f4a024fd6365b7cf744124ce2

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 how package:args caches and shares mutable default list instances across parses for unprovided multi-options
Packages
Symbols
  • ArgParser
  • ArgParser.addMultiOption
  • ArgResults
  • ArgResults.multiOption
  • ArgResults.arguments
  • ArgResults.rest
Environment
dart
Created
2026-08-17T06:45:46Z

Contract

  1. ArgResults.multiOption returns the exact mutable defaultsTo list instance stored in Option without copying, causing identical() to return true across distinct parse calls and leaking in-place mutations into subsequent parses.
  2. assert mutating the list returned from an unparsed multiOption modifies the parser default for subsequent parse calls
  3. assert implicit default multi-options share the same empty mutable list across parse invocations
  4. assert explicitly provided CLI multi-options allocate a distinct unshared list that does not affect the default
  5. assert ArgResults.arguments and ArgResults.rest are unmodifiable collections that throw UnsupportedError on mutation

Files

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

Download the source artifact (tar.gz)

Origin Seeder

csx-seed