Sample
Configure fallback handling and validation bounds for unmapped characters and undefined byte sequences in CodePage
sha256:e790c49d1fb497727a63db0bd94d5804512cbd6739117627ea6133dbbbd06ad9
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
- dart
- Operating system
- linux
- Architecture
- x64
- Runtime
- dart
- Language
- dart
- Package manager
- pub
Verification-run environments
- Execution context
- dart 3
- Operating system
- linux debian · glibc
- Architecture
- x64
- Runtime
- dart 3
- Language
- dart
- Package manager
- pub
- Execution
- container · docker
CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · pub@1 · 2026-08-17
Case
- Goal
- Configure fallback handling and validation bounds for unmapped characters and undefined byte sequences in CodePage HOW
- Packages
-
convert 3.1.2
- Environment
- dart
- Created
- 2026-08-17T13:02:57Z
Commonly assumed
CodePage.encode and CodePage.decode silently replace unmapped characters or undefined bytes with fallback tokens rather than throwing FormatException.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- CodePage.encode throws FormatException on unmapped characters unless configured with an in-range invalidCharacter byte, and CodePage.decode throws FormatException on undefined byte entries unless allowInvalid is set to true.
- latin2.encode('Price: 10€') throws FormatException because the Euro symbol is unmapped in ISO-8859-2.
- latin2.encode('Price: 10€', invalidCharacter: 0x3F) succeeds and substitutes the question mark byte 0x3F for the unmapped Euro character.
- latin2.encode('Price: 10€', invalidCharacter: 256) throws RangeError because invalidCharacter must be an integer within 0..255.
- latin2.decode([0x50, 0x80, 0x51]) throws FormatException because 0x80 is an undefined code point in ISO-8859-2.
- latin2.decode([0x50, 0x80, 0x51], allowInvalid: true) succeeds and emits Unicode replacement character U+FFFD for 0x80.
- latin2.decode([256]) throws FormatException with 'Not a byte value' while allowInvalid: true emits U+FFFD.
- CodePage('custom', 'ABC') throws ArgumentError because CodePage table definitions require exactly 256 characters.
Files
- NOTES.md
- csx.json
- pubspec.lock
- pubspec.yaml
- test/contract.dart
Download the source artifact (tar.gz)
Origin Seeder
csx-seed
Verification receipts
- dart 3 · linux debian/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · pub@1 · 2026-08-17 · ed25519:d91480838ac982c9