Sample
Configure JsonSerializable options and enum decoding fallbacks in json_annotation, proving snake_case key enforcement, unknownEnumValue null bypass, and readValue error attribution
sha256:eabf9843a09e0a2fac2d9fe9f0df3eebd2f3eef2bf42bdd99120e6754d499267
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 JsonSerializable options and enum decoding fallbacks in json_annotation, proving snake_case key enforcement, unknownEnumValue null bypass, and readValue error attribution HOW
- Packages
-
json_annotation 4.9.0
- Environment
- dart
- Created
- 2026-08-17T14:38:30Z
Commonly assumed
A model expects JsonSerializable.fromJson to accept camelCase Dart option names, unknownEnumValue to serve as a fallback when an enum field is null, and disallowNullValues to reject missing keys.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- JsonSerializable.fromJson enforces snake_case option keys and disallowUnrecognizedKeys, throwing a CheckedFromJsonException with badKey true on camelCase Dart property names
- field_rename configuration parses exact enum string identifiers and throws an ArgumentError wrapped in CheckedFromJsonException on non-matching strings like screaming_snake
- $enumDecodeNullable returns the unknownValue fallback for unrecognized wire strings but returns null when the input is null, while non-nullable $enumDecode throws ArgumentError on null inputs even when unknownValue is provided
- JsonKey.nullForUndefinedEnumValue causes $enumDecodeNullable to map unrecognized wire strings to null, but passing an incompatible enum type throws an ArgumentError
- readValue custom extractors allow retrieving values from nested paths or aliases, and type mismatch exceptions are re-attributed to the target model field key in CheckedFromJsonException
- $checkKeys evaluates allowedKeys first, requiredKeys second, and disallowNullValues last, where disallowNullValues ignores completely absent keys unless combined with requiredKeys
- $checkedNew attaches the failing key name to CheckedFromJsonException for missing and disallowed-null keys, but leaves key as null for UnrecognizedKeysException
Files
- NOTES.md
- csx.json
- lib/account_config.dart
- 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