CodeSampleX

Sample

Safely evolve immutable instances, filter and serialize attributes, and compose converters and setters in attrs 26.1.0

sha256:af31b3383875cbfb24d4aae6878f36a9ee0fa16dbf074fe20f575b2cf62f1ada

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

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Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment python linux 24 · ubuntu · glibc 2.39 x64 python python pip

Verification-run environments

Environment Contract Stages Run
python 3.12 · linux alpine/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · python@1python:3.12-alpine@sha256:d09d15e60962…
2026-08-28

Case

HOW
Goal
Safely evolve immutable instances, filter and serialize attributes, and compose converters and setters in attrs 26.1.0
Packages
Symbols
  • attrs.asdict
  • attrs.converters.default_if_none
  • attrs.converters.pipe
  • attrs.evolve
  • attrs.filters.exclude
  • attrs.filters.include
  • attrs.setters.pipe
Environment
python
Created
2026-08-28T04:07:50Z

Contract

  1. assert attrs.evolve creates new instances with updated fields on frozen classes while keeping original instances intact
  2. assert attrs.evolve runs converters and validators on modified attribute values
  3. assert attrs.evolve raises TypeError on unknown attributes or init=False fields and NotAnAttrsClassError on non-attrs classes
  4. assert attrs.evolve preserves subclass identity and inherited attributes across class hierarchies
  5. assert attrs.converters.pipe chains multiple transformation functions sequentially
  6. assert attrs.converters.default_if_none provides scalar fallbacks or executes a factory on None
  7. assert attrs.setters.pipe chains convert and validate hooks on attribute mutation
  8. assert attrs.asdict supports attribute filtering via attrs.filters.include and attrs.filters.exclude by type and Attribute object
  9. assert attrs.asdict retains container collection types and allows selective value transformation via value_serializer
  10. assert attrs.asdict supports shallow serialization when recurse=False

Files

  • NOTES.md
  • PROMPT.md
  • csx.json
  • requirements.txt
  • spec.json
  • src/__init__.py
  • src/models.py
  • test/__init__.py
  • test/contract.py

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