fields

library5.0.0pypypi✓ verified 86d ago

A Python library for eliminating class boilerplate by providing an attrs/dataclass-like container class with built-in validation and transformation. Current version is 5.0.0, released on 2025-12-05. Development appears slow; pre-5.0.0 releases were irregular.

serialization

pip install fields

github ↗package ↗

INSTALL

IMPORT

SIG · FIELDS

fields

serializationpythonv5.0.0

Install

1.5s avg

Import

—

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v5.0.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.000s · 17.9MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.5s · import 0.000s · 18MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Fields

✓ from fields import Fields

✗ from fields import Field

BareFields

✓ from fields import BareFields

ConvertibleFields

✓ from fields import ConvertibleFields

Define a container class with automatic __init__, __repr__, and validation via type hints and Field descriptors.

from fields import fields, Field @fields class Point: x: int = Field(required=True) y: int = 0 p = Point(x=3) print(p.x, p.y) # 3 0

Debug

Known issues

breakingClassmethod and staticmethod descriptors conflict with field inspection; avoid using them inside @fields classes.

fix

Define classmethods/staticmethods outside the @fields class or use a different decorator pattern.

affects: >=1.0.0

gotchaField name checking uses both the slot name and the variable name; renaming a field variable but not updating the Field's 'name' argument can cause silent failures.

fix

Use keyword argument 'name' only when necessary; prefer relying on the variable name.

affects: >=1.0.0

deprecatedThe 'validate' parameter in Field is deprecated in 5.0.0; use the 'check' parameter instead.

fix

Replace Field(validate=func) with Field(check=func).

affects: 5.0.0

Upgrade

Version history

5.0.0latest on PyPI · released Apr 13, 2016

Audit

Dependencies

No dependency data recorded yet.

Agent activity

6 hits · last 30 days

node

Resources

githubhttps://github.com/ionelmc/python-fields ↗

packagehttps://pypi.org/project/fields/ ↗