Registry / serialization / class-resolver

class-resolver

library0.7.1pypypi✓ verified 85d ago

A lightweight library for looking up and instantiating classes by name or key, with support for registration, aliases, and presets. Current version 0.7.1, requires Python >=3.10, weekly releases.

serialization data

pip install class-resolver

github ↗package ↗docs ↗

INSTALL

IMPORT

SIG · CLASS-RESOLVER

class-resolver

serializationpythonv0.7.1

Install

1.6s avg

Import

124ms

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 v0.7.1 · 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 0.132s · 18.3MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.6s · import 0.116s · 19MB

16MB installed

● package 16MB

Code

Verified usage

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

ClassResolver

✓ from class_resolver import ClassResolver

Hint

✓ from class_resolver import Hint

Resolver

✓ from class_resolver import Resolver

Contributions

✓ from class_resolver import Contributions

Optional

✓ from class_resolver import Optional

Create a resolver from a base class or a list of classes, then look up and instantiate by registered name.

from class_resolver import ClassResolver class MyModel: name = 'my_model' class AnotherModel: name = 'another_model' resolver = ClassResolver.from_subclasses(MyModel) # Or manually: # resolver = ClassResolver([MyModel, AnotherModel]) # Look up by name or class model_class = resolver.lookup('my_model') # Instantiate with parameters instance = resolver.make('my_model', param1=10) print(instance)

Debug

Known issues

gotchaClass names are lowercased by default for lookup (e.g., 'MyModel' -> 'my_model'). To preserve original case, pass `suffix=''` or customize `suffix` parameter.

fix

Use `ClassResolver(classes, suffix='')` or override with custom normalization.

affects: all

gotcha`ClassResolver.from_subclasses()` only finds subclasses that are imported. If you define classes in separate modules, ensure they are imported before calling `from_subclasses`.

fix

Import all subclass modules explicitly before calling `from_subclasses()`.

affects: all

breakingIn version 0.7.0, `ClassResolver.make()` now passes extra kwargs to the constructor. Previously, extra kwargs were ignored. This may break code that relied on silent ignoring.

fix

Ensure that kwargs passed to `make()` are valid constructor arguments for the resolved class.

affects: >=0.7.0

deprecatedThe `Optional` alias for `Contributions` is deprecated since 0.7.0. Use `Contributions` directly.

fix

Replace `Optional` with `Contributions` in type hints.

affects: >=0.7.0

Errors

Common errors & fixes

AttributeError: module 'class_resolver' has no attribute 'ClassResolver'

Misspelled or incorrect import name. The module is `class_resolver` (with underscore), not `classresolver`.

fix

`from class_resolver import ClassResolver`

KeyError: 'xyz'

Attempted to lookup a class that is not registered in the resolver.

fix

Check registered names with `resolver.names` or ensure the class is properly added.

TypeError: __init__() got an unexpected keyword argument 'unexpected'

Passed an unexpected keyword argument to `resolver.make()`. In versions >=0.7.0, extra kwargs are passed to the constructor, which may cause an error if the class does not accept them.

fix

Remove unexpected kwargs or filter them before calling `make()`.

Upgrade

Version history

0.7.1latest on PyPI · released Aug 28, 2025

Audit

Dependencies

No dependency data recorded yet.

Agent activity

12 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/cthoyt/class-resolver ↗

packagehttps://pypi.org/project/class-resolver/ ↗

docshttps://class_resolver.readthedocs.io ↗