flake8-frozen-collections 0.0.1

Flake8 plugin that requires frozendict and frozenset instead of dict and set

flake8-frozen-collections

A Flake8 plugin that prohibits the use of mutable dict and set, requiring frozendict and frozenset instead.

Installation

pip install flake8-frozen-collections

Usage

flake8 your_project/

Error Codes

Code	Description
FCS100	Use frozendict instead of dict
FCS200	Use frozenset instead of set

What Is Checked

• Literals {...} and {key: value}
• Calls to dict(...) and set(...)
• dict/set comprehensions
• Type annotations dict[...], set[...], dict, set
• Checks isinstance(..., dict) and isinstance(..., set)

Example

# Bad
mapping: dict[str, int] = {"a": 1}
tags: set[str] = {"x", "y"}

# Good
from frozendict import frozendict

mapping = frozendict({"a": 1})
tags = frozenset({"x", "y"})