Does it support modern Python versions?

Yes, it includes modern Python behaviors up to 3.13, including dictionary insertion ordering and updated warnings for module name shadowing.

What are Python 'gotchas'?

Gotchas are common pitfalls or unexpected behaviors in Python, such as mutable default arguments or late binding in closures, that frequently cause logic bugs even for experienced developers.

How does this skill help with debugging?

It provides immediate explanations and corrected code snippets for known Python evaluation rules that might be causing your code to behave unexpectedly, such as why a list is retaining items between function calls.

Can this skill help with floating point errors?

Absolutely. It provides specific implementation patterns using math.isclose() and the Decimal module to handle precision issues where 0.1 + 0.2 does not equal 0.3.

Python Gotchas & Pitfalls

Name: Python Gotchas & Pitfalls
Author: JosiahSiegel

byJosiahSiegel

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Developer Tools

Identifies and fixes subtle Python logic errors like mutable defaults, scope resolution issues, and iteration pitfalls to ensure production-grade code.

This skill acts as a comprehensive diagnostic and preventative tool for Python developers, focusing on the common 'gotchas' that often lead to difficult-to-trace bugs. It covers critical areas including mutable default arguments, list and dictionary mutation during iteration, the distinction between identity and equality, and complex variable scoping rules (LEGB). By providing clear problem explanations alongside standardized code fixes, it helps developers write more predictable, bug-free Python code while serving as an educational resource for best practices.

Key Features

017 GitHub stars

02Scope resolution guidance for LEGB rules and closure late-binding

03Standardized patterns for exception handling and circular import resolution

04Fixes for index-shifting errors when mutating collections during iteration

05Floating-point precision handling using math.isclose and Decimal

06Automatic detection and correction of mutable default arguments

Use Cases

01Debugging unexpected logic behavior in Python scripts and applications

02Conducting deep code reviews to prevent subtle runtime errors

03Learning and implementing Python's specific evaluation and scoping rules

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add josiahsiegel/claude-plugin-marketplace python-gotchas

For use in Claude.ai and ChatGPT

Download Skill