Purpose¶

Consistent exception names make error handling code easier to scan and understand. This rule enforces a structured pattern: exceptions must start with an upper-case word, optionally followed by more words, and end with one of the recognised semantic suffixes (NotFound, Invalid, Denied, Conflict, or Failed) before the mandatory Error suffix.

Configuration¶

rules:
  - name: exception-naming
    type: class
    filter: { base_class: Exception }
    naming: { regex: "^[A-Z][a-zA-Z]+(NotFound|Invalid|Denied|Conflict|Failed)Error$" }

apply:
  - name: all
    rules: [exception-naming]
    modules: "**"

Violation Example¶

# src/domain/exceptions.py

class FilterError(Exception):   # missing semantic suffix before Error
    pass

Passing Example¶

# src/domain/exceptions.py

class FilterNotFoundError(Exception):
    pass

Output¶

$ pnl check
src/domain/exceptions.py:3
    [exception-naming] FilterError (expected pattern: ^[A-Z][a-zA-Z]+(NotFound|Invalid|...)Error$)

Found 1 violation(s).