Python Code Review

Quick Reference

Review Checklist

PEP8 Style

• [ ] 4-space indentation (no tabs)
• [ ] Line length ≤79 characters (≤72 for docstrings/comments)
• [ ] Two blank lines around top-level definitions, one within classes
• [ ] Imports grouped: stdlib → third-party → local (blank line between groups)
• [ ] No whitespace inside brackets or before colons/commas
• [ ] Naming: snake_case for functions/variables, CamelCase for classes, UPPER_CASE for constants
• [ ] Inline comments separated by at least two spaces

Type Safety

• [ ] Type hints on all function parameters and return types
• [ ] No Any unless necessary (with comment explaining why)
• [ ] Proper T | None syntax (Python 3.10+)

Async Patterns

• [ ] No blocking calls (time.sleep, requests) in async functions
• [ ] Proper await on all coroutines

Error Handling

• [ ] No bare except: clauses
• [ ] Specific exception types with context
• [ ] raise ... from to preserve stack traces

Common Mistakes

• [ ] No mutable default arguments
• [ ] Using logger not print() for output
• [ ] f-strings preferred over .format() or %

Valid Patterns (Do NOT Flag)

These patterns are intentional and correct - do not report as issues:

• Type annotation vs type assertion - Annotations declare types but are not runtime assertions; don't confuse with missing validation
• Using `Any` when interacting with untyped libraries - Required when external libraries lack type stubs
• Empty `__init__.py` files - Valid for package structure, no code required
• `noqa` comments - Valid when linter rule doesn't apply to specific case
• Using `cast()` after runtime type check - Correct pattern to inform type checker of narrowed type

Context-Sensitive Rules

Only flag these issues when the specific conditions apply:

Gates (reporting workflow)

Complete in order. Do not advance until each pass condition is met.

1. Scope — Pass: You list every .py path (or explicit glob) you inspected this run.
2. False-positive screen — Pass: For each issue you plan to report, you checked Valid Patterns and Context-Sensitive Rules above; you drop or narrow the finding if those sections say not to flag it.
3. Evidence — Pass: Each remaining finding includes `[FILE:LINE]` (or a bounded line range). Symbols or short verbatim snippets may supplement the location anchor but do not replace it.
4. Verification protocol — Pass: You load review-verification-protocol and complete its mandatory steps for each reported issue before the user-facing write-up.
5. Ship — Pass: The user-visible output matches whatever structure that protocol requires (no issues-only dump that skips its checks).

When to Load References

• Reviewing code formatting/style → pep8-style.md
• Reviewing function signatures → type-safety.md
• Reviewing async def functions → async-patterns.md
• Reviewing try/except blocks → error-handling.md
• General Python review → common-mistakes.md

Review Questions

1. Does the code follow PEP8 formatting (indentation, line length, whitespace)?
2. Are imports properly grouped (stdlib → third-party → local)?
3. Do names follow conventions (snake_case, CamelCase, UPPER_CASE)?
4. Are all function signatures fully typed?
5. Are async functions truly non-blocking?
6. Do exceptions include meaningful context?
7. Are there any mutable default arguments?

Before reporting: complete Gates (reporting workflow) above (especially gate 4).