Files
scylladb/.github/instructions/python.instructions.md
Piotr Szymaniak 378bcd69e3 tree: add AGENTS.md router and improve AI instruction files
Add AGENTS.md as a minimal router that directs AI agents to the
relevant instruction files based on what they are editing.

Improve the instruction files:

- cpp.instructions.md: clarify seastarx.hh scope (headers, not
  "many files"), explain std::atomic restriction (single-shard
  model, not "blocking"), scope macros prohibition to new ad-hoc
  only, add coroutine exception propagation pattern, add invariant
  checking section preferring throwing_assert() over SCYLLA_ASSERT
  (issue #7871)
- python.instructions.md: demote PEP 8 to fallback after local
  style, clarify that only wildcard imports are prohibited
- copilot-instructions.md: show configure.py defaults to dev mode,
  add frozen toolchain section, clarify --no-gather-metrics applies
  to test.py, fix Python test paths to use .py extension, add
  license header guidance for new files

Closes scylladb/scylladb#29023
2026-04-19 21:59:52 +03:00

52 lines
1.4 KiB
Markdown

---
applyTo: "**/*.py"
---
# Python Guidelines
**Important:** Match existing code style. Some directories (like `test/cqlpy` and `test/alternator`) prefer simplicity over type hints and docstrings.
## Style
- Match style of the file and directory you are editing; fall back to PEP 8 if unclear
- Use type hints for function signatures (unless directory style omits them)
- Use f-strings for formatting
- Line length: 160 characters max
- 4 spaces for indentation
## Imports
Order: standard library, third-party, local imports
```python
import os
import sys
import pytest
from cassandra.cluster import Cluster
from test.utils import setup_keyspace
```
Avoid wildcard imports (`from module import *`).
## Documentation
All public functions/classes need docstrings (unless the current directory conventions omit them):
```python
def my_function(arg1: str, arg2: int) -> bool:
"""
Brief summary of function purpose.
Args:
arg1: Description of first argument.
arg2: Description of second argument.
Returns:
Description of return value.
"""
pass
```
## Testing Best Practices
- Maintain bisectability: all tests must pass in every commit
- Mark currently-failing tests with `@pytest.mark.xfail`, unmark when fixed
- Use descriptive names that convey intent
- Docstrings/comments should explain what the test verifies and why, and if it reproduces a specific issue or how it fits into the larger test suite