| |
| |
| """Lint: detect `with a() and b():` (boolean op in with-statement context). |
| |
| Using `and`/`or` to combine context managers is almost always a bug: |
| |
| with ctx_a() and ctx_b(): # BUG: only ctx_b is entered |
| with ctx_a() or ctx_b(): # BUG: only ctx_a is entered |
| |
| The correct way to combine context managers is: |
| |
| with ctx_a(), ctx_b(): # comma-separated |
| with (ctx_a(), ctx_b()): # parenthesized (Python 3.10+) |
| with contextlib.ExitStack() ... # ExitStack |
| """ |
|
|
| import ast |
| import sys |
|
|
|
|
| def check_file(filepath: str) -> list[str]: |
| try: |
| with open(filepath, encoding="utf-8") as f: |
| source = f.read() |
| except (OSError, UnicodeDecodeError): |
| return [] |
|
|
| try: |
| tree = ast.parse(source, filename=filepath) |
| except SyntaxError: |
| return [] |
|
|
| violations = [] |
| for node in ast.walk(tree): |
| if isinstance(node, (ast.With, ast.AsyncWith)): |
| for item in node.items: |
| if isinstance(item.context_expr, ast.BoolOp): |
| op = "and" if isinstance(item.context_expr.op, ast.And) else "or" |
| violations.append( |
| f"{filepath}:{item.context_expr.lineno}: " |
| f"boolean `{op}` used to combine context managers " |
| f"in `with` statement — use a comma instead" |
| ) |
| return violations |
|
|
|
|
| def main() -> int: |
| if len(sys.argv) < 2: |
| print("Usage: check_boolean_context_manager.py <file> ...", file=sys.stderr) |
| return 1 |
|
|
| all_violations = [] |
| for filepath in sys.argv[1:]: |
| all_violations.extend(check_file(filepath)) |
|
|
| if all_violations: |
| print( |
| "❌ Boolean operator used to combine context managers in `with` " |
| "statement.\n" |
| " `with a() and b():` only enters `b()` as a context manager.\n" |
| " Use `with a(), b():` or `with (a(), b()):` instead.\n" |
| ) |
| for v in all_violations: |
| print(f" {v}") |
| return 1 |
| return 0 |
|
|
|
|
| if __name__ == "__main__": |
| sys.exit(main()) |
|
|
