vllm/tools/check_init_lazy_imports.py

109 lines
3.5 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""Ensure we perform lazy loading in vllm/__init__.py.
i.e: appears only within the ``if typing.TYPE_CHECKING:`` guard,
**except** for a short whitelist.
"""
from __future__ import annotations
import ast
import pathlib
import sys
from collections.abc import Iterable
from typing import Final
REPO_ROOT: Final = pathlib.Path(__file__).resolve().parent.parent
INIT_PATH: Final = REPO_ROOT / "vllm" / "__init__.py"
# If you need to add items to whitelist, do it here.
ALLOWED_IMPORTS: Final[frozenset[str]] = frozenset({
"vllm.env_override",
})
ALLOWED_FROM_MODULES: Final[frozenset[str]] = frozenset({
".version",
})
def _is_internal(name: str | None, *, level: int = 0) -> bool:
if level > 0:
return True
if name is None:
return False
return name.startswith("vllm.") or name == "vllm"
def _fail(violations: Iterable[tuple[int, str]]) -> None:
print("ERROR: Disallowed eager imports in vllm/__init__.py:\n",
file=sys.stderr)
for lineno, msg in violations:
print(f" Line {lineno}: {msg}", file=sys.stderr)
sys.exit(1)
def main() -> None:
source = INIT_PATH.read_text(encoding="utf-8")
tree = ast.parse(source, filename=str(INIT_PATH))
violations: list[tuple[int, str]] = []
class Visitor(ast.NodeVisitor):
def __init__(self) -> None:
super().__init__()
self._in_type_checking = False
def visit_If(self, node: ast.If) -> None:
guard_is_type_checking = False
test = node.test
if isinstance(test, ast.Attribute) and isinstance(
test.value, ast.Name):
guard_is_type_checking = (test.value.id == "typing"
and test.attr == "TYPE_CHECKING")
elif isinstance(test, ast.Name):
guard_is_type_checking = test.id == "TYPE_CHECKING"
if guard_is_type_checking:
prev = self._in_type_checking
self._in_type_checking = True
for child in node.body:
self.visit(child)
self._in_type_checking = prev
for child in node.orelse:
self.visit(child)
else:
self.generic_visit(node)
def visit_Import(self, node: ast.Import) -> None:
if self._in_type_checking:
return
for alias in node.names:
module_name = alias.name
if _is_internal(
module_name) and module_name not in ALLOWED_IMPORTS:
violations.append((
node.lineno,
f"import '{module_name}' must be inside typing.TYPE_CHECKING", # noqa: E501
))
def visit_ImportFrom(self, node: ast.ImportFrom) -> None:
if self._in_type_checking:
return
module_as_written = ("." * node.level) + (node.module or "")
if _is_internal(
node.module, level=node.level
) and module_as_written not in ALLOWED_FROM_MODULES:
violations.append((
node.lineno,
f"from '{module_as_written}' import ... must be inside typing.TYPE_CHECKING", # noqa: E501
))
Visitor().visit(tree)
if violations:
_fail(violations)
if __name__ == "__main__":
main()