Make `mypy` behave like a proper pre-commit hook (#25313)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

.github/CODEOWNERS

@@ -72,6 +72,7 @@ mkdocs.yaml @hmellor
 # Linting
 .markdownlint.yaml @hmellor
 .pre-commit-config.yaml @hmellor
+/tools/pre_commit @hmellor
 
 # CPU
 /vllm/v1/worker/cpu* @bigPYJ1151

.pre-commit-config.yaml

@@ -60,38 +60,32 @@ repos:
     files: ^requirements/test\.(in|txt)$
   - id: mypy-local
     name: Run mypy for local Python installation
-    entry: tools/mypy.sh 0 "local"
-    language: python
-    types: [python]
-    additional_dependencies: &mypy_deps [mypy==1.11.1, types-cachetools, types-setuptools, types-PyYAML, types-requests, pydantic]
+    entry: python tools/pre_commit/mypy.py 0 "local"
     stages: [pre-commit] # Don't run in CI
+    <<: &mypy_common
+      language: python
+      types_or: [python, pyi]
+      require_serial: true
+      additional_dependencies: [mypy==1.11.1, regex, types-cachetools, types-setuptools, types-PyYAML, types-requests, types-torch, pydantic]
   - id: mypy-3.9 # TODO: Use https://github.com/pre-commit/mirrors-mypy when mypy setup is less awkward
     name: Run mypy for Python 3.9
-    entry: tools/mypy.sh 1 "3.9"
-    language: python
-    types: [python]
-    additional_dependencies: *mypy_deps
+    entry: python tools/pre_commit/mypy.py 1 "3.9"
+    <<: *mypy_common
     stages: [manual] # Only run in CI
   - id: mypy-3.10 # TODO: Use https://github.com/pre-commit/mirrors-mypy when mypy setup is less awkward
     name: Run mypy for Python 3.10
-    entry: tools/mypy.sh 1 "3.10"
-    language: python
-    types: [python]
-    additional_dependencies: *mypy_deps
+    entry: python tools/pre_commit/mypy.py 1 "3.10"
+    <<: *mypy_common
     stages: [manual] # Only run in CI
   - id: mypy-3.11 # TODO: Use https://github.com/pre-commit/mirrors-mypy when mypy setup is less awkward
     name: Run mypy for Python 3.11
-    entry: tools/mypy.sh 1 "3.11"
-    language: python
-    types: [python]
-    additional_dependencies: *mypy_deps
+    entry: python tools/pre_commit/mypy.py 1 "3.11"
+    <<: *mypy_common
     stages: [manual] # Only run in CI
   - id: mypy-3.12 # TODO: Use https://github.com/pre-commit/mirrors-mypy when mypy setup is less awkward
     name: Run mypy for Python 3.12
-    entry: tools/mypy.sh 1 "3.12"
-    language: python
-    types: [python]
-    additional_dependencies: *mypy_deps
+    entry: python tools/pre_commit/mypy.py 1 "3.12"
+    <<: *mypy_common
     stages: [manual] # Only run in CI
   - id: shellcheck
     name: Lint shell scripts

pyproject.toml

@@ -110,27 +110,6 @@ ignore_missing_imports = true
 check_untyped_defs = true
 follow_imports = "silent"
 
-# After fixing type errors resulting from follow_imports: "skip" -> "silent",
-# move the directory here and remove it from tools/mypy.sh
-files = [
-    "vllm/*.py",
-    "vllm/assets",
-    "vllm/entrypoints",
-    "vllm/inputs",
-    "vllm/logging_utils",
-    "vllm/multimodal",
-    "vllm/platforms",
-    "vllm/transformers_utils",
-    "vllm/triton_utils",
-    "vllm/usage",
-]
-# TODO(woosuk): Include the code from Megatron and HuggingFace.
-exclude = [
-    "vllm/model_executor/parallel_utils/|vllm/model_executor/models/",
-    # Ignore triton kernels in ops.
-    'vllm/attention/ops/.*\.py$'
-]
-
 [tool.isort]
 skip_glob = [
     ".buildkite/*",

tools/mypy.sh

-#!/bin/bash
-
-CI=${1:-0}
-PYTHON_VERSION=${2:-local}
-
-if [ "$CI" -eq 1 ]; then
-    set -e
-fi
-
-if [ $PYTHON_VERSION == "local" ]; then
-    PYTHON_VERSION=$(python -c 'import sys; print(f"{sys.version_info.major}.{sys.version_info.minor}")')
-fi
-
-run_mypy() {
-    echo "Running mypy on $1"
-    if [ "$CI" -eq 1 ] && [ -z "$1" ]; then
-        mypy --python-version "${PYTHON_VERSION}" "$@"
-        return
-    fi
-    mypy --follow-imports skip --python-version "${PYTHON_VERSION}" "$@"
-}
-
-run_mypy # Note that this is less strict than CI
-run_mypy tests
-run_mypy vllm/attention
-run_mypy vllm/compilation
-run_mypy vllm/distributed
-run_mypy vllm/engine
-run_mypy vllm/executor
-run_mypy vllm/inputs
-run_mypy vllm/lora
-run_mypy --exclude 'vllm/model_executor/layers/fla/ops' vllm/model_executor
-run_mypy vllm/plugins
-run_mypy vllm/worker
-run_mypy vllm/v1

tools/pre_commit/mypy.py

+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""
+Run mypy on changed files.
+
+This script is designed to be used as a pre-commit hook. It runs mypy
+on files that have been changed. It groups files into different mypy calls
+based on their directory to avoid import following issues.
+
+Usage:
+    python tools/pre_commit/mypy.py <ci> <python_version> <changed_files...>
+
+Args:
+    ci: "1" if running in CI, "0" otherwise. In CI, follow_imports is set to
+        "silent" for the main group of files.
+    python_version: Python version to use (e.g., "3.10") or "local" to use
+        the local Python version.
+    changed_files: List of changed files to check.
+"""
+
+import subprocess
+import sys
+from typing import Optional
+
+import regex as re
+
+FILES = [
+    "vllm/*.py",
+    "vllm/assets",
+    "vllm/entrypoints",
+    "vllm/inputs",
+    "vllm/logging_utils",
+    "vllm/multimodal",
+    "vllm/platforms",
+    "vllm/transformers_utils",
+    "vllm/triton_utils",
+    "vllm/usage",
+]
+
+# After fixing errors resulting from changing follow_imports
+# from "skip" to "silent", move the following directories to FILES
+SEPARATE_GROUPS = [
+    "tests",
+    "vllm/attention",
+    "vllm/compilation",
+    "vllm/distributed",
+    "vllm/engine",
+    "vllm/executor",
+    "vllm/inputs",
+    "vllm/lora",
+    "vllm/model_executor",
+    "vllm/plugins",
+    "vllm/worker",
+    "vllm/v1",
+]
+
+# TODO(woosuk): Include the code from Megatron and HuggingFace.
+EXCLUDE = [
+    "vllm/model_executor/parallel_utils",
+    "vllm/model_executor/models",
+    "vllm/model_executor/layers/fla/ops",
+    # Ignore triton kernels in ops.
+    "vllm/attention/ops",
+]
+
+
+def group_files(changed_files: list[str]) -> dict[str, list[str]]:
+    """
+    Group changed files into different mypy calls.
+
+    Args:
+        changed_files: List of changed files.
+
+    Returns:
+        A dictionary mapping file group names to lists of changed files.
+    """
+    exclude_pattern = re.compile(f"^{'|'.join(EXCLUDE)}.*")
+    files_pattern = re.compile(f"^({'|'.join(FILES)}).*")
+    file_groups = {"": []}
+    file_groups.update({k: [] for k in SEPARATE_GROUPS})
+    for changed_file in changed_files:
+        # Skip files which should be ignored completely
+        if exclude_pattern.match(changed_file):
+            continue
+        # Group files by mypy call
+        if files_pattern.match(changed_file):
+            file_groups[""].append(changed_file)
+            continue
+        else:
+            for directory in SEPARATE_GROUPS:
+                if re.match(f"^{directory}.*", changed_file):
+                    file_groups[directory].append(changed_file)
+                    break
+    return file_groups
+
+
+def mypy(targets: list[str], python_version: Optional[str],
+         follow_imports: Optional[str], file_group: str) -> int:
+    """
+    Run mypy on the given targets.
+    
+    Args:
+        targets: List of files or directories to check.
+        python_version: Python version to use (e.g., "3.10") or None to use
+            the default mypy version.
+        follow_imports: Value for the --follow-imports option or None to use
+            the default mypy behavior.
+        file_group: The file group name for logging purposes.
+
+    Returns:
+        The return code from mypy.
+    """
+    args = ["mypy"]
+    if python_version is not None:
+        args += ["--python-version", python_version]
+    if follow_imports is not None:
+        args += ["--follow-imports", follow_imports]
+    print(f"$ {' '.join(args)} {file_group}")
+    return subprocess.run(args + targets, check=False).returncode
+
+
+def main():
+    ci = sys.argv[1] == "1"
+    python_version = sys.argv[2]
+    file_groups = group_files(sys.argv[3:])
+
+    if python_version == "local":
+        python_version = f"{sys.version_info.major}.{sys.version_info.minor}"
+
+    returncode = 0
+    for file_group, changed_files in file_groups.items():
+        follow_imports = None if ci and file_group == "" else "skip"
+        if changed_files:
+            returncode |= mypy(changed_files, python_version, follow_imports,
+                               file_group)
+    return returncode
+
+
+if __name__ == "__main__":
+    sys.exit(main())

vllm/entrypoints/llm.py

@@ -1468,7 +1468,7 @@ class LLM:
 
     def _validate_and_add_requests(
         self,
-        prompts: Union[PromptType, Sequence[PromptType]],
+        prompts: Union[PromptType, Sequence[PromptType], DataPrompt],
         params: Union[SamplingParams, Sequence[SamplingParams], PoolingParams,
                       Sequence[PoolingParams]],
         *,
@@ -1478,7 +1478,7 @@ class LLM:
     ) -> None:
         if isinstance(prompts, (str, dict)):
             # Convert a single prompt to a list.
-            prompts = [prompts]
+            prompts = [prompts]  # type: ignore[list-item]
 
         num_requests = len(prompts)
         if isinstance(params, Sequence) and len(params) != num_requests:

vllm/entrypoints/renderer.py

@@ -280,7 +280,7 @@ class CompletionRenderer(BaseRenderer):
         if truncate_prompt_tokens < 0:
             truncate_prompt_tokens = self.model_config.max_model_len
 
-        if max_length is not None and truncate_prompt_tokens > max_length:
+        if max_length is not None and truncate_prompt_tokens > max_length:  # type: ignore[operator]
             raise ValueError(
                 f"truncate_prompt_tokens ({truncate_prompt_tokens}) "
                 f"cannot be greater than max_length ({max_length}). "

vllm/utils/__init__.py

@@ -551,9 +551,10 @@ class AsyncMicrobatchTokenizer:
                 # If every request uses identical kwargs we can run a single
                 # batched tokenizer call for a big speed-up.
                 if can_batch and len(prompts) > 1:
-                    encode_fn = partial(self.tokenizer, prompts, **kwargs)
+                    batch_encode_fn = partial(self.tokenizer, prompts,
+                                              **kwargs)
                     results = await self._loop.run_in_executor(
-                        self._executor, encode_fn)
+                        self._executor, batch_encode_fn)
 
                     for i, fut in enumerate(result_futures):
                         if not fut.done():
@@ -889,7 +890,7 @@ def get_open_port() -> int:
 
 def get_open_ports_list(count: int = 5) -> list[int]:
     """Get a list of open ports."""
-    ports = set()
+    ports = set[int]()
     while len(ports) < count:
         ports.add(get_open_port())
     return list(ports)
@@ -1279,7 +1280,7 @@ def as_list(maybe_list: Iterable[T]) -> list[T]:
 
 def as_iter(obj: Union[T, Iterable[T]]) -> Iterable[T]:
     if isinstance(obj, str) or not isinstance(obj, Iterable):
-        obj = [obj]
+        return [obj]  # type: ignore[list-item]
     return obj
 
 

vllm/utils/tensor_schema.py

@@ -22,9 +22,8 @@ class TensorShape:
         self.dims = dims
         self.dynamic_dims = dynamic_dims if dynamic_dims else set()
 
-    def resolve(self, **bindings: dict[str,
-                                       int]) -> tuple[Union[int, str], ...]:
-        resolved = []
+    def resolve(self, **bindings: int) -> tuple[Union[int, str], ...]:
+        resolved = list[Union[int, str]]()
         for dim in self.dims:
             if isinstance(dim, str) and dim in bindings:
                 resolved.append(bindings[dim])
@@ -159,7 +158,7 @@ class TensorSchema:
 
     def validate(self) -> None:
         type_hints = get_type_hints(self.__class__, include_extras=True)
-        shape_env = {}
+        shape_env = dict[str, int]()
 
         for field_name, field_type in type_hints.items():
             # Check if field is missing