Add type hints (#349)

Author: adamchainz

.pre-commit-config.yaml

@@ -42,3 +42,7 @@ repos:
   hooks:
   - id: check-manifest
     args: [--no-build-isolation]
+- repo: https://github.com/pre-commit/mirrors-mypy
+  rev: v0.910
+  hooks:
+  - id: mypy

HISTORY.rst

@@ -2,6 +2,8 @@
 History
 =======
 
+* Add type hints.
+
 3.5.0 (2021-05-10)
 ------------------
 

MANIFEST.in

@@ -5,6 +5,7 @@ prune requirements
 include HISTORY.rst
 include LICENSE
 include README.rst
+include src/flake8_comprehensions/py.typed
 exclude .editorconfig
 exclude .pre-commit-config.yaml
 include pyproject.toml

pyproject.toml

@@ -7,3 +7,18 @@ target-version = ['py36']
 
 [tool.isort]
 profile = "black"
+
+[tool.mypy]
+check_untyped_defs = true
+disallow_any_generics = true
+disallow_incomplete_defs = true
+disallow_untyped_defs = true
+mypy_path = "src/"
+no_implicit_optional = true
+show_error_codes = true
+warn_unreachable = true
+warn_unused_ignores = true
+
+[[tool.mypy.overrides]]
+module = "tests.*"
+allow_untyped_defs = true

setup.cfg

@@ -30,14 +30,17 @@ license_file = LICENSE
 [options]
 package_dir=
     =src
-py_modules = flake8_comprehensions
+packages = find:
 include_package_data = True
 install_requires =
     flake8>=3.0,!=3.2.0,<4
     importlib-metadata ; python_version < "3.8"
 python_requires = >=3.6
 zip_safe = False
 
+[options.packages.find]
+where = src
+
 [options.entry_points]
 flake8.extension =
     C4 = flake8_comprehensions:ComprehensionChecker

src/flake8_comprehensions.py renamed to src/flake8_comprehensions/__init__.py

@@ -1,5 +1,6 @@
 import ast
 import sys
+from typing import Any, Generator, Optional, Tuple, Type
 
 if sys.version_info >= (3, 8):
     from importlib.metadata import version
@@ -17,7 +18,7 @@ class ComprehensionChecker:
 
     __slots__ = ("tree",)
 
-    def __init__(self, tree, *args, **kwargs):
+    def __init__(self, tree: ast.Module) -> None:
         self.tree = tree
 
     messages = {
@@ -40,7 +41,7 @@ def __init__(self, tree, *args, **kwargs):
         "C416": "C416 Unnecessary {type} comprehension - rewrite using {type}().",
     }
 
-    def run(self):
+    def run(self) -> Generator[Tuple[int, int, str, Type[Any]], None, None]:
         for node in ast.walk(self.tree):
             if isinstance(node, ast.Call) and isinstance(node.func, ast.Name):
                 num_positional_args = len(node.args)
@@ -164,7 +165,7 @@ def run(self):
                 ):
                     remediation = ""
                     if node.func.id == "reversed":
-                        reverse_flag_value = False
+                        reverse_flag_value: Optional[bool] = False
                         for keyword in node.args[0].keywords:
                             if keyword.arg != "reverse":
                                 continue
@@ -260,11 +261,11 @@ def run(self):
                     )
 
 
-def has_star_args(call_node):
+def has_star_args(call_node: ast.Call) -> bool:
     return any(isinstance(a, ast.Starred) for a in call_node.args)
 
 
-def has_double_star_args(call_node):
+def has_double_star_args(call_node: ast.Call) -> bool:
     return any(k.arg is None for k in call_node.keywords)