Add mypy hook to pre-commit

.pre-commit-config.yaml

@@ -72,6 +72,15 @@ repos:
     - flake8-pytest-style>=1.0.0
     - wemake-python-styleguide
 
+- repo: https://github.com/pre-commit/mirrors-mypy
+  rev: v0.782
+  hooks:
+  - id: mypy
+    # empty args needed in order to match mypy cli behavior
+    args: []
+    additional_dependencies:
+    - Sphinx>=3.1.2
+
 - repo: local
   hooks:
   - id: pylint

mypy.ini

@@ -0,0 +1,18 @@
+[mypy]
+python_version = 3.6
+color_output = True
+error_summary = True
+
+check_untyped_defs = True
+
+disallow_untyped_calls = True
+disallow_any_generics = True
+
+follow_imports = normal
+
+ignore_missing_imports = False
+
+strict_optional = True
+
+warn_redundant_casts = True
+warn_unused_ignores = True

src/sphinxcontrib/towncrier/__init__.py

@@ -5,9 +5,10 @@
 import sys
 from functools import lru_cache
 from pathlib import Path
-from typing import Any, Dict, List, Union
+from typing import Dict, List, Tuple, Union
 
 from sphinx.application import Sphinx
+from sphinx.config import Config as SphinxConfig
 from sphinx.util.docutils import SphinxDirective
 from sphinx.util.nodes import nested_parse_with_titles, nodes
 
@@ -35,7 +36,7 @@ def _get_changelog_draft_entries(
         config_path: str = None,
 ) -> str:
     """Retrieve the unreleased changelog entries from Towncrier."""
-    extra_cli_args = (
+    extra_cli_args: Tuple[str, ...] = (
         '--version',
         rf'\ {target_version}',  # version value to be used in the RST title
         # NOTE: The escaped space sequence (`\ `) is necessary to address
@@ -66,7 +67,10 @@ def _get_changelog_draft_entries(
 
 
 @lru_cache(maxsize=1, typed=True)
-def _get_draft_version_fallback(strategy: str, sphinx_config: Dict[str, Any]):
+def _get_draft_version_fallback(
+        strategy: str,
+        sphinx_config: SphinxConfig,
+) -> str:
     """Generate a fallback version string for towncrier draft."""
     known_strategies = {'draft', 'sphinx-version', 'sphinx-release'}
     if strategy not in known_strategies:

src/sphinxcontrib/towncrier/_scm_version.pyi

@@ -0,0 +1,3 @@
+# This stub file is necessary because `_scm_version.py`
+# autogenerated on build and absent on mypy checks time
+version: str