style: Add mypy type checks, fixes

.github/workflows/linters.yaml

@@ -28,7 +28,20 @@ jobs:
       - name: Check out
         uses: actions/checkout@v3
 
+      - name: Install poetry
+        run: pipx install poetry
+
       - name: Set up python environment
         uses: actions/setup-python@v4
+        with:
+          cache: 'poetry'
+
+      - run: poetry install --no-root --with=dev --sync
+
+      - uses: actions/cache@v3
+        with:
+          path: ~/.cache/pre-commit
+          key: pre-commit-3|${{ env.pythonLocation }}|${{ hashFiles('.pre-commit-config.yaml') }}
 
-      - uses: pre-commit/[email protected]
+      - run: poetry run pre-commit run --show-diff-on-failure --color=always --all-files
+        shell: bash

.pre-commit-config.yaml

@@ -14,6 +14,15 @@ repos:
     hooks:
       - id: black
 
+  - repo: local
+    hooks:
+      - id: mypy
+        name: mypy
+        entry: poetry run mypy
+        require_serial: true
+        language: system
+        types: [python]
+
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: "v4.4.0"
     hooks:

podcast_archiver/argparse.py

@@ -7,7 +7,8 @@
 from pydantic import types
 
 if TYPE_CHECKING:
-    from pydantic import BaseSettings, ModelField
+    from pydantic import BaseSettings
+    from pydantic.fields import ModelField
 
 
 class readable_file(argparse.Action):

podcast_archiver/config.py

@@ -2,7 +2,7 @@
 
 import textwrap
 from pathlib import Path
-from typing import TYPE_CHECKING, Union
+from typing import TYPE_CHECKING, Any, Union
 
 from pydantic import BaseSettings, DirectoryPath, Field, FilePath, validator
 from yaml import safe_load
@@ -95,13 +95,13 @@ class Config:
     )
 
     @validator("archive_directory", pre=True)
-    def normalize_archive_directory(cls, v):
+    def normalize_archive_directory(cls, v) -> Path:
         if v is None:
             return Path.cwd()
         return Path(v).expanduser()
 
     @validator("opml_files", pre=True, each_item=True)
-    def normalize_opml_files(cls, v):
+    def normalize_opml_files(cls, v: Any) -> Path:
         return Path(v).expanduser()
 
     @classmethod
@@ -111,7 +111,7 @@ def load_from_yaml(cls, path: Union[Path, None]) -> Settings:
                 content = safe_load(filep)
             if content:
                 return cls.parse_obj(content)
-        return cls()
+        return cls()  # type: ignore[call-arg]
 
     @classmethod
     def load_and_merge(cls, path: Union[Path, None], args: argparse.Namespace):
@@ -132,7 +132,7 @@ def load_and_merge(cls, path: Union[Path, None], args: argparse.Namespace):
         return cls.parse_obj(merged_settings)
 
     @classmethod
-    def generate_example(cls, path: Path) -> str:
+    def generate_example(cls, path: Path) -> None:
         text = ["## Configuration for podcast-archiver"]
         text.append(f"## Generated with version {__version__}\n")
         for name, field in cls.__fields__.items():