Add mypy

.github/workflows/ci.yml

@@ -36,6 +36,32 @@ jobs:
       - name: Format
         run: poetry run ruff format . --check
 
+  typecheck:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.11"
+
+      - uses: actions/cache@v4
+        with:
+          path: ~/.cache/pip
+          key: pip-3.11-${{ hashFiles('poetry.lock') }}
+
+      - name: Install poetry
+        uses: abatilo/actions-poetry@v2
+        with:
+          poetry-version: 1.8.2
+
+      - name: Install Dependencies
+        run: poetry install
+
+      - name: Lint
+        run: poetry run mypy .
+
   test:
     runs-on: ubuntu-latest
     steps:
@@ -67,6 +93,7 @@ jobs:
     needs:
       - lint
       - test
+      - typecheck
     steps:
       - uses: actions/checkout@v4
 

calmerge/__init__.py

@@ -4,7 +4,7 @@
 from .config import Config
 
 
-def get_aiohttp_app(config: Config):
+def get_aiohttp_app(config: Config) -> web.Application:
     app = web.Application()
     app["config"] = config
 

calmerge/__main__.py

@@ -9,22 +9,22 @@
 from .config import Config
 
 
-def file_path(path: str):
-    path = Path(path).resolve()
+def file_path(path: str) -> Path:
+    path_obj = Path(path).resolve()
 
-    if not path.is_file():
+    if not path_obj.is_file():
         raise argparse.ArgumentTypeError(f"File not found: {path}")
 
-    return path
+    return path_obj
 
 
-def serve(args: argparse.Namespace):
+def serve(args: argparse.Namespace) -> None:
     config = Config.from_file(args.config)
     print(f"Found {len(config.calendars)} calendar(s)")
     run_app(get_aiohttp_app(config), port=int(os.environ.get("PORT", args.port)))
 
 
-def validate_config(args: argparse.Namespace):
+def validate_config(args: argparse.Namespace) -> None:
     try:
         Config.from_file(args.config)
     except ValidationError as e:
@@ -33,6 +33,8 @@ def validate_config(args: argparse.Namespace):
     else:
         print("Config is valid!")
 
+    return None
+
 
 def get_parser() -> argparse.ArgumentParser:
     parser = argparse.ArgumentParser(prog="calmerge")
@@ -51,7 +53,7 @@ def get_parser() -> argparse.ArgumentParser:
     return parser
 
 
-def main():
+def main() -> None:
     parser = get_parser()
     args = parser.parse_args()
 

calmerge/calendars.py

@@ -10,7 +10,7 @@
 fetch_cache = Cache(Cache.MEMORY, ttl=3600)
 
 
-async def fetch_calendar(session: ClientSession, url: str):
+async def fetch_calendar(session: ClientSession, url: str) -> icalendar.Calendar:
     cache_key = "calendar_" + url
     cached_calendar_data = await fetch_cache.get(cache_key)
 
@@ -22,7 +22,7 @@ async def fetch_calendar(session: ClientSession, url: str):
     return icalendar.Calendar.from_ical(cached_calendar_data)
 
 
-async def fetch_merged_calendar(calendar_config: CalendarConfig):
+async def fetch_merged_calendar(calendar_config: CalendarConfig) -> icalendar.Calendar:
     merged_calendar = icalendar.Calendar()
 
     async with ClientSession() as session:
@@ -36,7 +36,7 @@ async def fetch_merged_calendar(calendar_config: CalendarConfig):
     return merged_calendar
 
 
-def offset_calendar(calendar: icalendar.Calendar, offset_days: int):
+def offset_calendar(calendar: icalendar.Calendar, offset_days: int) -> None:
     """
     Mutate a calendar and move events by a given offset
     """

calmerge/config.py

@@ -22,7 +22,7 @@ def expand_vars(cls, v: str) -> str:
     def as_basic_auth(self) -> BasicAuth:
         return BasicAuth(self.username, self.password)
 
-    def validate_header(self, auth_header) -> bool:
+    def validate_header(self, auth_header: str) -> bool:
         try:
             parsed_auth_header = BasicAuth.decode(auth_header)
         except ValueError:
@@ -57,11 +57,11 @@ class Config(BaseModel):
     calendars: list[CalendarConfig] = Field(alias="calendar", default_factory=list)
 
     @classmethod
-    def from_file(cls, path: Path):
+    def from_file(cls, path: Path) -> "Config":
         with path.open(mode="rb") as f:
             return Config.model_validate(tomllib.load(f))
 
-    def get_calendar_by_name(self, name: str):
+    def get_calendar_by_name(self, name: str) -> CalendarConfig | None:
         return next(
             (calendar for calendar in self.calendars if calendar.name == name), None
         )

calmerge/utils.py

@@ -1,4 +1,4 @@
-def try_parse_int(val: str):
+def try_parse_int(val: str) -> int | None:
     try:
         return int(val)
     except (ValueError, TypeError):

calmerge/views.py

@@ -5,11 +5,11 @@
 from .utils import try_parse_int
 
 
-async def healthcheck(request):
+async def healthcheck(request: web.Request) -> web.Response:
     return web.Response(text="")
 
 
-async def calendar(request):
+async def calendar(request: web.Request) -> web.Response:
     config = request.app["config"]
 
     calendar_config = config.get_calendar_by_name(request.match_info["name"])
@@ -25,7 +25,7 @@ async def calendar(request):
     calendar = await fetch_merged_calendar(calendar_config)
 
     if calendar_config.allow_custom_offset and (
-        offset_days := try_parse_int(request.query.get("offset_days"))
+        offset_days := try_parse_int(request.query.get("offset_days", ""))
     ):
         if abs(offset_days) > MAX_OFFSET:
             raise web.HTTPBadRequest(

pyproject.toml

@@ -19,6 +19,7 @@ pytest = "^8.1.1"
 pytest-aiohttp = "^1.0.5"
 pytest-asyncio = "^0.23.5.post1"
 pytest-cov = "^4.1.0"
+mypy = "^1.9.0"
 
 [build-system]
 requires = ["poetry-core"]
@@ -36,3 +37,17 @@ ignore = ["E501"]
 
 [tool.pytest.ini_options]
 asyncio_mode = "auto"
+
+[tool.mypy]
+warn_unused_ignores = true
+warn_return_any = true
+show_error_codes = true
+strict_optional = true
+implicit_optional = true
+disallow_subclassing_any = true
+disallow_untyped_calls = true
+disallow_untyped_defs = true
+disallow_incomplete_defs = true
+disallow_untyped_decorators = true
+check_untyped_defs = true
+ignore_missing_imports = true

tests/conftest.py

@@ -1,6 +1,9 @@
+from asyncio import AbstractEventLoop
 from pathlib import Path
+from typing import Callable
 
 import pytest
+from aiohttp.test_utils import TestClient
 
 from calmerge import get_aiohttp_app
 from calmerge.config import Config
@@ -12,5 +15,7 @@ def config() -> Config:
 
 
 @pytest.fixture
-def client(event_loop, aiohttp_client, config):
-    return event_loop.run_until_complete(aiohttp_client(get_aiohttp_app(config)))
+def client(
+    event_loop: AbstractEventLoop, aiohttp_client: Callable, config: Config
+) -> TestClient:
+    return event_loop.run_until_complete(aiohttp_client(get_aiohttp_app(config)))  # type: ignore

tests/test_calendar_view.py

@@ -3,24 +3,25 @@
 import icalendar
 import pytest
 from aiohttp import BasicAuth
+from aiohttp.test_utils import TestClient
 
 from calmerge.config import MAX_OFFSET
 
 
-async def test_retrieves_calendars(client):
+async def test_retrieves_calendars(client: TestClient) -> None:
     response = await client.get("/python.ics")
     assert response.status == 200
 
     calendar = icalendar.Calendar.from_ical(await response.text())
     assert not calendar.is_broken
 
 
-async def test_404_without_auth(client):
+async def test_404_without_auth(client: TestClient) -> None:
     response = await client.get("/python-authed.ics")
     assert response.status == 404
 
 
-async def test_requires_auth(client):
+async def test_requires_auth(client: TestClient) -> None:
     response = await client.get(
         "/python-authed.ics", auth=BasicAuth("user", "password")
     )
@@ -30,15 +31,15 @@ async def test_requires_auth(client):
     assert not calendar.is_broken
 
 
-async def test_offset(client):
+async def test_offset(client: TestClient) -> None:
     response = await client.get("/python-offset.ics")
     assert response.status == 200
 
     calendar = icalendar.Calendar.from_ical(await response.text())
     assert not calendar.is_broken
 
 
-async def test_offset_calendar_matches(client):
+async def test_offset_calendar_matches(client: TestClient) -> None:
     offset_response = await client.get("/python-offset.ics")
     offset_calendar = icalendar.Calendar.from_ical(await offset_response.text())
 
@@ -75,7 +76,7 @@ async def test_offset_calendar_matches(client):
 
 
 @pytest.mark.parametrize("offset", [100, -100, MAX_OFFSET, -MAX_OFFSET])
-async def test_custom_offset(client, offset):
+async def test_custom_offset(client: TestClient, offset: int) -> None:
     offset_response = await client.get(
         "/python-custom-offset.ics",
         params={"offset_days": offset},
@@ -107,7 +108,7 @@ async def test_custom_offset(client, offset):
 
 
 @pytest.mark.parametrize("offset", [MAX_OFFSET + 1, -MAX_OFFSET - 1])
-async def test_out_of_bounds_custom_offset(client, offset):
+async def test_out_of_bounds_custom_offset(client: TestClient, offset: int) -> None:
     response = await client.get(
         "/python-custom-offset.ics",
         params={"offset_days": offset},