fight mypy[1]

The following error will be reported without if:

  error: Name "tomllib" already defined (by an import)

While this can be silenced by a "# type: ignore", in some case[2] mypy
will report the following error:

  error: Unused "type: ignore" comment

[1]: https://github.com/python/mypy/issues/1153
[2]: https://github.com/lilydjwg/nvchecker/actions/runs/4916840821/jobs/8793454970

nvchecker/core.py

@@ -12,6 +12,7 @@ import argparse
 from typing import (
   Tuple, NamedTuple, Optional, List, Union,
   cast, Dict, Awaitable, Sequence, Any,
+  TYPE_CHECKING,
 )
 import types
 from pathlib import Path
@@ -22,10 +23,13 @@ import json
 
 import structlog
 
-try:
-  import tomllib
-except ModuleNotFoundError:
-  import tomli as tomllib # type: ignore
+if TYPE_CHECKING:
+  import tomli as tomllib
+else:
+  try:
+    import tomllib
+  except ModuleNotFoundError:
+    import tomli as tomllib
 
 import platformdirs
 

nvchecker/util.py

@@ -14,10 +14,13 @@ from pathlib import Path
 import contextvars
 import abc
 
-try:
-  import tomllib
-except ModuleNotFoundError:
-  import tomli as tomllib # type: ignore
+if TYPE_CHECKING:
+  import tomli as tomllib
+else:
+  try:
+    import tomllib
+  except ModuleNotFoundError:
+    import tomli as tomllib
 
 import structlog
 

tests/conftest.py

@@ -5,11 +5,15 @@ import asyncio
 import structlog
 import os
 from pathlib import Path
+from typing import TYPE_CHECKING
 
-try:
-  import tomllib
-except ModuleNotFoundError:
-  import tomli as tomllib # type: ignore
+if TYPE_CHECKING:
+  import tomli as tomllib
+else:
+  try:
+    import tomllib
+  except ModuleNotFoundError:
+    import tomli as tomllib
 
 import pytest
 import pytest_asyncio