Run mypy on noxfile.py and be more restrictive

There is no reason to ignore imports, that only makes checking the types
weaker.

To be able to check types in a more strict way, we need to use packages
(-p) to avoid errors about having the same file in 2 packages
(src.frequenz.channels and frequenz.channels), so we need to translate
directory to package when running on `src`. Also we need to check
individual files separately.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

docs/mkdocstrings_autoapi.py

@@ -14,9 +14,9 @@
 SRC_PATH = "src"
 DST_PATH = "reference"
 
-# noqa because mkdocs_gen_files uses a very weird module-level
+# type ignore because mkdocs_gen_files uses a very weird module-level
 # __getattr__() which messes up the type system
-nav = mkdocs_gen_files.Nav()  # noqa
+nav = mkdocs_gen_files.Nav()  # type: ignore
 
 for path in sorted(Path(SRC_PATH).rglob("*.py")):
     module_path = path.relative_to(SRC_PATH).with_suffix("")

noxfile.py

@@ -34,18 +34,26 @@ def pylint(session: nox.Session) -> None:
 
 @nox.session
 def mypy(session: nox.Session) -> None:
-    session.install(".", "mypy")
-    session.run(
-        "mypy",
-        "--ignore-missing-imports",
+    """Run mypy to check type hints."""
+    session.install("-e", ".[docs]", "pytest", "nox", "mypy")
+
+    common_args = [
         "--namespace-packages",
         "--non-interactive",
         "--install-types",
         "--explicit-package-bases",
-        "--follow-imports=silent",
         "--strict",
-        *check_dirs,
-    )
+    ]
+
+    pkg_args = []
+    for pkg in check_dirs:
+        if pkg == "src":
+            pkg = "frequenz.channels"
+        pkg_args.append("-p")
+        pkg_args.append(pkg)
+
+    session.run("mypy", *common_args, *pkg_args)
+    session.run("mypy", *common_args, *check_files)
 
 
 @nox.session