fix: support forcing Python on parametrized session (#958)

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

nox/manifest.py

@@ -358,8 +358,11 @@ def make_session(
         calls = Call.generate_calls(func, parametrize)
         for call in calls:
             long_names = []
-            if not multi:
+            if not multi or (
+                self._config.force_pythons and call.python in self._config.extra_pythons
+            ):
                 long_names.append(f"{name}{call.session_signature}")
+
             if func.python:
                 long_names.append(f"{name}-{func.python}{call.session_signature}")
                 # Ensure that specifying session-python will run all parameterizations.

tests/resources/noxfile_parametrize.py

@@ -0,0 +1,11 @@
+import nox
+
+
+@nox.session
+@nox.parametrize(
+    ["version"],
+    [["8.1.0"], ["7.5.0"]],
+    ["8.1.0", "7.5.0"],
+)
+def check_package_files(session: nox.Session, version: str):
+    pass

tests/test_main.py

@@ -150,6 +150,31 @@ def test_main_no_venv_error() -> None:
         nox.main()
 
 
+def test_main_param_force_python(monkeypatch: pytest.MonkeyPatch) -> None:
+    """
+    Check that Python can be forced if something is parametrized over other things.
+    """
+
+    # Check that --no-venv overrides force_venv_backend
+    monkeypatch.setattr(
+        sys,
+        "argv",
+        [
+            "nox",
+            "--noxfile",
+            os.path.join(RESOURCES, "noxfile_parametrize.py"),
+            "--sessions",
+            "check_package_files(7.5.0)",
+            "--force-python",
+            ".".join(str(v) for v in sys.version_info[:2]),
+        ],
+    )
+
+    with mock.patch("sys.exit") as sys_exit:
+        nox.main()
+        sys_exit.assert_called_once_with(0)
+
+
 def test_main_short_form_args(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(
         sys,