Add session.invoked_from (#472)

* Add original cwd to session properties

* Fix test

* Rename original_wd to invoked_from

* Hoist invoked_from up to the options parser

* Add test case for hidden options

* Add test case for groupless options

Co-authored-by: Thea Flowers <me@thea.codes>

nox/_option_set.py

@@ -77,7 +77,7 @@ def __init__(
         self,
         name: str,
         *flags: str,
-        group: OptionGroup,
+        group: Optional[OptionGroup],
         help: Optional[str] = None,
         noxfile: bool = False,
         merge_func: Optional[Callable[[Namespace, Namespace], Any]] = None,
@@ -230,9 +230,15 @@ def parser(self) -> ArgumentParser:
         }
 
         for option in self.options.values():
-            if option.hidden:
+            if option.hidden is True:
                 continue
 
+            # Every option must have a group (except for hidden options)
+            if option.group is None:
+                raise ValueError(
+                    f"Option {option.name} must either have a group or be hidden."
+                )
+
             argument = groups[option.group.name].add_argument(
                 *option.flags, help=option.help, default=option.default, **option.kwargs
             )

nox/_options.py

@@ -474,6 +474,14 @@ def _session_completer(
         hidden=True,
         finalizer_func=_color_finalizer,
     ),
+    # Stores the original working directory that Nox was invoked from,
+    # since it could be different from the Noxfile's directory.
+    _option_set.Option(
+        "invoked_from",
+        group=None,
+        hidden=True,
+        default=lambda: os.getcwd(),
+    ),
 )
 
 

nox/sessions.py

@@ -189,6 +189,18 @@ def interactive(self) -> bool:
         """Returns True if Nox is being run in an interactive session or False otherwise."""
         return not self._runner.global_config.non_interactive and sys.stdin.isatty()
 
+    @property
+    def invoked_from(self) -> str:
+        """The directory that Nox was originally invoked from.
+
+        Since you can use the ``--noxfile / -f`` command-line
+        argument to run a Noxfile in a location different from your shell's
+        current working directory, Nox automatically changes the working directory
+        to the Noxfile's directory before running any sessions. This gives
+        you the original working directory that Nox was invoked form.
+        """
+        return self._runner.global_config.invoked_from
+
     def chdir(self, dir: Union[str, os.PathLike]) -> None:
         """Change the current working directory."""
         self.log(f"cd {dir}")

nox/tasks.py

@@ -60,7 +60,8 @@ def load_nox_module(global_config: Namespace) -> Union[types.ModuleType, int]:
         # Move to the path where the Noxfile is.
         # This will ensure that the Noxfile's path is on sys.path, and that
         # import-time path resolutions work the way the Noxfile author would
-        # guess.
+        # guess. The original working directory (the directory that Nox was
+        # invoked from) gets stored by the .invoke_from "option" in _options.
         os.chdir(noxfile_parent_dir)
         return importlib.machinery.SourceFileLoader(
             "user_nox_module", global_config.noxfile

tests/test__option_set.py

@@ -55,6 +55,29 @@ def test_namespace_non_existant_options_with_values(self):
         with pytest.raises(KeyError):
             optionset.namespace(non_existant_option="meep")
 
+    def test_parser_hidden_option(self):
+        optionset = _option_set.OptionSet()
+        optionset.add_options(
+            _option_set.Option(
+                "oh_boy_i_am_hidden", hidden=True, group=None, default="meep"
+            )
+        )
+
+        parser = optionset.parser()
+        namespace = parser.parse_args([])
+        optionset._finalize_args(namespace)
+
+        assert namespace.oh_boy_i_am_hidden == "meep"
+
+    def test_parser_groupless_option(self):
+        optionset = _option_set.OptionSet()
+        optionset.add_options(
+            _option_set.Option("oh_no_i_have_no_group", group=None, default="meep")
+        )
+
+        with pytest.raises(ValueError):
+            optionset.parser()
+
     def test_session_completer(self):
         parsed_args = _options.options.namespace(sessions=(), keywords=(), posargs=[])
         all_nox_sessions = _options._session_completer(

tests/test_sessions.py

@@ -67,7 +67,10 @@ def make_session_and_runner(self):
             signatures=["test"],
             func=func,
             global_config=_options.options.namespace(
-                posargs=[], error_on_external_run=False, install_only=False
+                posargs=[],
+                error_on_external_run=False,
+                install_only=False,
+                invoked_from=os.getcwd(),
             ),
             manifest=mock.create_autospec(nox.manifest.Manifest),
         )
@@ -104,6 +107,7 @@ def test_properties(self):
         assert session.bin_paths is runner.venv.bin_paths
         assert session.bin is runner.venv.bin_paths[0]
         assert session.python is runner.func.python
+        assert session.invoked_from is runner.global_config.invoked_from
 
     def test_no_bin_paths(self):
         session, runner = self.make_session_and_runner()
@@ -155,6 +159,17 @@ def test_chdir(self, tmpdir):
         assert os.getcwd() == cdto
         os.chdir(current_cwd)
 
+    def test_invoked_from(self, tmpdir):
+        cdto = str(tmpdir.join("cdbby").ensure(dir=True))
+        current_cwd = os.getcwd()
+
+        session, _ = self.make_session_and_runner()
+
+        session.chdir(cdto)
+
+        assert session.invoked_from == current_cwd
+        os.chdir(current_cwd)
+
     def test_chdir_pathlib(self, tmpdir):
         cdto = str(tmpdir.join("cdbby").ensure(dir=True))
         current_cwd = os.getcwd()