feat: Add session tags (#627)

docs/config.rst

@@ -429,6 +429,7 @@ The following options can be specified in the Noxfile:
 * ``nox.options.sessions`` is equivalent to specifying :ref:`-s or --sessions <opt-sessions-pythons-and-keywords>`. If set to an empty list, no sessions will be run if no sessions were given on the command line, and the list of available sessions will be shown instead.
 * ``nox.options.pythons`` is equivalent to specifying :ref:`-p or --pythons <opt-sessions-pythons-and-keywords>`.
 * ``nox.options.keywords`` is equivalent to specifying :ref:`-k or --keywords <opt-sessions-pythons-and-keywords>`.
+* ``nox.options.tags`` is equivalent to specifying :ref:`-t or --tags <opt-sessions-pythons-and-keywords>`.
 * ``nox.options.default_venv_backend`` is equivalent to specifying :ref:`-db or --default-venv-backend <opt-default-venv-backend>`.
 * ``nox.options.force_venv_backend`` is equivalent to specifying :ref:`-fb or --force-venv-backend <opt-force-venv-backend>`.
 * ``nox.options.reuse_existing_virtualenvs`` is equivalent to specifying :ref:`--reuse-existing-virtualenvs <opt-reuse-existing-virtualenvs>`. You can force this off by specifying ``--no-reuse-existing-virtualenvs`` during invocation.

docs/tutorial.rst

@@ -448,6 +448,58 @@ read more about parametrization and see more examples over at
 .. _pytest's parametrize: https://pytest.org/latest/parametrize.html#_pytest.python.Metafunc.parametrize
 
 
+Session tags
+------------
+
+You can add tags to your sessions to help you organize your development tasks:
+
+.. code-block:: python
+
+    @nox.session(tags=["style", "fix"])
+    def black(session):
+        session.install("black")
+        session.run("black", "my_package")
+
+    @nox.session(tags=["style", "fix"])
+    def isort(session):
+        session.install("isort")
+        session.run("isort", "my_package")
+
+    @nox.session(tags=["style"])
+    def flake8(session):
+        session.install("flake8")
+        session.run("flake8", "my_package")
+
+
+If you run ``nox -t style``, Nox will run all three sessions:
+
+.. code-block:: console
+
+    * black
+    * isort
+    * flake8
+
+
+If you run ``nox -t fix``, Nox will only run the ``black`` and ``isort``
+sessions:
+
+.. code-block:: console
+
+    * black
+    * isort
+    - flake8
+
+
+If you run ``nox -t style fix``, Nox will all sessions that match *any* of
+the tags, so all three sessions:
+
+.. code-block:: console
+
+    * black
+    * isort
+    * flake8
+
+
 Next steps
 ----------
 

docs/usage.rst

@@ -74,12 +74,15 @@ If you have a :ref:`configured session's virtualenv <virtualenv config>`, you ca
     nox --python 3.8
     nox -p 3.7 3.8
 
-You can also use `pytest-style keywords`_ to filter test sessions:
+You can also use `pytest-style keywords`_ using ``-k`` or ``--keywords``, and
+tags using ``-t`` or ``--tags`` to filter test sessions:
 
 .. code-block:: console
 
     nox -k "not lint"
     nox -k "tests and not lint"
+    nox -k "not my_tag"
+    nox -t "my_tag" "my_other_tag"
 
 .. _pytest-style keywords: https://docs.pytest.org/en/latest/usage.html#specifying-tests-selecting-tests
 

nox/_decorators.py

@@ -61,6 +61,7 @@ class Func(FunctionDecorator):
         venv_backend: Any = None,
         venv_params: Any = None,
         should_warn: dict[str, Any] | None = None,
+        tags: list[str] | None = None,
     ):
         self.func = func
         self.python = python
@@ -68,6 +69,7 @@ class Func(FunctionDecorator):
         self.venv_backend = venv_backend
         self.venv_params = venv_params
         self.should_warn = should_warn or dict()
+        self.tags = tags or []
 
     def __call__(self, *args: Any, **kwargs: Any) -> Any:
         return self.func(*args, **kwargs)
@@ -81,6 +83,7 @@ class Func(FunctionDecorator):
             self.venv_backend,
             self.venv_params,
             self.should_warn,
+            self.tags,
         )
 
 
@@ -109,6 +112,7 @@ class Call(Func):
             func.venv_backend,
             func.venv_params,
             func.should_warn,
+            func.tags,
         )
         self.call_spec = call_spec
         self.session_signature = session_signature

nox/_options.py

@@ -285,6 +285,15 @@ options.add_options(
         merge_func=functools.partial(_sessions_and_keywords_merge_func, "keywords"),
         help="Only run sessions that match the given expression.",
     ),
+    _option_set.Option(
+        "tags",
+        "-t",
+        "--tags",
+        group=options.groups["sessions"],
+        noxfile=True,
+        nargs="*",
+        help="Only run sessions with the given tags.",
+    ),
     _option_set.Option(
         "posargs",
         "posargs",

nox/manifest.py

@@ -172,9 +172,20 @@ class Manifest:
                 session names are checked against.
         """
         self._queue = [
-            x for x in self._queue if keyword_match(keywords, x.signatures + [x.name])
+            x
+            for x in self._queue
+            if keyword_match(keywords, x.signatures + x.tags + [x.name])
         ]
 
+    def filter_by_tags(self, tags: list[str]) -> None:
+        """Filter sessions by their tags.
+
+        Args:
+            tags (list[str]): A list of tags which session names
+                are checked against.
+        """
+        self._queue = [x for x in self._queue if set(x.tags).intersection(tags)]
+
     def make_session(
         self, name: str, func: Func, multi: bool = False
     ) -> list[SessionRunner]:

nox/registry.py

@@ -41,6 +41,7 @@ def session_decorator(
     name: str | None = ...,
     venv_backend: Any = ...,
     venv_params: Any = ...,
+    tags: list[str] | None = ...,
 ) -> Callable[[F], F]:
     ...
 
@@ -53,6 +54,7 @@ def session_decorator(
     name: str | None = None,
     venv_backend: Any = None,
     venv_params: Any = None,
+    tags: list[str] | None = None,
 ) -> F | Callable[[F], F]:
     """Designate the decorated function as a session."""
     # If `func` is provided, then this is the decorator call with the function
@@ -71,6 +73,7 @@ def session_decorator(
             name=name,
             venv_backend=venv_backend,
             venv_params=venv_params,
+            tags=tags,
         )
 
     if py is not None and python is not None:
@@ -82,7 +85,7 @@ def session_decorator(
     if python is None:
         python = py
 
-    fn = Func(func, python, reuse_venv, name, venv_backend, venv_params)
+    fn = Func(func, python, reuse_venv, name, venv_backend, venv_params, tags=tags)
     _REGISTRY[name or func.__name__] = fn
     return fn
 

nox/sessions.py

@@ -657,6 +657,10 @@ class SessionRunner:
     def friendly_name(self) -> str:
         return self.signatures[0] if self.signatures else self.name
 
+    @property
+    def tags(self) -> list[str]:
+        return self.func.tags
+
     @property
     def envdir(self) -> str:
         return _normalize_path(self.global_config.envdir, self.friendly_name)

nox/tasks.py

@@ -191,6 +191,13 @@ def filter_manifest(manifest: Manifest, global_config: Namespace) -> Manifest |
             logger.error("Python version selection caused no sessions to be selected.")
             return 3
 
+    # Filter by tags.
+    if global_config.tags is not None:
+        manifest.filter_by_tags(global_config.tags)
+        if not manifest and not global_config.list_sessions:
+            logger.error("Tag selection caused no sessions to be selected.")
+            return 3
+
     # Filter by keywords.
     if global_config.keywords:
         try:

tests/test_manifest.py

@@ -33,8 +33,13 @@ from nox.manifest import (
 
 def create_mock_sessions():
     sessions = collections.OrderedDict()
-    sessions["foo"] = mock.Mock(spec=(), python=None, venv_backend=None)
-    sessions["bar"] = mock.Mock(spec=(), python=None, venv_backend=None)
+    sessions["foo"] = mock.Mock(spec=(), python=None, venv_backend=None, tags=["baz"])
+    sessions["bar"] = mock.Mock(
+        spec=(),
+        python=None,
+        venv_backend=None,
+        tags=["baz", "qux"],
+    )
     return sessions
 
 
@@ -190,6 +195,27 @@ def test_filter_by_keyword():
     assert len(manifest) == 2
     manifest.filter_by_keywords("foo")
     assert len(manifest) == 1
+    # Match tags
+    manifest.filter_by_keywords("not baz")
+    assert len(manifest) == 0
+
+
+@pytest.mark.parametrize(
+    "tags,session_count",
+    [
+        (["baz", "qux"], 2),
+        (["baz"], 2),
+        (["qux"], 1),
+        (["missing"], 0),
+        (["baz", "missing"], 2),
+    ],
+)
+def test_filter_by_tags(tags: list[str], session_count: int):
+    sessions = create_mock_sessions()
+    manifest = Manifest(sessions, create_mock_config())
+    assert len(manifest) == 2
+    manifest.filter_by_tags(tags)
+    assert len(manifest) == session_count
 
 
 def test_list_all_sessions_with_filter():

tests/test_registry.py

@@ -60,6 +60,14 @@ def test_session_decorator_list_of_pythons(cleanup_registry):
     assert unit_tests.python == ["3.5", "3.6"]
 
 
+def test_session_decorator_tags(cleanup_registry):
+    @registry.session_decorator(tags=["tag-1", "tag-2"])
+    def unit_tests(session):
+        pass
+
+    assert unit_tests.tags == ["tag-1", "tag-2"]
+
+
 def test_session_decorator_py_alias(cleanup_registry):
     @registry.session_decorator(py=["3.5", "3.6"])
     def unit_tests(session):

tests/test_tasks.py

@@ -39,6 +39,7 @@ def session_func():
 session_func.python = None
 session_func.venv_backend = None
 session_func.should_warn = dict()
+session_func.tags = []
 
 
 def session_func_with_python():
@@ -243,6 +244,77 @@ def test_filter_manifest_keywords_syntax_error():
     assert return_value == 3
 
 
+@pytest.mark.parametrize(
+    "tags,session_count",
+    [
+        (None, 4),
+        (["foo"], 3),
+        (["bar"], 3),
+        (["baz"], 1),
+        (["foo", "bar"], 4),
+        (["foo", "baz"], 3),
+        (["foo", "bar", "baz"], 4),
+    ],
+)
+def test_filter_manifest_tags(tags, session_count):
+    @nox.session(tags=["foo"])
+    def qux():
+        pass
+
+    @nox.session(tags=["bar"])
+    def quux():
+        pass
+
+    @nox.session(tags=["foo", "bar"])
+    def quuz():
+        pass
+
+    @nox.session(tags=["foo", "bar", "baz"])
+    def corge():
+        pass
+
+    config = _options.options.namespace(
+        sessions=None, pythons=(), posargs=[], tags=tags
+    )
+    manifest = Manifest(
+        {
+            "qux": qux,
+            "quux": quux,
+            "quuz": quuz,
+            "corge": corge,
+        },
+        config,
+    )
+    return_value = tasks.filter_manifest(manifest, config)
+    assert return_value is manifest
+    assert len(manifest) == session_count
+
+
+@pytest.mark.parametrize(
+    "tags",
+    [
+        ["Foo"],
+        ["not-found"],
+    ],
+    ids=[
+        "tags-are-case-insensitive",
+        "tag-does-not-exist",
+    ],
+)
+def test_filter_manifest_tags_not_found(tags, caplog):
+    @nox.session(tags=["foo"])
+    def quux():
+        pass
+
+    config = _options.options.namespace(
+        sessions=None, pythons=(), posargs=[], tags=tags
+    )
+    manifest = Manifest({"quux": quux}, config)
+    return_value = tasks.filter_manifest(manifest, config)
+    assert return_value == 3
+    assert "Tag selection caused no sessions to be selected." in caplog.text
+
+
 def test_honor_list_request_noop():
     config = _options.options.namespace(list_sessions=False)
     manifest = {"thing": mock.sentinel.THING}