feat: add session sync for uv

docs/tutorial.rst

@@ -252,6 +252,32 @@ You can also pass environment variables:
 See :func:`nox.sessions.Session.run` for more options and examples for running
 programs.
 
+Using uv to manage your project
+-------------------------------
+
+While the ``session.run_install`` can use ``uv`` as backend, it is also
+possible to sync your project with ``session.sync()``. Nox will handle
+the virtual env for you.
+
+A sync will not remove extraneous packages present in the environment.
+
+.. code-block:: python
+
+    @nox.session
+    def tests(session):
+        session.sync()
+        session.install("pytest")
+        session.run("pytest")
+
+If you work with workspaces, install only given packages.
+
+.. code-block:: python
+
+    @nox.session
+    def tests(session):
+        session.sync(package="mypackage")
+        session.run("mypackage")
+
 Selecting which sessions to run
 -------------------------------
 

nox/sessions.py

@@ -36,6 +36,7 @@
 from typing import (
     TYPE_CHECKING,
     Any,
+    Literal,
     NoReturn,
 )
 
@@ -713,7 +714,7 @@ def install(
         *args: str,
         env: Mapping[str, str] | None = None,
         include_outer_env: bool = True,
-        silent: bool | None = None,
+        silent: bool = True,
         success_codes: Iterable[int] | None = None,
         log: bool = True,
         external: ExternalType | None = None,
@@ -781,9 +782,6 @@ def install(
         if self._runner.global_config.no_install and venv._reused:
             return
 
-        if silent is None:
-            silent = True
-
         if isinstance(venv, VirtualEnv) and venv.venv_backend == "uv":
             cmd = ["uv", "pip", "install"]
         else:
@@ -803,6 +801,98 @@ def install(
             terminate_timeout=terminate_timeout,
         )
 
+    def sync(
+        self,
+        *args: str,
+        packages: Iterable[str] | None = None,
+        extras: Iterable[str] | Literal["all"] | None = None,
+        inexact: bool = True,
+        frozen: bool = True,
+        omit: Literal["dev", "non-dev"] | None = None,
+        env: Mapping[str, str] | None = None,
+        include_outer_env: bool = True,
+        silent: bool = True,
+        success_codes: Iterable[int] | None = None,
+        log: bool = True,
+        external: ExternalType | None = None,
+        stdout: int | IO[str] | None = None,
+        stderr: int | IO[str] | None = subprocess.STDOUT,
+        interrupt_timeout: float | None = DEFAULT_INTERRUPT_TIMEOUT,
+        terminate_timeout: float | None = DEFAULT_TERMINATE_TIMEOUT,
+    ) -> None:
+        """Install invokes `uv`_ to sync packages inside of the session's
+        virtualenv.
+
+        :param packages: Sync for a specific package in the workspace.
+        :param extras: Include optional dependencies from the extra group name.
+        :param inexact: Do not remove extraneous packages present in the environment. ``True`` by default.
+        :param frozen: Sync without updating the `uv.lock` file. ``True`` by default.
+        :param omit: Omit dependencies.
+
+        Additional keyword args are the same as for :meth:`run`.
+
+        .. note::
+
+           Other then ``uv pip``, ``uv sync`` did not automatically install
+           packages into the virtualenv directory. To do so, it's mandatory
+           to setup ``UV_PROJECT_ENVIRONMENT`` to the virtual env folder. This
+           will be done in the sync command.
+
+        .. _uv: https://docs.astral.sh/uv/concepts/projects
+        """
+        venv = self._runner.venv
+
+        if isinstance(venv, VirtualEnv) and venv.venv_backend == "uv":
+            overlay_env = env or {}
+            uv_venv = {"UV_PROJECT_ENVIRONMENT": venv.location}
+            env = {**uv_venv, **overlay_env}
+        elif not isinstance(venv, PassthroughEnv):
+            raise ValueError(
+                "A session without a uv environment can not install dependencies"
+                " with uv."
+            )
+
+        if self._runner.global_config.no_install and venv._reused:
+            return
+
+        cmd = ["uv", "sync"]
+
+        extraopts: list[str] = []
+        if isinstance(packages, list):
+            extraopts.extend(["--package", *packages])
+
+        if isinstance(extras, list):
+            extraopts.extend(["--extra", *extras])
+        elif extras == "all":
+            extraopts.append("--all-extras")
+
+        if frozen:
+            extraopts.append("--frozen")
+
+        if inexact:
+            extraopts.append("--inexact")
+
+        if omit == "dev":
+            extraopts.append("--no-dev")
+        elif omit == "non-dev":
+            extraopts.append("--only-dev")
+
+        self._run(
+            *cmd,
+            *args,
+            *extraopts,
+            env=env,
+            include_outer_env=include_outer_env,
+            external="error",
+            silent=silent,
+            success_codes=success_codes,
+            log=log,
+            stdout=stdout,
+            stderr=stderr,
+            interrupt_timeout=interrupt_timeout,
+            terminate_timeout=terminate_timeout,
+        )
+
     def notify(
         self,
         target: str | SessionRunner,

tests/test_sessions.py

@@ -928,6 +928,40 @@ class SessionNoSlots(nox.sessions.Session):
                 "urllib3",
             )
 
+    def test_sync_uv(self):
+        runner = nox.sessions.SessionRunner(
+            name="test",
+            signatures=["test"],
+            func=mock.sentinel.func,
+            global_config=_options.options.namespace(posargs=[]),
+            manifest=mock.create_autospec(nox.manifest.Manifest),
+        )
+        runner.venv = mock.create_autospec(nox.virtualenv.VirtualEnv)
+        runner.venv.env = {}
+        runner.venv.venv_backend = "uv"
+        runner.venv.location = "/project/.nox"
+
+        class SessionNoSlots(nox.sessions.Session):
+            pass
+
+        session = SessionNoSlots(runner=runner)
+
+        with mock.patch.object(session, "_run", autospec=True) as run:
+            session.sync(packages=["myproject"], silent=False)
+            run.assert_called_once_with(
+                "uv",
+                "sync",
+                "--package",
+                "myproject",
+                "--frozen",
+                "--inexact",
+                **_run_with_defaults(
+                    silent=False,
+                    external="error",
+                    env={"UV_PROJECT_ENVIRONMENT": "/project/.nox"},
+                ),
+            )
+
     def test___slots__(self):
         session, _ = self.make_session_and_runner()
         with pytest.raises(AttributeError):