Percolate the verbose global option to the silent argument for session installation commands, and document it

docs/config.rst

@@ -512,6 +512,7 @@ The following options can be specified in the Noxfile:
 * ``nox.options.error_on_missing_interpreters`` is equivalent to specifying :ref:`--error-on-missing-interpreters <opt-error-on-missing-interpreters>`. You can force this off by specifying ``--no-error-on-missing-interpreters`` during invocation.
 * ``nox.options.error_on_external_run`` is equivalent to specifying :ref:`--error-on-external-run <opt-error-on-external-run>`. You can force this off by specifying ``--no-error-on-external-run`` during invocation.
 * ``nox.options.report`` is equivalent to specifying :ref:`--report <opt-report>`.
+* ``nox.options.verbose`` is equivalent to specifying :ref:`-v or --verbose <opt-verbose>`. You can force this off by specifying ``--no-verbose`` during invocation.
 
 
 When invoking ``nox``, any options specified on the command line take precedence over the options specified in the Noxfile. If either ``--sessions`` or ``--keywords`` is specified on the command line, *both* options specified in the Noxfile will be ignored.

docs/usage.rst

@@ -434,14 +434,18 @@ However, this will never output colorful logs:
     nox --nocolor
 
 
-.. _opt-report:
+.. _opt-verbose:
 
 
 Controlling commands verbosity
 ------------------------------
 
 By default, Nox will only show output of commands that fail, or, when the commands get passed ``silent=False``.
-By passing ``--verbose`` to Nox, all output of all commands run is shown, regardless of the silent argument.
+By either passing ``--verbose`` to Nox or setting ``nox.options.verbose = True``, all output of all commands
+run is shown, regardless of the silent argument.
+
+
+.. _opt-report:
 
 
 Outputting a machine-readable report

nox/_options.py

@@ -421,15 +421,12 @@ def _tag_completer(
         help="Arguments following ``--`` that are passed through to the session(s).",
         finalizer_func=_posargs_finalizer,
     ),
-    _option_set.Option(
+    *_option_set.make_flag_pair(
         "verbose",
-        "-v",
-        "--verbose",
+        ("-v", "--verbose"),
+        ("--no-verbose",),
         group=options.groups["reporting"],
-        action="store_true",
-        default=False,
         help="Logs the output of all commands run including commands marked silent.",
-        noxfile=True,
     ),
     _option_set.Option(
         "add_timestamp",

nox/sessions.py

@@ -728,7 +728,7 @@ def conda_install(
             args = _dblquote_pkg_install_args(args)
 
         if silent is None:
-            silent = True
+            silent = not self._runner.global_config.verbose
 
         extraopts: list[str] = []
         if auto_offline and venv.is_offline():
@@ -838,7 +838,7 @@ def install(
             return
 
         if silent is None:
-            silent = True
+            silent = not self._runner.global_config.verbose
 
         if isinstance(venv, VirtualEnv) and venv.venv_backend == "uv":
             cmd = ["uv", "pip", "install"]

tests/test_sessions.py

@@ -840,6 +840,80 @@ class SessionNoSlots(nox.sessions.Session):
         ):
             session.install("requests", "urllib3")
 
+    @pytest.mark.parametrize(
+        ("verbose", "expected_silent"),
+        [
+            (True, False),
+            (False, True),
+        ],
+    )
+    def test_install_verbose(self, verbose: bool, expected_silent: bool) -> None:
+        runner = nox.sessions.SessionRunner(
+            name="test",
+            signatures=["test"],
+            func=mock.sentinel.func,
+            global_config=_options.options.namespace(posargs=[], verbose=verbose),
+            manifest=mock.create_autospec(nox.manifest.Manifest),
+        )
+        runner.venv = make_fake_env()
+
+        class SessionNoSlots(nox.sessions.Session):
+            pass
+
+        session = SessionNoSlots(runner=runner)
+
+        with mock.patch.object(session, "_run", autospec=True) as run:
+            session.install("requests", "urllib3")
+            run.assert_called_once_with(
+                "python",
+                "-m",
+                "pip",
+                "install",
+                "requests",
+                "urllib3",
+                **_run_with_defaults(silent=expected_silent, external="error"),
+            )
+
+    @pytest.mark.parametrize(
+        ("verbose", "expected_silent"),
+        [
+            (True, False),
+            (False, True),
+        ],
+    )
+    def test_conda_install_verbose(self, verbose: bool, expected_silent: bool) -> None:
+        runner = nox.sessions.SessionRunner(
+            name="test",
+            signatures=["test"],
+            func=mock.sentinel.func,
+            global_config=_options.options.namespace(posargs=[], verbose=verbose),
+            manifest=mock.create_autospec(nox.manifest.Manifest),
+        )
+        runner.venv = mock.create_autospec(nox.virtualenv.CondaEnv)
+        assert runner.venv
+        runner.venv.location = "/path/to/conda/env"
+        runner.venv.env = {}
+        runner.venv.is_offline = lambda: False  # type: ignore[attr-defined]
+        runner.venv.conda_cmd = "conda"  # type: ignore[attr-defined]
+
+        class SessionNoSlots(nox.sessions.Session):
+            pass
+
+        session = SessionNoSlots(runner=runner)
+
+        with mock.patch.object(session, "_run", autospec=True) as run:
+            session.conda_install("requests", "urllib3")
+            run.assert_called_once_with(
+                "conda",
+                "install",
+                "--yes",
+                "--prefix",
+                "/path/to/conda/env",
+                "requests",
+                "urllib3",
+                **_run_with_defaults(silent=expected_silent, external="error"),
+            )
+
     def test_notify(self) -> None:
         session, runner = self.make_session_and_runner()