From 3fc6842fb8c6b5e928c5b65a3ccee9c2b3a68af6 Mon Sep 17 00:00:00 2001
From: Diego Ramirez <dr01191115@gmail.com>
Date: Thu, 24 Feb 2022 12:43:44 -0600
Subject: [PATCH 1/3] Disable running `session.install` outside a venv

---
 nox/sessions.py | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/nox/sessions.py b/nox/sessions.py
index 4bea8e8d..9291c287 100644
--- a/nox/sessions.py
+++ b/nox/sessions.py
@@ -532,6 +532,12 @@ def install(self, *args: str, **kwargs: Any) -> None:
             session.install('-e', '.')
 
         Additional keyword args are the same as for :meth:`run`.
+        
+        .. warning::
+
+            Running ``session.install`` without a virtual environment
+            is no longer supported. If you still want to do that, please
+            use ``session.run("pip", "install", ...)`` instead.
 
         .. _pip: https://pip.readthedocs.org
         """
@@ -544,13 +550,11 @@ def install(self, *args: str, **kwargs: Any) -> None:
                 "A session without a virtualenv can not install dependencies."
             )
         if isinstance(venv, PassthroughEnv):
-            warnings.warn(
+            raise ValueError (
                 f"Session {self.name} does not have a virtual environment, "
-                "so use of session.install() is deprecated since it would modify "
+                "so use of session.install() is no longer allowed since it would modify "
                 "the global Python environment. If you're really sure that is "
-                'what you want to do, use session.run("pip", "install", ...) instead.',
-                category=FutureWarning,
-                stacklevel=2,
+                'what you want to do, use session.run("pip", "install", ...) instead.'
             )
         if not args:
             raise ValueError("At least one argument required to install().")

From 635f20293546d6858a73178a2f3356d7aeb82892 Mon Sep 17 00:00:00 2001
From: Diego Ramirez <dr01191115@gmail.com>
Date: Thu, 24 Feb 2022 13:05:28 -0600
Subject: [PATCH 2/3] Fix linting

---
 nox/sessions.py | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/nox/sessions.py b/nox/sessions.py
index 9291c287..7391851e 100644
--- a/nox/sessions.py
+++ b/nox/sessions.py
@@ -22,7 +22,6 @@
 import re
 import sys
 import unicodedata
-import warnings
 from types import TracebackType
 from typing import Any, Callable, Iterable, Mapping, Sequence
 
@@ -532,7 +531,7 @@ def install(self, *args: str, **kwargs: Any) -> None:
             session.install('-e', '.')
 
         Additional keyword args are the same as for :meth:`run`.
-        
+
         .. warning::
 
             Running ``session.install`` without a virtual environment
@@ -550,11 +549,11 @@ def install(self, *args: str, **kwargs: Any) -> None:
                 "A session without a virtualenv can not install dependencies."
             )
         if isinstance(venv, PassthroughEnv):
-            raise ValueError (
-                f"Session {self.name} does not have a virtual environment, "
-                "so use of session.install() is no longer allowed since it would modify "
-                "the global Python environment. If you're really sure that is "
-                'what you want to do, use session.run("pip", "install", ...) instead.'
+            raise ValueError(
+                f"Session {self.name} does not have a virtual environment, so use of"
+                " session.install() is no longer allowed since it would modify the"
+                " global Python environment. If you're really sure that is what you"
+                ' want to do, use session.run("pip", "install", ...) instead.'
             )
         if not args:
             raise ValueError("At least one argument required to install().")

From 09f6c22ed8d2632374b461f2d4d1721a2fd1ec95 Mon Sep 17 00:00:00 2001
From: Diego Ramirez <dr01191115@gmail.com>
Date: Thu, 24 Feb 2022 13:16:26 -0600
Subject: [PATCH 3/3] Replace the old test by a new one (almost)

---
 tests/test_sessions.py | 29 +++++++++--------------------
 1 file changed, 9 insertions(+), 20 deletions(-)

diff --git a/tests/test_sessions.py b/tests/test_sessions.py
index 688b8f18..f7535958 100644
--- a/tests/test_sessions.py
+++ b/tests/test_sessions.py
@@ -646,7 +646,7 @@ class SessionNoSlots(nox.sessions.Session):
                 external="error",
             )
 
-    def test_install_no_venv_deprecated(self):
+    def test_install_no_venv_failure(self):
         runner = nox.sessions.SessionRunner(
             name="test",
             signatures=["test"],
@@ -662,25 +662,14 @@ class SessionNoSlots(nox.sessions.Session):
 
         session = SessionNoSlots(runner=runner)
 
-        with mock.patch.object(session, "_run", autospec=True) as run:
-            with pytest.warns(
-                FutureWarning,
-                match=(
-                    r"use of session\.install\(\) is deprecated since it would modify"
-                    r" the global Python environment"
-                ),
-            ):
-                session.install("requests", "urllib3")
-            run.assert_called_once_with(
-                "python",
-                "-m",
-                "pip",
-                "install",
-                "requests",
-                "urllib3",
-                silent=True,
-                external="error",
-            )
+        with pytest.raises(
+            ValueError,
+            match=(
+                r"use of session\.install\(\) is no longer allowed since"
+                r" it would modify the global Python environment"
+            ),
+        ):
+            session.install("requests", "urllib3")
 
     def test_notify(self):
         session, runner = self.make_session_and_runner()