Fix in-site-packages patch for user install tests

Author: uranusjr

tests/functional/test_install_user.py

@@ -16,18 +16,15 @@
 def _patch_dist_in_site_packages(virtualenv: VirtualEnvironment) -> None:
     # Since the tests are run from a virtualenv, and to avoid the "Will not
     # install to the usersite because it will lack sys.path precedence..."
-    # error: Monkey patch `pip._internal.req.req_install.dist_in_site_packages`
-    # and `pip._internal.utils.misc.dist_in_site_packages`
-    # so it's possible to install a conflicting distribution in the user site.
+    # error: Monkey patch the Distribution class so it's possible to install a
+    # conflicting distribution in the user site.
     virtualenv.sitecustomize = textwrap.dedent(
         """
         def dist_in_site_packages(dist):
             return False
 
-        from pip._internal.req import req_install
-        from pip._internal.utils import misc
-        req_install.dist_in_site_packages = dist_in_site_packages
-        misc.dist_in_site_packages = dist_in_site_packages
+        from pip._internal.metadata.base import BaseDistribution
+        BaseDistribution.in_site_packages = property(dist_in_site_packages)
     """
     )
 

tests/functional/test_new_resolver_user.py

@@ -135,8 +135,8 @@ def patch_dist_in_site_packages(virtualenv: VirtualEnvironment) -> None:
         def dist_in_site_packages(dist):
             return False
 
-        from pip._internal.utils import misc
-        misc.dist_in_site_packages = dist_in_site_packages
+        from pip._internal.metadata.pkg_resources import Distribution
+        Distribution.in_site_packages = property(dist_in_site_packages)
     """
     )