Don't suggest --user in virtual environment

Author: uranusjr

news/9409.bugfix.rst

@@ -0,0 +1,2 @@
+``--user`` is no longer suggested incorrectly when pip fails with a permission
+error in a virtual environment.

src/pip/_internal/commands/install.py

@@ -31,7 +31,10 @@
     write_output,
 )
 from pip._internal.utils.temp_dir import TempDirectory
-from pip._internal.utils.virtualenv import virtualenv_no_global
+from pip._internal.utils.virtualenv import (
+    running_under_virtualenv,
+    virtualenv_no_global,
+)
 from pip._internal.wheel_builder import (
     BinaryAllowedPredicate,
     build,
@@ -714,7 +717,7 @@ def create_os_error_message(error, show_traceback, using_user_site):
         user_option_part = "Consider using the `--user` option"
         permissions_part = "Check the permissions"
 
-        if not using_user_site:
+        if not running_under_virtualenv() and not using_user_site:
             parts.extend([
                 user_option_part, " or ",
                 permissions_part.lower(),

tests/unit/test_command_install.py

@@ -4,6 +4,7 @@
 import pytest
 from pip._vendor.packaging.requirements import Requirement
 
+from pip._internal.commands import install
 from pip._internal.commands.install import (
     create_os_error_message,
     decide_user_install,
@@ -109,7 +110,8 @@ def test_rejection_for_location_requirement_options():
         ' permissions.\n'),
 ])
 def test_create_os_error_message(
-    error, show_traceback, using_user_site, expected
+    monkeypatch, error, show_traceback, using_user_site, expected
 ):
+    monkeypatch.setattr(install, "running_under_virtualenv", lambda: False)
     msg = create_os_error_message(error, show_traceback, using_user_site)
     assert msg == expected