Merge pull request #8319 from uranusjr/fix-prefer-binary-reqfile-new-…

…resolver

src/pip/_internal/resolution/resolvelib/provider.py

@@ -6,8 +6,6 @@
 if MYPY_CHECK_RUNNING:
     from typing import Any, Dict, Optional, Sequence, Set, Tuple, Union
 
-    from pip._vendor.packaging.version import _BaseVersion
-
     from .base import Requirement, Candidate
     from .factory import Factory
 
@@ -90,17 +88,22 @@ def _eligible_for_upgrade(name):
             return False
 
         def sort_key(c):
-            # type: (Candidate) -> Tuple[int, _BaseVersion]
+            # type: (Candidate) -> int
             """Return a sort key for the matches.
 
             The highest priority should be given to installed candidates that
             are not eligible for upgrade. We use the integer value in the first
             part of the key to sort these before other candidates.
+
+            We only pull the installed candidate to the bottom (i.e. most
+            preferred), but otherwise keep the ordering returned by the
+            requirement. The requirement is responsible for returning a list
+            otherwise sorted for the resolver, taking account for versions
+            and binary preferences as specified by the user.
             """
             if c.is_installed and not _eligible_for_upgrade(c.name):
-                return (1, c.version)
-
-            return (0, c.version)
+                return 1
+            return 0
 
         return sorted(matches, key=sort_key)
 

tests/functional/test_download.py

@@ -669,7 +669,6 @@ def test_download_exit_status_code_when_blank_requirements_file(script):
     script.pip('download', '-r', 'blank.txt')
 
 
-@pytest.mark.fails_on_new_resolver
 def test_download_prefer_binary_when_tarball_higher_than_wheel(script, data):
     fake_wheel(data, 'source-0.8-py2.py3-none-any.whl')
     result = script.pip(