Replace pkg_resources.parse_version with packaging.version.parse (#3693)

pip/commands/search.py

@@ -11,6 +11,7 @@
 from pip.utils.logging import indent_log
 from pip.exceptions import CommandError
 from pip.status_codes import NO_MATCHES_FOUND
+from pip._vendor.packaging.version import parse as parse_version
 from pip._vendor import pkg_resources
 from pip._vendor.six.moves import xmlrpc_client
 
@@ -140,6 +141,4 @@ def print_results(hits, name_column_width=None, terminal_width=None):
 
 
 def highest_version(versions):
-    return next(iter(
-        sorted(versions, key=pkg_resources.parse_version, reverse=True)
-    ))
+    return max(versions, key=parse_version)

pip/req/req_install.py

@@ -19,7 +19,7 @@
 from pip._vendor.packaging.markers import Marker
 from pip._vendor.packaging.requirements import InvalidRequirement, Requirement
 from pip._vendor.packaging.utils import canonicalize_name
-from pip._vendor.packaging.version import Version
+from pip._vendor.packaging.version import Version, parse as parse_version
 from pip._vendor.six.moves import configparser
 
 import pip.wheel
@@ -425,9 +425,7 @@ def run_egg_info(self):
                 command_desc='python setup.py egg_info')
 
         if not self.req:
-            if isinstance(
-                    pkg_resources.parse_version(self.pkg_info()["Version"]),
-                    Version):
+            if isinstance(parse_version(self.pkg_info()["Version"]), Version):
                 op = "=="
             else:
                 op = "==="