Try to fix some Python 3 issues.

Dunno what to do about the Mercurial/Bazaar test failures under it.

pip/index.py

@@ -110,9 +110,8 @@ def find_requirement(self, req, upgrade):
 
         # Assign a preference value to all index, mirror, or find_links
         # package sources. The lower the number, the higher the preference.
-        # Start at 1; if the desired version of a package is installed, it
-        # should win, so it's assigned a preference of zero.
-        origin_preferences = dict([(str(e[1]), e[0] + 1) for e in enumerate(all_index_urls + self.find_links)])
+        all_origins = reversed(all_index_urls + self.find_links)
+        origin_preferences = dict([(str(e[1]), e[0]) for e in enumerate(all_origins)])
         logger.debug('Origin preferences: %s' % origin_preferences)
 
         def mkurl_pypi_url(url):
@@ -172,15 +171,18 @@ def mkurl_pypi_url(url):
             found_versions = file_versions + found_versions
         all_versions = found_versions + page_versions + dependency_versions
         applicable_versions = []
+
+        highest_preference = float('inf')
+        lowest_preference = float('-inf')
         for (parsed_version, link, version) in all_versions:
             if version not in req.req:
                 logger.info("Ignoring link %s, version %s doesn't match %s"
                             % (link, version, ','.join([''.join(s) for s in req.req.specs])))
                 continue
-            preference = Inf
+            preference = lowest_preference
             if link is Inf:
                 # this version is currently installed; it wins.
-                preference = 0
+                preference = highest_preference
             else:
                 for origin in origin_preferences.keys():
                     link_url = link.comes_from and link.comes_from.url or link.url
@@ -189,7 +191,7 @@ def mkurl_pypi_url(url):
                         break
             applicable_versions.append((link, version, parsed_version, preference))
         # sort applicable_versions by origin preference
-        applicable_versions = sorted(applicable_versions, key=operator.itemgetter(3))
+        applicable_versions = sorted(applicable_versions, key=operator.itemgetter(3), reverse=True)
         # and then by version
         applicable_versions = sorted(applicable_versions, key=operator.itemgetter(2), reverse=True)
         existing_applicable = bool([link for link, version, parsed_version, preference in applicable_versions if link is Inf])
@@ -611,6 +613,18 @@ def __str__(self):
         else:
             return self.url
 
+    def __ge__(self, other):
+        return self.url >= other.url
+
+    def __gt__(self, other):
+        return self.url > other.url
+
+    def __le__(self, other):
+        return self.url <= other.url
+
+    def __lt__(self, other):
+        return self.url < other.url
+
     def __repr__(self):
         return '<Link %s>' % self
 

pip/util.py

@@ -132,6 +132,18 @@ def __cmp__(self, a):
             return 0
         return 1
 
+    def __ge__(self, a):
+        return True
+
+    def __gt__(self, a):
+        return True
+
+    def __le__(self, a):
+        return False
+
+    def __lt__(self, a):
+        return False
+
     def __repr__(self):
         return 'Inf'
 

tests/test_index_preference.py

@@ -2,7 +2,7 @@
 import re
 import shutil
 
-from test_pip import here, reset_env, run_pip
+from tests.test_pip import here, reset_env, run_pip
 
 
 def test_index_preference():