Merge "use sha1 hashes to sort constraints"

openstack_requirements/cmds/generate.py

@@ -14,10 +14,12 @@
 from __future__ import print_function
 
 import copy
+import hashlib
 import optparse
 import os.path
 import subprocess
 import sys
+import textwrap
 
 import fixtures
 
@@ -188,6 +190,19 @@ def _parse_blacklist(path):
         return [l.strip() for l in f]
 
 
+def _make_sort_key(line):
+    """Produce a key that is unlikely to place similar values together.
+
+    We want to avoid sorting all of the oslo libraries together (or
+    all of the python-*client libraries) so when we do batch releases
+    we do not have merge conflicts in the individual patches updating
+    the constraints.
+
+    """
+    dep = line.partition('=')[0].encode('utf-8')
+    return hashlib.sha1(dep).digest()
+
+
 def main(argv=None, stdout=None):
     parser = optparse.OptionParser()
     parser.add_option(
@@ -214,5 +229,12 @@ def main(argv=None, stdout=None):
         _freeze(options.requirements, python) for python in options.pythons]
     _clone_versions(freezes, options)
     blacklist = _parse_blacklist(options.blacklist)
-    stdout.writelines(_combine_freezes(freezes, blacklist))
+    stdout.write(textwrap.dedent('''\
+    # This file is automatically generated using a sort order
+    # intended to reduce collisions when individual lines are
+    # updated in separate patches.
+    #
+    '''))
+    frozen = sorted(_combine_freezes(freezes, blacklist), key=_make_sort_key)
+    stdout.writelines(frozen)
     stdout.flush()