Merge pull request #42836 from lyft/backport-utils.versions-to-2016.11

Backport salt.utils.versions from develop to 2016.11

salt/utils/versions.py

@@ -0,0 +1,64 @@
+# -*- coding: utf-8 -*-
+'''
+    :copyright: Copyright 2017 by the SaltStack Team, see AUTHORS for more details.
+    :license: Apache 2.0, see LICENSE for more details.
+
+
+    salt.utils.versions
+    ~~~~~~~~~~~~~~~~~~~
+
+    Version parsing based on distutils.version which works under python 3
+    because on python 3 you can no longer compare strings against integers.
+'''
+
+# Import python libs
+from __future__ import absolute_import
+from distutils.version import StrictVersion as _StrictVersion
+from distutils.version import LooseVersion as _LooseVersion
+
+# Import 3rd-party libs
+from salt.ext import six
+
+
+class StrictVersion(_StrictVersion):
+    def parse(self, vstring):
+        _StrictVersion.parse(self, vstring)
+
+    def _cmp(self, other):
+        if isinstance(other, six.string_types):
+            other = StrictVersion(other)
+        return _StrictVersion._cmp(self, other)
+
+
+class LooseVersion(_LooseVersion):
+
+    def parse(self, vstring):
+        _LooseVersion.parse(self, vstring)
+
+        if six.PY3:
+            # Convert every part of the version to string in order to be able to compare
+            self._str_version = [
+                str(vp).zfill(8) if isinstance(vp, int) else vp for vp in self.version]
+
+    if six.PY3:
+        def _cmp(self, other):
+            if isinstance(other, six.string_types):
+                other = LooseVersion(other)
+
+            string_in_version = False
+            for part in self.version + other.version:
+                if not isinstance(part, int):
+                    string_in_version = True
+                    break
+
+            if string_in_version is False:
+                return _LooseVersion._cmp(self, other)
+
+            # If we reached this far, it means at least a part of the version contains a string
+            # In python 3, strings and integers are not comparable
+            if self._str_version == other._str_version:
+                return 0
+            if self._str_version < other._str_version:
+                return -1
+            if self._str_version > other._str_version:
+                return 1