fix intermittent failures with deferred version test

Need to get rid of the deferred string approach as
the problem was overriding string methods is hard and
flaky.  There is just no other documented
argparse hook to allow deferring of the version
calculation as version passed in has to be a str
or buffer. Added a test to try longer string and even
run it in a loop just to be sure.

Fixes LP #1087575

Change-Id: Icf83944d67b8ce5d3230627f3de10501da3276f2

1 files changed, 6 insertions, 35 deletions

diff --git a/openstack/common/version.py b/openstack/common/version.py
index dae88e3..2c11fbc 100644
--- a/openstack/common/version.py
+++ b/openstack/common/version.py
@@ -24,39 +24,6 @@ import pkg_resources
 import setup
 
 
-class _deferred_version_string(str):
-    """Internal helper class which provides delayed version calculation."""
-
-    def __new__(cls, version_info, prefix):
-        new_obj = str.__new__(cls, "")
-        new_obj._version_info = version_info
-        new_obj._prefix = prefix
-        new_obj._cached_version = None
-        return new_obj
-
-    def _get_cached_version(self):
-        if not self._cached_version:
-            self._cached_version = \
-                "%s%s" % (self._prefix,
-                self._version_info.version_string())
-        return self._cached_version
-
-    def __len__(self):
-        return self._get_cached_version().__len__()
-
-    def __contains__(self, item):
-        return self._get_cached_version().__contains__(item)
-
-    def __getslice__(self, i, j):
-        return self._get_cached_version().__getslice__(i, j)
-
-    def __str__(self):
-        return self._get_cached_version()
-
-    def __repr__(self):
-        return self._get_cached_version()
-
-
 class VersionInfo(object):
 
     def __init__(self, package, python_package=None, pre_version=None):
@@ -77,6 +44,7 @@ class VersionInfo(object):
             self.python_package = python_package
         self.pre_version = pre_version
         self.version = None
+        self._cached_version = None
 
     def _generate_version(self):
         """Defer to the openstack.common.setup routines for making a
@@ -158,11 +126,14 @@ class VersionInfo(object):
         else:
             return '%s-dev' % (version_parts[0],)
 
-    def deferred_version_string(self, prefix=""):
+    def cached_version_string(self, prefix=""):
         """Generate an object which will expand in a string context to
         the results of version_string(). We do this so that don't
         call into pkg_resources every time we start up a program when
         passing version information into the CONF constructor, but
         rather only do the calculation when and if a version is requested
         """
-        return _deferred_version_string(self, prefix)
+        if not self._cached_version:
+            self._cached_version = "%s%s" % (prefix,
+                                             self.version_string())
+        return self._cached_version