Use a monotonic time for registry cache.

So an old cache does not take precedence over a newly set value.
I noticed this bug because of the time going backward in tests
because of the time.time mock introduced in
dcf55cf6deb90f2498e53068175562aa36d315cc, but this may happen
in production systems too.

Also adds another deprecation warning for python < 3.3.

setup.py

@@ -267,5 +267,10 @@ if sys.version_info < (3, 0):
             'bug at <https://github.com/ProgVal/Limnoria/issues> and we\'ll '
             'see together what we can do about it.',
             DeprecationWarning)
+if sys.version_info < (3, 3):
+    warnings.warn('You are installing Limnoria for Python < 3.3, which is '
+            'only partially support. Limnoria requires Python 3.4 or later '
+            'to be fully stable.',
+            DeprecationWarning)
 
 # vim:set shiftwidth=4 softtabstop=4 expandtab textwidth=79:

src/registry.py

@@ -70,6 +70,12 @@ ENCODING = 'string_escape' if minisix.PY2 else 'unicode_escape'
 decoder = codecs.getdecoder(ENCODING)
 encoder = codecs.getencoder(ENCODING)
 
+if hasattr(time, 'monotonic'):
+    monotonic_time = time.monotonic
+else:
+    # fallback for python < 3.3
+    monotonic_time = time.time
+
 _cache = utils.InsensitivePreservingDict()
 _lastModified = 0
 def open_registry(filename, clear=False):
@@ -105,7 +111,7 @@ def open_registry(filename, clear=False):
         except ValueError:
             raise InvalidRegistryFile('Error unpacking line %r' % acc)
         _cache[key] = value
-    _lastModified = time.time()
+    _lastModified = monotonic_time()
     _fd.close()
 
 CONF_FILE_HEADER = """
@@ -435,7 +441,7 @@ class Value(Group):
         if self._name == 'unset':
             self._lastModified = 0
         self.__parent.setName(*args)
-        self._lastModified = time.time()
+        self._lastModified = monotonic_time()
 
     def set(self, s):
         """Override this with a function to convert a string to whatever type
@@ -456,7 +462,7 @@ class Value(Group):
         inherited=True means the value is inherited from the parent, so if
         the parent gets a new value, this group will get the new value as
         well."""
-        self._lastModified = time.time()
+        self._lastModified = monotonic_time()
         self.value = v
         if self._supplyDefault:
             for (name, child) in list(self._children.items()):

src/test.py

@@ -87,7 +87,6 @@ def timeFastForward(extra_offset):
     mock_time_offset += extra_offset
 
 def setupMockTime():
-    mock_time_offset = 0
     time.time = mockTime
 
 def teardownMockTime():