types: Mark 'Consistency' as a 'FastEnum'

This allows for stronger guarantees when checking the level of
consistency since it will only be comparable with itself, and ensures
unicity

1 files changed, 11 insertions, 1 deletions

diff --git a/src/buildstream/types.py b/src/buildstream/types.py
index dc40bd16f..56f5b99f0 100644
--- a/src/buildstream/types.py
+++ b/src/buildstream/types.py
@@ -104,7 +104,7 @@ class Scope(FastEnum):
     """
 
 
-class Consistency():
+class Consistency(FastEnum):
     """Defines the various consistency states of a :class:`.Source`.
     """
 
@@ -128,6 +128,16 @@ class Consistency():
     Sources have a cached unstaged copy in the source directory.
     """
 
+    def __ge__(self, other):
+        if self.__class__ is not other.__class__:
+            raise ValueError("Unexpected comparison between {} and {}".format(self, repr(other)))
+        return self.value >= other.value
+
+    def __lt__(self, other):
+        if self.__class__ is not other.__class__:
+            raise ValueError("Unexpected comparison between {} and {}".format(self, repr(other)))
+        return self.value < other.value
+
 
 class CoreWarnings():
     """CoreWarnings()