# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@octobus.net>
# Date 1494608653 -7200
# Node ID fed22455e5105ff2349b707ae6c6a79f13fd7b4f
# Parent  393cbaf0d2943f2ab481244d6b05bfbbfac86b0f
obscache: use 'nullid' as the hash of an empty obsstore

This align this result with what we use for 'emptykey'

diff --git a/hgext3rd/evolve/obscache.py b/hgext3rd/evolve/obscache.py
--- a/hgext3rd/evolve/obscache.py
+++ b/hgext3rd/evolve/obscache.py
@@ -79,7 +79,12 @@
             except (OSError, IOError) as e:
                 if e.errno != errno.ENOENT:
                     raise
-            key = hashlib.sha1(keydata).digest()
+            if keydata:
+                key = hashlib.sha1(keydata).digest()
+            else:
+                # reusing an existing "empty" value make it easier to define a
+                # default cachekey for 'no data'.
+                key = node.nullid
             return obsstoresize, key
 
     obsstore.__class__ = cachekeyobsstore