diff -r 2cd93a8d4bde -r 4a2466b2a434 mercurial/revlogutils/deltas.py
--- a/mercurial/revlogutils/deltas.py	Tue Sep 18 16:18:37 2018 -0700
+++ b/mercurial/revlogutils/deltas.py	Tue Sep 18 16:24:36 2018 -0700
@@ -33,8 +33,6 @@
     mdiff,
 )
 
-CensoredNodeError = error.CensoredNodeError
-
 # maximum <delta-chain-data>/<revision-text-length> ratio
 LIMIT_DELTA2TEXT = 2
 
@@ -460,7 +458,7 @@
             revlog.checkhash(fulltext, expectednode, p1=p1, p2=p2)
         if flags & REVIDX_ISCENSORED:
             raise error.RevlogError(_('node %s is not censored') % expectednode)
-    except CensoredNodeError:
+    except error.CensoredNodeError:
         # must pass the censored index flag to add censored revisions
         if not flags & REVIDX_ISCENSORED:
             raise