filelog: stop proxying deltaparent() (API) deltaparent() obtains the revision number of the base revision a delta in storage is stored against. It is highly revlog-centric and may not apply to other storage backends. As a result, it doesn't belong on the generic file storage interface. This method/proxy is no longer used in core. The last consumer was probably changegroup code and went away with the transition to emitrevisions(). Differential Revision: https://phab.mercurial-scm.org/D4751

--- a/mercurial/filelog.py	Mon Sep 24 12:49:17 2018 -0700
+++ b/mercurial/filelog.py	Mon Sep 24 13:35:50 2018 -0700
@@ -67,9 +67,6 @@
     def children(self, node):
         return self._revlog.children(node)
 
-    def deltaparent(self, rev):
-        return self._revlog.deltaparent(rev)
-
     def iscensored(self, rev):
         return self._revlog.iscensored(rev)