--- a/mercurial/filelog.py	Thu Jul 19 09:57:42 2018 +0200
+++ b/mercurial/filelog.py	Thu Jul 19 10:06:58 2018 +0200
@@ -215,12 +215,12 @@
         self._revlog._lazydeltabase = value
 
     @property
-    def _aggressivemergedeltas(self):
-        return self._revlog._aggressivemergedeltas
+    def _deltabothparents(self):
+        return self._revlog._deltabothparents
 
-    @_aggressivemergedeltas.setter
-    def _aggressivemergedeltas(self, value):
-        self._revlog._aggressivemergedeltas = value
+    @_deltabothparents.setter
+    def _deltabothparents(self, value):
+        self._revlog._deltabothparents = value
 
     @property
     def _inline(self):

--- a/mercurial/localrepo.py	Thu Jul 19 09:57:42 2018 +0200
+++ b/mercurial/localrepo.py	Thu Jul 19 10:06:58 2018 +0200
@@ -669,9 +669,9 @@
         if manifestcachesize is not None:
             self.svfs.options['manifestcachesize'] = manifestcachesize
         # experimental config: format.aggressivemergedeltas
-        aggressivemergedeltas = self.ui.configbool('format',
-                                                   'aggressivemergedeltas')
-        self.svfs.options['aggressivemergedeltas'] = aggressivemergedeltas
+        deltabothparents = self.ui.configbool('format',
+                                              'aggressivemergedeltas')
+        self.svfs.options['deltabothparents'] = deltabothparents
         self.svfs.options['lazydeltabase'] = not scmutil.gddeltaconfig(self.ui)
         chainspan = self.ui.configbytes('experimental', 'maxdeltachainspan')
         if 0 <= chainspan:

--- a/mercurial/revlog.py	Thu Jul 19 09:57:42 2018 +0200
+++ b/mercurial/revlog.py	Thu Jul 19 10:06:58 2018 +0200
@@ -628,7 +628,7 @@
                 parents = [p for p in (p1r, p2r)
                            if p != nullrev and p not in tested]
 
-                if not revlog._aggressivemergedeltas and len(parents) == 2:
+                if not revlog._deltabothparents and len(parents) == 2:
                     parents.sort()
                     # To minimize the chance of having to build a fulltext,
                     # pick first whichever parent is closest to us (max rev)
@@ -915,7 +915,7 @@
         # How much data to read and cache into the raw revlog data cache.
         self._chunkcachesize = 65536
         self._maxchainlen = None
-        self._aggressivemergedeltas = True
+        self._deltabothparents = True
         self.index = []
         # Mapping of partial identifiers to full nodes.
         self._pcache = {}
@@ -945,8 +945,8 @@
                 self._chunkcachesize = opts['chunkcachesize']
             if 'maxchainlen' in opts:
                 self._maxchainlen = opts['maxchainlen']
-            if 'aggressivemergedeltas' in opts:
-                self._aggressivemergedeltas = opts['aggressivemergedeltas']
+            if 'deltabothparents' in opts:
+                self._deltabothparents = opts['deltabothparents']
             self._lazydeltabase = bool(opts.get('lazydeltabase', False))
             if 'compengine' in opts:
                 self._compengine = opts['compengine']
@@ -2843,7 +2843,7 @@
     DELTAREUSEALL = {'always', 'samerevs', 'never', 'fulladd'}
 
     def clone(self, tr, destrevlog, addrevisioncb=None,
-              deltareuse=DELTAREUSESAMEREVS, aggressivemergedeltas=None):
+              deltareuse=DELTAREUSESAMEREVS, deltabothparents=None):
         """Copy this revlog to another, possibly with format changes.
 
         The destination revlog will contain the same revisions and nodes.
@@ -2877,7 +2877,7 @@
         deltas will be recomputed if the delta's parent isn't a parent of the
         revision.
 
-        In addition to the delta policy, the ``aggressivemergedeltas`` argument
+        In addition to the delta policy, the ``deltabothparents`` argument
         controls whether to compute deltas against both parents for merges.
         By default, the current default is used.
         """
@@ -2894,7 +2894,7 @@
 
         # lazydeltabase controls whether to reuse a cached delta, if possible.
         oldlazydeltabase = destrevlog._lazydeltabase
-        oldamd = destrevlog._aggressivemergedeltas
+        oldamd = destrevlog._deltabothparents
 
         try:
             if deltareuse == self.DELTAREUSEALWAYS:
@@ -2902,7 +2902,7 @@
             elif deltareuse == self.DELTAREUSESAMEREVS:
                 destrevlog._lazydeltabase = False
 
-            destrevlog._aggressivemergedeltas = aggressivemergedeltas or oldamd
+            destrevlog._deltabothparents = deltabothparents or oldamd
 
             populatecachedelta = deltareuse in (self.DELTAREUSEALWAYS,
                                                 self.DELTAREUSESAMEREVS)
@@ -2957,4 +2957,4 @@
                     addrevisioncb(self, rev, node)
         finally:
             destrevlog._lazydeltabase = oldlazydeltabase
-            destrevlog._aggressivemergedeltas = oldamd
+            destrevlog._deltabothparents = oldamd

--- a/mercurial/upgrade.py	Thu Jul 19 09:57:42 2018 +0200
+++ b/mercurial/upgrade.py	Thu Jul 19 10:06:58 2018 +0200
@@ -455,7 +455,7 @@
         #reverse of "/".join(("data", path + ".i"))
         return filelog.filelog(repo.svfs, path[5:-2])
 
-def _copyrevlogs(ui, srcrepo, dstrepo, tr, deltareuse, aggressivemergedeltas):
+def _copyrevlogs(ui, srcrepo, dstrepo, tr, deltareuse, deltabothparents):
     """Copy revlogs between 2 repos."""
     revcount = 0
     srcsize = 0
@@ -579,7 +579,7 @@
         ui.note(_('cloning %d revisions from %s\n') % (len(oldrl), unencoded))
         oldrl.clone(tr, newrl, addrevisioncb=oncopiedrevision,
                     deltareuse=deltareuse,
-                    aggressivemergedeltas=aggressivemergedeltas)
+                    deltabothparents=deltabothparents)
 
         datasize = 0
         idx = newrl.index