--- a/mercurial/localrepo.py	Mon Jul 30 15:53:47 2018 +0200
+++ b/mercurial/localrepo.py	Tue Jul 31 13:53:06 2018 -0700
@@ -689,6 +689,8 @@
         self.svfs.options['sparse-read-min-gap-size'] = srmingapsize
         sparserevlog = SPARSEREVLOG_REQUIREMENT in self.requirements
         self.svfs.options['sparse-revlog'] = sparserevlog
+        if sparserevlog:
+            self.svfs.options['generaldelta'] = True
 
         for r in self.requirements:
             if r.startswith('exp-compression-'):