diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -1366,7 +1366,8 @@ def gdinitconfig(ui):
     """
     # experimental config: format.generaldelta
     return (ui.configbool('format', 'generaldelta')
-            or ui.configbool('format', 'usegeneraldelta'))
+            or ui.configbool('format', 'usegeneraldelta')
+            or ui.configbool('format', 'sparse-revlog'))
 
 def gddeltaconfig(ui):
     """helper function to know if incoming delta should be optimised