diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -113,6 +113,9 @@ coreconfigitem('format', 'chunkcachesize
 coreconfigitem('format', 'dotencode',
     default=True,
 )
+coreconfigitem('format', 'generaldelta',
+    default=False,
+)
 coreconfigitem('hostsecurity', 'ciphers',
     default=None,
 )
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -982,14 +982,14 @@ def gdinitconfig(ui):
     """helper function to know if a repo should be created as general delta
     """
     # experimental config: format.generaldelta
-    return (ui.configbool('format', 'generaldelta', False)
+    return (ui.configbool('format', 'generaldelta')
             or ui.configbool('format', 'usegeneraldelta', True))
 
 def gddeltaconfig(ui):
     """helper function to know if incoming delta should be optimised
     """
     # experimental config: format.generaldelta
-    return ui.configbool('format', 'generaldelta', False)
+    return ui.configbool('format', 'generaldelta')
 
 class simplekeyvaluefile(object):
     """A simple file with key=value lines