diff -r 9a3e88d4a030 -r f40dc6f7c12f mercurial/extensions.py
--- a/mercurial/extensions.py	Mon May 22 00:51:56 2017 -0700
+++ b/mercurial/extensions.py	Mon May 22 01:17:49 2017 -0700
@@ -181,7 +181,7 @@
 
 def loadall(ui, whitelist=None):
     result = ui.configitems("extensions")
-    if whitelist:
+    if whitelist is not None:
         result = [(k, v) for (k, v) in result if k in whitelist]
     newindex = len(_order)
     for (name, path) in result: