diff --git a/mercurial/dispatch.py b/mercurial/dispatch.py
--- a/mercurial/dispatch.py
+++ b/mercurial/dispatch.py
@@ -181,7 +181,7 @@ def _runcatch(req):
                     debugtrace[debugger] == debugtrace['pdb']):
                     ui.warn(_("%s debugger specified "
                               "but its module was not found\n") % debugger)
-                with demandimport.disabled():
+                with demandimport.deactivated():
                     debugtrace[debugger]()
             try:
                 return _dispatch(req)