diff -r 37b82485097f -r 31a2eb0f74e5 mercurial/ui.py
--- a/mercurial/ui.py	Wed Aug 30 16:05:12 2017 -0700
+++ b/mercurial/ui.py	Wed Aug 30 14:04:55 2017 -0700
@@ -962,6 +962,7 @@
             # formatted() will need some adjustment.
             or not self.formatted()
             or self.plain()
+            or self._buffers
             # TODO: expose debugger-enabled on the UI object
             or '--debugger' in pycompat.sysargv):
             # We only want to paginate if the ui appears to be