diff -r e5a1df51bb25 -r 9f272bf3b342 mercurial/hook.py
--- a/mercurial/hook.py	Tue Nov 03 12:31:33 2015 -0800
+++ b/mercurial/hook.py	Tue Nov 03 16:58:13 2015 -0800
@@ -122,7 +122,8 @@
     # make in-memory changes visible to external process
     tr = repo.currenttransaction()
     repo.dirstate.write(tr)
-    if tr and tr.writepending():
+    if tr:
+        tr.writepending()
         env['HG_PENDING'] = repo.root
 
     for k, v in args.iteritems():