mercurial/hook.py

--- a/mercurial/hook.py	Sat Oct 17 01:15:34 2015 +0900
+++ b/mercurial/hook.py	Sat Oct 17 01:15:34 2015 +0900
@@ -118,6 +118,13 @@
 
     starttime = time.time()
     env = {}
+
+    # make in-memory changes visible to external process
+    tr = repo.currenttransaction()
+    repo.dirstate.write(tr)
+    if tr and tr.writepending():
+        env['HG_PENDING'] = repo.root
+
     for k, v in args.iteritems():
         if callable(v):
             v = v()