# HG changeset patch
# User Augie Fackler <augie@google.com>
# Date 1439319227 14400
# Node ID 2c03e521a0c5defd1798bdbb0707d736db2e31fd
# Parent  bbb698697efc4ba9067e5db8a13b3c5e78632997
reachableroots: return NULL if we're throwing an exception

Based on my reading of [0] and surrounding sections, if we want an
exception to be properly raised when something goes wrong in the C
code, we need to make sure we return NULL here. Do so.

https://docs.python.org/2/extending/extending.html#back-to-the-example

diff -r bbb698697efc -r 2c03e521a0c5 mercurial/parsers.c
--- a/mercurial/parsers.c	Tue Aug 11 15:34:10 2015 -0400
+++ b/mercurial/parsers.c	Tue Aug 11 14:53:47 2015 -0400
@@ -1232,9 +1232,7 @@
 release_reachable:
 	Py_XDECREF(reachable);
 bail:
-	val = Py_None;
-	Py_INCREF(Py_None);
-	return val;
+	return NULL;
 }
 
 static PyObject *compute_phases_map_sets(indexObject *self, PyObject *args)