# HG changeset patch
# User Boris Feld <boris.feld@octobus.net>
# Date 1497552007 -7200
# Node ID fb33d856d25e44c5c6122b4c7ec9251841af8cf5
# Parent  1991935fb603637e8c4be7f7ec3668d12d1162fc
compat: make obshistory._getdifflines compatible with mercurial 4.1

On Mercurial version 4.1 and lower, patch.diff seems to returns an empty list
when there is no change. Mercurial 4.2 returns None so we add a if for this
case.

diff -r 1991935fb603 -r fb33d856d25e hgext3rd/evolve/obshistory.py
--- a/hgext3rd/evolve/obshistory.py	Fri Jun 09 00:52:54 2017 +0100
+++ b/hgext3rd/evolve/obshistory.py	Thu Jun 15 20:40:07 2017 +0200
@@ -484,6 +484,9 @@
 def _getdifflines(iterdiff):
     """return a cleaned up lines"""
     try:
+        # XXX-COMPAT Mercurial 4.1 compat
+        if isinstance(iterdiff, list) and len(iterdiff) == 0:
+            return None
         lines = iterdiff.next()
     except StopIteration:
         return None