# HG changeset patch
# User Marcin Kuzminski <marcin@python-works.com>
# Date 2013-02-19 20:47:55
# Node ID 934f1fd5d5496f44848ab2cfc62d0fe80af01a34
# Parent  d21c762f5c4b3766a460a79c905b3aaebf81d601

rev_start for compare should use parents only if there are present

diff --git a/rhodecode/controllers/compare.py b/rhodecode/controllers/compare.py
--- a/rhodecode/controllers/compare.py
+++ b/rhodecode/controllers/compare.py
@@ -41,6 +41,7 @@ from rhodecode.model.db import Repositor
 from rhodecode.model.pull_request import PullRequestModel
 from webob.exc import HTTPBadRequest
 from rhodecode.lib.diffs import LimitedDiffContainer
+from rhodecode.lib.vcs.backends.base import EmptyChangeset
 
 log = logging.getLogger(__name__)
 
@@ -136,7 +137,7 @@ class CompareController(BaseRepoControll
             # get parent of
             # rev start to include it in the diff
             _cs = other_repo.scm_instance.get_changeset(rev_start)
-            rev_start = _cs.parents[0].raw_id
+            rev_start = _cs.parents[0].raw_id if _cs.parents else EmptyChangeset()
             org_ref = ('rev', rev_start)
             other_ref = ('rev', rev_end)
             #if we cherry pick it's not remote, make the other_repo org_repo