diff --git a/rhodecode/model/pull_request.py b/rhodecode/model/pull_request.py
--- a/rhodecode/model/pull_request.py
+++ b/rhodecode/model/pull_request.py
@@ -39,7 +39,6 @@ from rhodecode.lib.utils2 import safe_un
 
 from rhodecode.lib.vcs.utils.hgcompat import scmutil
 from rhodecode.lib.vcs.utils import safe_str
-from rhodecode.lib.vcs.backends.base import EmptyChangeset
 
 log = logging.getLogger(__name__)
 
@@ -186,18 +185,13 @@ class PullRequestModel(BaseModel):
 
             org_rev_spec = "%s('%s')" % (_revset_predicates[org_ref[0]],
                                          safe_str(org_ref[1]))
-            if org_ref[1] == EmptyChangeset().raw_id:
-                org_rev = org_ref[1]
-            else:
-                org_rev = org_repo._repo[scmutil.revrange(org_repo._repo,
-                                                          [org_rev_spec])[-1]]
+            org_rev = org_repo._repo[scmutil.revrange(org_repo._repo,
+                                                      [org_rev_spec])[-1]]
+
             other_rev_spec = "%s('%s')" % (_revset_predicates[other_ref[0]],
                                            safe_str(other_ref[1]))
-            if other_ref[1] == EmptyChangeset().raw_id:
-                other_rev = other_ref[1]
-            else:
-                other_rev = other_repo._repo[scmutil.revrange(other_repo._repo,
-                                                        [other_rev_spec])[-1]]
+            other_rev = other_repo._repo[scmutil.revrange(other_repo._repo,
+                                                          [other_rev_spec])[-1]]
 
             #case two independent repos
             if org_repo != other_repo: