diff --git a/pagure/internal/__init__.py b/pagure/internal/__init__.py
index cc5e53e..ed939e6 100644
--- a/pagure/internal/__init__.py
+++ b/pagure/internal/__init__.py
@@ -298,14 +298,21 @@ def get_pull_request_ready_branch():
                         com = main_walker.next()
                         main_commits.add(com.hex)
                     except StopIteration:
-                        pass
+                        com = None
                 try:
                     branch_commit = branch_walker.next()
                 except StopIteration:
                     branch_commit = None
 
-                if main_commits.intersection(set(
-                        branch_commits + [branch_commit.hex])):
+                # We sure never end up here but better safe than sorry
+                if com is None and branch_commit is None:
+                    break
+
+                if branch_commit:
+                    tmp = set(branch_commits + [branch_commit.hex])
+                else:
+                    tmp = set(branch_commits)
+                if main_commits.intersection(tmp):
                     break
                 branch_commits.append(branch_commit.hex)
 
diff --git a/pagure/lib/git.py b/pagure/lib/git.py
index adec451..bcc17cf 100644
--- a/pagure/lib/git.py
+++ b/pagure/lib/git.py
@@ -1379,13 +1379,19 @@ def diff_pull_request(
                 com = main_walker.next()
                 main_commits.add(com.hex)
             except StopIteration:
-                pass
+                com = None
+
             try:
                 branch_commit = branch_walker.next()
             except StopIteration:
                 branch_commit = None
 
-            branch_commits.add(branch_commit.oid.hex)
+            # We sure never end up here but better safe than sorry
+            if com is None and branch_commit is None:
+                break
+
+            if branch_commit:
+                branch_commits.add(branch_commit.oid.hex)
             if main_commits.intersection(branch_commits):
                 break
 
diff --git a/pagure/ui/fork.py b/pagure/ui/fork.py
index d22e1a3..1e8d0ce 100644
--- a/pagure/ui/fork.py
+++ b/pagure/ui/fork.py
@@ -98,13 +98,19 @@ def _get_pr_info(repo_obj, orig_repo, branch_from, branch_to):
                 com = main_walker.next()
                 main_commits.add(com.hex)
             except StopIteration:
-                pass
+                com = None
+
             try:
                 branch_commit = branch_walker.next()
             except StopIteration:
                 branch_commit = None
 
-            branch_commits.add(branch_commit.oid.hex)
+            # We sure never end up here but better safe than sorry
+            if com is None and branch_commit is None:
+                break
+
+            if branch_commit:
+                branch_commits.add(branch_commit.oid.hex)
             if main_commits.intersection(branch_commits):
                 break