1 files changed, 9 insertions, 1 deletions
diff --git a/lib/gitlab/github_import/pull_request_formatter.rb b/lib/gitlab/github_import/pull_request_formatter.rb
index 4ea0200e89b..28812fd0cb9 100644
--- a/lib/gitlab/github_import/pull_request_formatter.rb
+++ b/lib/gitlab/github_import/pull_request_formatter.rb
@@ -38,7 +38,11 @@ module Gitlab
 
       def source_branch_name
         @source_branch_name ||= begin
-          source_branch_exists? ? source_branch_ref : "pull/#{number}/#{source_branch_ref}"
+          if cross_project?
+            "pull/#{number}/#{source_branch_repo.full_name}/#{source_branch_ref}"
+          else
+            source_branch_exists? ? source_branch_ref : "pull/#{number}/#{source_branch_ref}"
+          end
         end
       end
 
@@ -52,6 +56,10 @@ module Gitlab
         end
       end
 
+      def cross_project?
+        source_branch.repo.id != target_branch.repo.id
+      end
+
       private
 
       def state