Try if branch_exists? would work, feedback:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7237#note_18424135

Try if branch_exists? would work, feedback:
3e69c716 · Lin Jen-Shin · cd22fdd5 · 3e69c716
Commit 3e69c716 authored 8 years ago by Lin Jen-Shin
--- a/app/controllers/concerns/creates_commit.rb
+++ b/app/controllers/concerns/creates_commit.rb
@@ -4,7 +4,7 @@ module CreatesCommit
  def create_commit(service, success_path:, failure_path:, failure_view: nil, success_notice: nil)
    set_commit_variables
  
-    source_branch = @ref if @ref && @repository.find_branch(@ref)
+    source_branch = @ref if @ref && @repository.branch_exists?(@ref)
    commit_params = @commit_params.merge(
      source_project: @project,
      source_branch: source_branch,