Fix branch_or_tag parse constraint, minor refactor. Refs #263

lib/ext/rosa/constraints.rb

@@ -24,7 +24,7 @@ module Rosa
         if (params = request.path_parameters) && params[:treeish] # parse existing branch (tag) and path
           branch_or_tag = begin
             (p = Project.find_by_owner_and_name params[:owner_name], params[:project_name]) &&
-            p.repo.branches_and_tags.detect{|t| params[:treeish].start_with?(t.name)}.try(:name) ||
+            p.repo.branches_and_tags.map(&:name).sort{|a,b| b.length <=> a.length}.detect{|b| params[:treeish].start_with?(b)} ||
             params[:treeish].split('/').first
           end
           if path = params[:treeish].sub(branch_or_tag, '')[1..-1] and path.present?