1 files changed, 35 insertions, 0 deletions
diff --git a/app/graphql/resolvers/concerns/board_item_filterable.rb b/app/graphql/resolvers/concerns/board_item_filterable.rb
new file mode 100644
index 00000000000..1457a02e44f
--- /dev/null
+++ b/app/graphql/resolvers/concerns/board_item_filterable.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module BoardItemFilterable
+  extend ActiveSupport::Concern
+
+  private
+
+  def item_filters(args)
+    filters = args.to_h
+
+    set_filter_values(filters)
+
+    if filters[:not]
+      set_filter_values(filters[:not])
+    end
+
+    filters
+  end
+
+  def set_filter_values(filters)
+    filter_by_assignee(filters)
+  end
+
+  def filter_by_assignee(filters)
+    if filters[:assignee_username] && filters[:assignee_wildcard_id]
+      raise ::Gitlab::Graphql::Errors::ArgumentError, 'Incompatible arguments: assigneeUsername, assigneeWildcardId.'
+    end
+
+    if filters[:assignee_wildcard_id]
+      filters[:assignee_id] = filters.delete(:assignee_wildcard_id)
+    end
+  end
+end
+
+::BoardItemFilterable.prepend_mod_with('Resolvers::BoardItemFilterable')