1 files changed, 39 insertions, 0 deletions
diff --git a/lib/gitlab/graphql/batch_key.rb b/lib/gitlab/graphql/batch_key.rb
new file mode 100644
index 00000000000..51203af5a43
--- /dev/null
+++ b/lib/gitlab/graphql/batch_key.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Graphql
+    class BatchKey
+      attr_reader :object
+      delegate :hash, to: :object
+
+      def initialize(object, lookahead = nil, object_name: nil)
+        @object = object
+        @lookahead = lookahead
+        @object_name = object_name
+      end
+
+      def requires?(path)
+        return false unless @lookahead
+        return false unless path.present?
+
+        field = path.pop
+
+        path
+          .reduce(@lookahead) { |q, f| q.selection(f) }
+          .selects?(field)
+      end
+
+      def eql?(other)
+        other.is_a?(self.class) && object == other.object
+      end
+      alias_method :==, :eql?
+
+      def method_missing(method_name, *args, **kwargs)
+        return @object if method_name.to_sym == @object_name
+        return @object.public_send(method_name) if args.empty? && kwargs.empty? # rubocop: disable GitlabSecurity/PublicSend
+
+        super
+      end
+    end
+  end
+end