1 files changed, 56 insertions, 0 deletions
diff --git a/rubocop/cop/graphql/descriptions.rb b/rubocop/cop/graphql/descriptions.rb
new file mode 100644
index 00000000000..b4e00dfe336
--- /dev/null
+++ b/rubocop/cop/graphql/descriptions.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+# This cop checks for missing GraphQL field descriptions.
+#
+# @example
+#
+#   # bad
+#   class AwfulClass
+#     field :some_field, GraphQL::STRING_TYPE
+#   end
+#
+#   class TerribleClass
+#     argument :some_argument, GraphQL::STRING_TYPE
+#   end
+#
+#   # good
+#   class GreatClass
+#     argument :some_field,
+#       GraphQL::STRING_TYPE,
+#       description: "Well described - a superb description"
+#
+#     field :some_field,
+#       GraphQL::STRING_TYPE,
+#       description: "A thorough and compelling description"
+#   end
+
+module RuboCop
+  module Cop
+    module Graphql
+      class Descriptions < RuboCop::Cop::Cop
+        MSG = 'Please add a `description` property.'
+
+        # ability_field and permission_field set a default description.
+        def_node_matcher :fields, <<~PATTERN
+          (send nil? :field $...)
+        PATTERN
+
+        def_node_matcher :arguments, <<~PATTERN
+          (send nil? :argument $...)
+        PATTERN
+
+        def_node_matcher :has_description?, <<~PATTERN
+          (hash <(pair (sym :description) _) ...>)
+        PATTERN
+
+        def on_send(node)
+          matches = fields(node) || arguments(node)
+
+          return if matches.nil?
+
+          add_offense(node, location: :expression) unless has_description?(matches.last)
+        end
+      end
+    end
+  end
+end