1 files changed, 46 insertions, 14 deletions

diff --git a/rubocop/cop/graphql/descriptions.rb b/rubocop/cop/graphql/descriptions.rb
index b4e00dfe336..1585e5c9788 100644
--- a/rubocop/cop/graphql/descriptions.rb
+++ b/rubocop/cop/graphql/descriptions.rb
@@ -13,42 +13,74 @@
 #     argument :some_argument, GraphQL::STRING_TYPE
 #   end
 #
+#   class UngoodClass
+#     field :some_argument,
+#       GraphQL::STRING_TYPE,
+#       description: "A description that does not end in a period"
+#   end
+#
 #   # good
 #   class GreatClass
 #     argument :some_field,
 #       GraphQL::STRING_TYPE,
-#       description: "Well described - a superb description"
+#       description: "Well described - a superb description."
 #
 #     field :some_field,
 #       GraphQL::STRING_TYPE,
-#       description: "A thorough and compelling description"
+#       description: "A thorough and compelling description."
 #   end
 
 module RuboCop
   module Cop
     module Graphql
       class Descriptions < RuboCop::Cop::Cop
-        MSG = 'Please add a `description` property.'
+        MSG_NO_DESCRIPTION = 'Please add a `description` property.'
+        MSG_NO_PERIOD = '`description` strings must end with a `.`.'
 
         # 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 $...)
+        def_node_matcher :field_or_argument?, <<~PATTERN
+          (send nil? {:field :argument} ...)
         PATTERN
 
-        def_node_matcher :has_description?, <<~PATTERN
-          (hash <(pair (sym :description) _) ...>)
+        def_node_matcher :description, <<~PATTERN
+          (... (hash <(pair (sym :description) $_) ...>))
         PATTERN
 
         def on_send(node)
-          matches = fields(node) || arguments(node)
+          return unless field_or_argument?(node)
+
+          description = description(node)
+
+          return add_offense(node, location: :expression, message: MSG_NO_DESCRIPTION) unless description
+
+          add_offense(node, location: :expression, message: MSG_NO_PERIOD) if no_period?(description)
+        end
+
+        # Autocorrect missing periods at end of description.
+        def autocorrect(node)
+          lambda do |corrector|
+            description = description(node)
+            next unless description
+
+            corrector.insert_after(before_end_quote(description), '.')
+          end
+        end
+
+        private
+
+        def no_period?(description)
+          # Test that the description node is a `:str` (as opposed to
+          # a `#copy_field_description` call) before checking.
+          description.type == :str && !description.value.strip.end_with?('.')
+        end
 
-          return if matches.nil?
+        # Returns a Parser::Source::Range that ends just before the final String delimiter.
+        def before_end_quote(string)
+          return string.source_range.adjust(end_pos: -1) unless string.heredoc?
 
-          add_offense(node, location: :expression) unless has_description?(matches.last)
+          heredoc_source = string.location.heredoc_body.source
+          adjust = heredoc_source.index(/\s+\Z/) - heredoc_source.length
+          string.location.heredoc_body.adjust(end_pos: adjust)
         end
       end
     end