feature: Support inline fragments without a type condition

lib/graphql/language/parser.rb

@@ -26,10 +26,11 @@ class Parser < Parslet::Parser
         directives.maybe.as(:optional_directives).as(:directives)
       }
       rule(:spread) { str("...") }
+      rule(:type_condition) { str("on ") >> name.as(:optional_string_content) }
       # TODO: `on` bug, see spec
       rule(:inline_fragment) {
         spread.as(:fragment_spread_keyword) >> space? >>
-        str("on ") >> name.as(:inline_fragment_type) >> space? >>
+        type_condition.maybe.as(:inline_fragment_type) >> space? >>
         directives.maybe.as(:optional_directives).as(:directives) >> space? >>
         selections.as(:selections)
       }

lib/graphql/language/transform.rb

@@ -40,7 +40,7 @@ def self.optional_sequence(name)
         inline_fragment_type: simple(:n),
         directives: sequence(:d),
         selections: sequence(:s),
-      ) { CREATE_NODE[:InlineFragment, type: n.to_s, directives: d, selections: s, position_source: kw]}
+      ) { CREATE_NODE[:InlineFragment, type: n, directives: d, selections: s, position_source: kw]}
 
       # Operation Definition
       rule(

lib/graphql/query/serial_execution/selection_resolution.rb

@@ -64,6 +64,7 @@ def flatten_fragment(ast_fragment)
         end
 
         def fragment_type_can_apply?(ast_fragment)
+          return true unless ast_fragment.type
           child_type = execution_context.get_type(ast_fragment.type)
           resolved_type = GraphQL::Query::TypeResolver.new(target, child_type, type).type
           !resolved_type.nil?

lib/graphql/static_validation/rules/fragment_spreads_are_possible.rb

@@ -5,8 +5,9 @@ def validate(context)
 
     context.visitor[GraphQL::Language::Nodes::InlineFragment] << -> (node, parent) {
       fragment_parent = context.object_types[-2]
-      fragment_child = context.object_types.last
-      validate_fragment_in_scope(fragment_parent, fragment_child, node, context)
+      if fragment_child = context.object_types.last
+        validate_fragment_in_scope(fragment_parent, fragment_child, node, context)
+      end
     }
 
     spreads_to_validate = []

lib/graphql/static_validation/rules/fragment_types_exist.rb

@@ -15,6 +15,7 @@ def validate(context)
   private
 
   def validate_type_exists(node, context)
+    return unless node.type
     type = context.schema.types.fetch(node.type, nil)
     if type.nil?
       context.errors << message("No such type #{node.type}, so it can't be a fragment condition", node)

lib/graphql/static_validation/rules/fragments_are_on_composite_types.rb

@@ -18,6 +18,7 @@ def validate(context)
 
   def validate_type_is_composite(node, context)
     type_name = node.type
+    return unless type_name
     type_def = context.schema.types[type_name]
     if type_def.nil? || !type_def.kind.composite?
       context.errors <<  message("Invalid fragment on type #{type_name} (must be Union, Interface or Object)", node)

lib/graphql/static_validation/type_stack.rb

@@ -52,7 +52,11 @@ def self.get_strategy_for_node_class(node_class)
 
   class FragmentWithTypeStrategy
     def push(stack, node)
-      object_type = stack.schema.types.fetch(node.type, nil)
+      object_type = if node.type
+        stack.schema.types.fetch(node.type, nil)
+      else
+        stack.object_types.last
+      end
       if !object_type.nil?
         object_type = object_type.unwrap
       end

spec/graphql/directive_spec.rb

@@ -50,6 +50,8 @@
         ... on Cheese @skip(if: false) { dontSkipInlineId: id }
         ... on Cheese @include(if: true) { includeInlineId: id }
         ... on Cheese @include(if: false) { dontIncludeInlineId: id }
+        ... @skip(if: true) { skipNoType: id }
+        ... @skip(if: false) { dontSkipNoType: id }
         }
       }
       fragment includeFlavorField on Cheese { includeFlavor: flavor  }
@@ -66,6 +68,7 @@
           "includeFlavor" => "Brie",
           "dontSkipInlineId" => 1,
           "includeInlineId" => 1,
+          "dontSkipNoType" => 1,
         },
       }}
       assert_equal(expected, result)

spec/graphql/language/parser_spec.rb

@@ -22,6 +22,7 @@
         name,
         ... on Species { color },
         ... family # background info, of course
+        ... @skip(if: true) { inlineFragSkip },
       }
     }
     subscription watchStuff {

spec/graphql/language/transform_spec.rb

@@ -153,4 +153,9 @@ def get_result(query_string, parse: nil, debug: false)
     res = get_result("{quoted: \"\\\" \\\\ \\/ \\b \\f \\n \\r \\t\"}", parse: :value_input_object)
     assert_equal("\" \\ / \b \f \n \r \t", res.arguments[0].value)
   end
+
+  it 'transforms inline fragment optional type condition' do
+    res = get_result("{ ... @skip(if: true) { skippedField }, ... on Pet { isHousebroken } }")
+    assert_equal([nil, "Pet"], res.definitions.first.selections.map(&:type))
+  end
 end