Make Query::Partial able to run a fragment

lib/graphql/execution/interpreter/runtime.rb

@@ -123,14 +123,14 @@ def run_eager
             case inner_type.kind.name
             when "SCALAR", "ENUM"
               result_name = ast_node.alias || ast_node.name
-              owner_type = query.field_definition.owner
+              field_defn = query.field_definition
+              owner_type = field_defn.owner
               selection_result = GraphQLResultHash.new(nil, owner_type, nil, nil, false, EmptyObjects::EMPTY_ARRAY, false, ast_node, nil, nil)
               selection_result.base_path = base_path
               selection_result.ordered_result_keys = [result_name]
               runtime_state = get_current_runtime_state
               runtime_state.current_result = selection_result
               runtime_state.current_result_name = result_name
-              field_defn = query.field_definition
               continue_value = continue_value(object, field_defn, false, ast_node, result_name, selection_result)
               if HALT != continue_value
                 continue_field(continue_value, owner_type, field_defn, root_type, ast_node, nil, false, nil, nil, result_name, selection_result, false, runtime_state) # rubocop:disable Metrics/ParameterLists
@@ -156,14 +156,14 @@ def run_eager
             end
           when "SCALAR", "ENUM"
             result_name = ast_node.alias || ast_node.name
-            owner_type = query.field_definition.owner
-            selection_result = GraphQLResultHash.new(nil, query.parent_type, nil, nil, false, EmptyObjects::EMPTY_ARRAY, false, ast_node, nil, nil)
+            field_defn = query.field_definition
+            owner_type = field_defn.owner
+            selection_result = GraphQLResultHash.new(nil, owner_type, nil, nil, false, EmptyObjects::EMPTY_ARRAY, false, ast_node, nil, nil)
             selection_result.ordered_result_keys = [result_name]
             selection_result.base_path = base_path
             runtime_state = get_current_runtime_state
             runtime_state.current_result = selection_result
             runtime_state.current_result_name = result_name
-            field_defn = query.field_definition
             continue_value = continue_value(object, field_defn, false, ast_node, result_name, selection_result)
             if HALT != continue_value
               continue_field(continue_value, owner_type, field_defn, query.root_type, ast_node, nil, false, nil, nil, result_name, selection_result, false, runtime_state) # rubocop:disable Metrics/ParameterLists

lib/graphql/query/partial.rb

@@ -18,7 +18,8 @@ class Partial
       # @param object [Object] A starting object for execution
       # @param query [GraphQL::Query] A full query instance that this partial is based on. Caches are shared.
       # @param context [Hash] Extra context values to merge into `query.context`, if provided
-      def initialize(path:, object:, query:, context: nil)
+      # @param fragment_node [GraphQL::Language::Nodes::InlineFragment, GraphQL::Language::Nodes::FragmentDefinition]
+      def initialize(path: nil, object:, query:, context: nil, fragment_node: nil, type: nil)
         @path = path
         @object = object
         @query = query
@@ -31,65 +32,26 @@ def initialize(path:, object:, query:, context: nil)
         @multiplex = nil
         @result_values = nil
         @result = nil
-        selections = [@query.selected_operation]
-        type = @query.root_type
-        parent_type = nil
-        field_defn = nil
-        @path.each do |name_in_doc|
-          if name_in_doc.is_a?(Integer)
-            if type.list?
-              type = type.unwrap
-              next
-            else
-              raise ArgumentError, "Received path with index `#{name_in_doc}`, but type wasn't a list. Type: #{type.to_type_signature}, path: #{@path}"
-            end
-          end
-
-          next_selections = []
-          selections.each do |selection|
-            selections_to_check = []
-            selections_to_check.concat(selection.selections)
-            while (sel = selections_to_check.shift)
-              case sel
-              when GraphQL::Language::Nodes::InlineFragment
-                selections_to_check.concat(sel.selections)
-              when GraphQL::Language::Nodes::FragmentSpread
-                fragment = @query.fragments[sel.name]
-                selections_to_check.concat(fragment.selections)
-              when GraphQL::Language::Nodes::Field
-                if sel.alias == name_in_doc || sel.name == name_in_doc
-                  next_selections << sel
-                end
-              else
-                raise "Unexpected selection in partial path: #{sel.class}, #{sel.inspect}"
-              end
-            end
-          end
 
-          if next_selections.empty?
-            raise ArgumentError, "Path `#{@path.inspect}` is not present in this query. `#{name_in_doc.inspect}` was not found. Try a different path or rewrite the query to include it."
-          end
-          field_name = next_selections.first.name
-          field_defn = @schema.get_field(type, field_name, @query.context) || raise("Invariant: no field called #{field_name} on #{type.graphql_name}")
-          parent_type = type
-          type = field_defn.type
-          if type.non_null?
-            type = type.of_type
-          end
-          selections = next_selections
+        if fragment_node
+          @ast_nodes = [fragment_node]
+          @root_type = type || raise(ArgumentError, "Pass `type:` when using `node:`")
+          # This is only used when `@leaf`
+          @field_definition = nil
+        elsif path.nil?
+          raise ArgumentError, "`path:` is required if `node:` is not given; add `path:`"
+        else
+          set_type_info_from_path
         end
-        @parent_type = parent_type
-        @ast_nodes = selections
-        @root_type = type
-        @field_definition = field_defn
+
         @leaf = @root_type.unwrap.kind.leaf?
       end
 
       def leaf?
         @leaf
       end
 
-      attr_reader :context, :query, :ast_nodes, :root_type, :object, :field_definition, :path, :parent_type, :schema
+      attr_reader :context, :query, :ast_nodes, :root_type, :object, :field_definition, :path, :schema
 
       attr_accessor :multiplex, :result_values
 
@@ -155,6 +117,63 @@ def static_errors
       def selected_operation_name
         @query.selected_operation_name
       end
+
+      private
+
+      def set_type_info_from_path
+        selections = [@query.selected_operation]
+        type = @query.root_type
+        parent_type = nil
+        field_defn = nil
+
+        @path.each do |name_in_doc|
+          if name_in_doc.is_a?(Integer)
+            if type.list?
+              type = type.unwrap
+              next
+            else
+              raise ArgumentError, "Received path with index `#{name_in_doc}`, but type wasn't a list. Type: #{type.to_type_signature}, path: #{@path}"
+            end
+          end
+
+          next_selections = []
+          selections.each do |selection|
+            selections_to_check = []
+            selections_to_check.concat(selection.selections)
+            while (sel = selections_to_check.shift)
+              case sel
+              when GraphQL::Language::Nodes::InlineFragment
+                selections_to_check.concat(sel.selections)
+              when GraphQL::Language::Nodes::FragmentSpread
+                fragment = @query.fragments[sel.name]
+                selections_to_check.concat(fragment.selections)
+              when GraphQL::Language::Nodes::Field
+                if sel.alias == name_in_doc || sel.name == name_in_doc
+                  next_selections << sel
+                end
+              else
+                raise "Unexpected selection in partial path: #{sel.class}, #{sel.inspect}"
+              end
+            end
+          end
+
+          if next_selections.empty?
+            raise ArgumentError, "Path `#{@path.inspect}` is not present in this query. `#{name_in_doc.inspect}` was not found. Try a different path or rewrite the query to include it."
+          end
+          field_name = next_selections.first.name
+          field_defn = @schema.get_field(type, field_name, @query.context) || raise("Invariant: no field called #{field_name} on #{type.graphql_name}")
+          parent_type = type
+          type = field_defn.type
+          if type.non_null?
+            type = type.of_type
+          end
+          selections = next_selections
+        end
+
+        @ast_nodes = selections
+        @root_type = type
+        @field_definition = field_defn
+      end
     end
   end
 end

spec/graphql/query/partial_spec.rb

@@ -65,6 +65,14 @@ def neighboring_farm
       end
     end
 
+    class UpcasedFarm < GraphQL::Schema::Object
+      field :name, String
+
+      def name
+        object[:name].upcase
+      end
+    end
+
     class Market < GraphQL::Schema::Object
       implements Entity
       field :is_year_round, Boolean
@@ -174,6 +182,43 @@ def run_partials(string, partial_configs, **query_kwargs)
     ], results
   end
 
+  it "runs inline fragments" do
+    str = "{
+      farm(id: \"1\") {
+        ... on Farm {
+          name
+          ... {
+            n2: name
+          }
+        }
+      }
+    }"
+
+    document = GraphQL.parse(str)
+    fragment_node = document.definitions.first.selections.first.selections.first
+    other_fragment_node = fragment_node.selections[1]
+    results = run_partials(str, [
+      { fragment_node: fragment_node, type: PartialSchema::Farm, object: { name: "Belair Farm" } },
+      { fragment_node: other_fragment_node, type: PartialSchema::UpcasedFarm, object: { name: "Free Union Grass Farm" } }
+    ])
+    assert_equal({ "name" => "Belair Farm", "n2" => "Belair Farm" }, results[0]["data"])
+    assert_equal({ "n2" => "FREE UNION GRASS FARM" }, results[1]["data"])
+  end
+
+  it "runs fragment definitions" do
+    str = "{
+     farm(id: \"1\") { ... farmFields }
+    }
+
+    fragment farmFields on Farm {
+      farmName: name
+    }"
+
+    node = GraphQL.parse(str).definitions.last
+    results = run_partials(str, [{ fragment_node: node, type: PartialSchema::Farm, object: { name: "Clovertop Creamery" } }])
+    assert_equal({ "farmName" => "Clovertop Creamery" }, results[0]["data"])
+  end
+
   it "works with GraphQL::Current" do
     res = run_partials("query CheckCurrentValues { query { currentValues } }", [path: ["query"], object: nil])
     assert_equal ["CheckCurrentValues", "Query.currentValues", "nil"], res[0]["data"]["currentValues"]