rework handling of internal typename placeholder

Author: devsergiy

execution/engine/execution_engine_test.go

@@ -1606,7 +1606,7 @@ func TestExecutionEngine_Execute(t *testing.T) {
 						expectedHost:     "example.com",
 						expectedPath:     "/",
 						expectedBody:     "",
-						sendResponseBody: `{"data":{"__internal__typename_placeholder":"Query"}}`,
+						sendResponseBody: `doesn't matter, no fetch will be done, as query typename resolved by engine`,
 						sendStatusCode:   200,
 					}),
 				),
@@ -1644,6 +1644,82 @@ func TestExecutionEngine_Execute(t *testing.T) {
 		expectedResponse: `{"data":{}}`,
 	}))
 
+	t.Run("execute operation with all nested fields skipped", runWithoutError(ExecutionEngineTestCase{
+		schema: func(t *testing.T) *graphql.Schema {
+			t.Helper()
+			schema := `
+			type Query {
+				hero(name: String!): Hero!
+			}
+
+			type Hero {
+				name: String!
+			}
+			`
+			parseSchema, err := graphql.NewSchemaFromString(schema)
+			require.NoError(t, err)
+			return parseSchema
+		}(t),
+		operation: func(t *testing.T) graphql.Request {
+			return graphql.Request{
+				OperationName: "MyHero",
+				Variables:     []byte(`{"heroName": "Luke"}`),
+				Query: `query MyHero($heroName: String!){
+						hero(name: $heroName) {
+							name @skip(if: true)
+						}
+					}`,
+			}
+		},
+		dataSources: []plan.DataSource{
+			mustGraphqlDataSourceConfiguration(t,
+				"id",
+				mustFactory(t,
+					testNetHttpClient(t, roundTripperTestCase{
+						expectedHost:     "example.com",
+						expectedPath:     "/",
+						expectedBody:     "",
+						sendResponseBody: `{"data":{"hero":{"__typename":"Hero"}}}`,
+						sendStatusCode:   200,
+					}),
+				),
+				&plan.DataSourceMetadata{
+					RootNodes: []plan.TypeField{
+						{TypeName: "Query", FieldNames: []string{"hero"}},
+					},
+					ChildNodes: []plan.TypeField{
+						{TypeName: "Hero", FieldNames: []string{"name"}},
+					},
+				},
+				mustConfiguration(t, graphql_datasource.ConfigurationInput{
+					Fetch: &graphql_datasource.FetchConfiguration{
+						URL:    "https://example.com/",
+						Method: "POST",
+					},
+					SchemaConfiguration: mustSchemaConfig(
+						t,
+						nil,
+						`type Query { hero(name: String!): Hero! } type Hero { name: String! }`,
+					),
+				}),
+			),
+		},
+		fields: []plan.FieldConfiguration{
+			{
+				TypeName:  "Query",
+				FieldName: "hero",
+				Path:      []string{"hero"},
+				Arguments: []plan.ArgumentConfiguration{
+					{
+						Name:       "name",
+						SourceType: plan.FieldArgumentSource,
+					},
+				},
+			},
+		},
+		expectedResponse: `{"data":{"hero":{}}}`,
+	}))
+
 	t.Run("execute operation and apply input coercion for lists without variables", runWithoutError(ExecutionEngineTestCase{
 		schema: graphql.InputCoercionForListSchema(t),
 		operation: func(t *testing.T) graphql.Request {

v2/pkg/engine/plan/node_selection_visitor.go

@@ -1,6 +1,7 @@
 package plan
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"slices"
@@ -54,10 +55,13 @@ type nodeSelectionVisitor struct {
 	newFieldRefs map[int]struct{} // newFieldRefs is a set of field refs which were added by the visitor or was modified by a rewrite
 }
 
+func (c *nodeSelectionVisitor) addNewSkipFieldRefs(fieldRefs ...int) {
+	c.addSkipFieldRefs(fieldRefs...)
+	c.addNewFieldRefs(fieldRefs...)
+}
+
 func (c *nodeSelectionVisitor) addSkipFieldRefs(fieldRefs ...int) {
 	c.skipFieldsRefs = append(c.skipFieldsRefs, fieldRefs...)
-
-	c.addNewFieldRefs(fieldRefs...)
 }
 
 func (c *nodeSelectionVisitor) addNewFieldRefs(fieldRefs ...int) {
@@ -255,6 +259,11 @@ func (c *nodeSelectionVisitor) handleEnterField(fieldRef int, handleRequires boo
 }
 
 func (c *nodeSelectionVisitor) LeaveField(ref int) {
+	if bytes.Equal(c.operation.FieldAliasOrNameBytes(ref), []byte("__internal__typename_placeholder")) {
+		// we should skip such typename as it was added as a placeholder to keep query valid
+		// when normalizaion removed all other selections from the selection set
+		c.addSkipFieldRefs(ref)
+	}
 }
 
 func (c *nodeSelectionVisitor) handleFieldRequiredByRequires(fieldRef int, parentPath, typeName, fieldName, currentPath string, dsConfig DataSource) {
@@ -520,7 +529,7 @@ func (c *nodeSelectionVisitor) addFieldRequirementsToOperation(selectionSetRef i
 	}
 	c.resetVisitedAbstractChecksForModifiedFields(addFieldsResult.modifiedFieldRefs)
 
-	c.addSkipFieldRefs(addFieldsResult.skipFieldRefs...)
+	c.addNewSkipFieldRefs(addFieldsResult.skipFieldRefs...)
 	// add mapping for the field dependencies
 	for _, requestedByFieldRef := range requirements.requestedByFieldRefs {
 		fieldKey := fieldIndexKey{requestedByFieldRef, requirements.dsHash}
@@ -610,7 +619,7 @@ func (c *nodeSelectionVisitor) addKeyRequirementsToOperation(selectionSetRef int
 		// op, _ := astprinter.PrintStringIndentDebug(c.operation, " ")
 		// fmt.Println("operation: ", op)
 
-		c.addSkipFieldRefs(addFieldsResult.skipFieldRefs...)
+		c.addNewSkipFieldRefs(addFieldsResult.skipFieldRefs...)
 
 		// setup deps between key chain items
 		if currentFieldRefs != nil && previousJump != nil {
@@ -710,7 +719,7 @@ func (c *nodeSelectionVisitor) rewriteSelectionSetHavingAbstractFragments(fieldR
 		return
 	}
 
-	c.addSkipFieldRefs(rewriter.skipFieldRefs...)
+	c.addNewSkipFieldRefs(rewriter.skipFieldRefs...)
 	c.hasNewFields = true
 	c.rewrittenFieldRefs = append(c.rewrittenFieldRefs, fieldRef)
 	c.persistedRewrittenFieldRefs[fieldRef] = struct{}{}

v2/pkg/engine/plan/visitor.go

@@ -300,11 +300,6 @@ func (v *Visitor) EnterField(ref int) {
 	fieldName := v.Operation.FieldNameBytes(ref)
 	fieldAliasOrName := v.Operation.FieldAliasOrNameBytes(ref)
 
-	if bytes.Equal(fieldAliasOrName, []byte("__internal__typename_placeholder")) {
-		// we should skip such typename as it was added as a placeholder to keep query valid
-		return
-	}
-
 	fieldDefinition, ok := v.Walker.FieldDefinition(ref)
 	if !ok {
 		return