fix: Add __typename support (#871)

As per GQL spec

core/doc.go

@@ -13,6 +13,11 @@ Package core provides commonly shared interfaces and building blocks.
 */
 package core
 
+import (
+	"github.com/sourcenetwork/defradb/client"
+	parserTypes "github.com/sourcenetwork/defradb/query/graphql/parser/types"
+)
+
 const DocKeyFieldIndex int = 0
 
 type DocFields []any
@@ -71,7 +76,18 @@ type RenderKey struct {
 	Key string
 }
 
+type mappingTypeInfo struct {
+	// The index at which the type name is to be held
+	Index int
+
+	// The name of the host type
+	Name string
+}
+
 type DocumentMapping struct {
+	// The type information for the object, if provided.
+	typeInfo client.Option[mappingTypeInfo]
+
 	// The set of fields that should be rendered.
 	//
 	// Fields not in this collection will not be rendered to the consumer.
@@ -109,6 +125,7 @@ func NewDocumentMapping() *DocumentMapping {
 // CloneWithoutRender deep copies the source mapping skipping over the RenderKeys.
 func (source *DocumentMapping) CloneWithoutRender() *DocumentMapping {
 	result := DocumentMapping{
+		typeInfo:      source.typeInfo,
 		IndexesByName: make(map[string][]int, len(source.IndexesByName)),
 		nextIndex:     source.nextIndex,
 		ChildMappings: make([]*DocumentMapping, len(source.ChildMappings)),
@@ -188,7 +205,11 @@ func (mapping *DocumentMapping) ToMap(doc Doc) map[string]any {
 			innerMapping := mapping.ChildMappings[renderKey.Index]
 			renderValue = innerMapping.ToMap(innerV)
 		default:
-			renderValue = innerV
+			if mapping.typeInfo.HasValue() && renderKey.Index == mapping.typeInfo.Value().Index {
+				renderValue = mapping.typeInfo.Value().Name
+			} else {
+				renderValue = innerV
+			}
 		}
 		mappedDoc[renderKey.Key] = renderValue
 	}
@@ -206,6 +227,15 @@ func (mapping *DocumentMapping) Add(index int, name string) {
 	}
 }
 
+func (mapping *DocumentMapping) SetTypeName(typeName string) {
+	index := mapping.GetNextIndex()
+	mapping.Add(index, parserTypes.TypeNameFieldName)
+	mapping.typeInfo = client.Some(mappingTypeInfo{
+		Index: index,
+		Name:  typeName,
+	})
+}
+
 // SetChildAt sets the given child mapping at the given index.
 //
 // If the index is greater than the ChildMappings length the collection will

query/graphql/mapper/mapper.go

@@ -605,14 +605,22 @@ func getTopLevelInfo(
 			mapping.Add(int(f.ID), f.Name)
 		}
 
+		// Setting the type name must be done after adding the fields, as
+		// the typeName index is dynamic, but the field indexes are not
+		mapping.SetTypeName(collectionName)
+
 		return mapping, &desc, nil
 	}
 
 	if parsed.Name == parserTypes.LinksFieldName {
+		mapping.SetTypeName(parserTypes.LinksFieldName)
+
 		for f := range parserTypes.LinksFields {
 			mapping.Add(mapping.GetNextIndex(), f)
 		}
 	} else {
+		mapping.SetTypeName(parserTypes.CommitTypeName)
+
 		for f := range parserTypes.VersionFields {
 			mapping.Add(mapping.GetNextIndex(), f)
 		}

query/graphql/parser/types/types.go

@@ -56,6 +56,10 @@ type (
 )
 
 const (
+	// GQL special field, returns the host object's type name
+	// https://spec.graphql.org/October2021/#sec-Type-Name-Introspection
+	TypeNameFieldName = "__typename"
+
 	Cid     = "cid"
 	Data    = "data"
 	DocKey  = "dockey"
@@ -79,6 +83,7 @@ const (
 
 	ExplainLabel = "explain"
 
+	CommitTypeName  = "Commit"
 	LinksFieldName  = "links"
 	HeightFieldName = "height"
 	CidFieldName    = "cid"
@@ -109,12 +114,13 @@ var (
 	}
 
 	ReservedFields = map[string]bool{
-		VersionFieldName: true,
-		GroupFieldName:   true,
-		CountFieldName:   true,
-		SumFieldName:     true,
-		AverageFieldName: true,
-		DocKeyFieldName:  true,
+		TypeNameFieldName: true,
+		VersionFieldName:  true,
+		GroupFieldName:    true,
+		CountFieldName:    true,
+		SumFieldName:      true,
+		AverageFieldName:  true,
+		DocKeyFieldName:   true,
 	}
 
 	Aggregates = map[string]struct{}{

query/graphql/schema/types/commits.go

@@ -37,7 +37,7 @@ var (
 	// Any self referential type needs to be initalized
 	// inside the init() func
 	CommitObject = gql.NewObject(gql.ObjectConfig{
-		Name: "Commit",
+		Name: parserTypes.CommitTypeName,
 		Fields: gql.Fields{
 			"height": &gql.Field{
 				Type: gql.Int,

tests/integration/query/all_commits/with_dockey_typename_test.go

@@ -0,0 +1,53 @@
+// Copyright 2022 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package all_commits
+
+import (
+	"testing"
+
+	testUtils "github.com/sourcenetwork/defradb/tests/integration"
+)
+
+func TestQueryAllCommitsWithDockeyWithTypeName(t *testing.T) {
+	test := testUtils.QueryTestCase{
+		Description: "Simple all commits query with dockey and typename",
+		Query: `query {
+					allCommits(dockey: "bae-52b9170d-b77a-5887-b877-cbdbb99b009f") {
+						cid
+						__typename
+					}
+				}`,
+		Docs: map[int][]string{
+			0: {
+				`{
+					"Name": "John",
+					"Age": 21
+				}`,
+			},
+		},
+		Results: []map[string]any{
+			{
+				"cid":        "bafybeidst2mzxhdoh4ayjdjoh4vibo7vwnuoxk3xgyk5mzmep55jklni2a",
+				"__typename": "Commit",
+			},
+			{
+				"cid":        "bafybeihhypcsqt7blkrqtcmpl43eo3yunrog5pchox5naji6hisdme4swm",
+				"__typename": "Commit",
+			},
+			{
+				"cid":        "bafybeid57gpbwi4i6bg7g357vwwyzsmr4bjo22rmhoxrwqvdxlqxcgaqvu",
+				"__typename": "Commit",
+			},
+		},
+	}
+
+	executeTestCase(t, test)
+}

tests/integration/query/one_to_many/with_typename_test.go

@@ -0,0 +1,63 @@
+// Copyright 2022 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package one_to_many
+
+import (
+	"testing"
+
+	testUtils "github.com/sourcenetwork/defradb/tests/integration"
+)
+
+func TestQueryOneToManyWithTypeName(t *testing.T) {
+	test := testUtils.QueryTestCase{
+		Description: "One-to-many relation query from one side with typename",
+		Query: `query {
+					book {
+						name
+						__typename
+						author {
+							name
+							__typename
+						}
+					}
+				}`,
+		Docs: map[int][]string{
+			//books
+			0: { // bae-fd541c25-229e-5280-b44b-e5c2af3e374d
+				`{
+					"name": "Painted House",
+					"rating": 4.9,
+					"author_id": "bae-41598f0c-19bc-5da6-813b-e80f14a10df3"
+				}`,
+			},
+			//authors
+			1: { // bae-41598f0c-19bc-5da6-813b-e80f14a10df3
+				`{
+					"name": "John Grisham",
+					"age": 65,
+					"verified": true
+				}`,
+			},
+		},
+		Results: []map[string]any{
+			{
+				"name":       "Painted House",
+				"__typename": "book",
+				"author": map[string]any{
+					"name":       "John Grisham",
+					"__typename": "author",
+				},
+			},
+		},
+	}
+
+	executeTestCase(t, test)
+}

tests/integration/query/simple/with_group_typename_test.go

@@ -0,0 +1,77 @@
+// Copyright 2022 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package simple
+
+import (
+	"testing"
+
+	testUtils "github.com/sourcenetwork/defradb/tests/integration"
+)
+
+func TestQuerySimpleWithGroupByWithTypeName(t *testing.T) {
+	test := testUtils.QueryTestCase{
+		Description: "Simple query group by and parent typename",
+		Query: `query {
+					users(groupBy: [Name]) {
+						Name
+						__typename
+					}
+				}`,
+		Docs: map[int][]string{
+			0: {
+				`{
+					"Name": "John"
+				}`,
+			},
+		},
+		Results: []map[string]any{
+			{
+				"Name":       "John",
+				"__typename": "users",
+			},
+		},
+	}
+
+	executeTestCase(t, test)
+}
+
+func TestQuerySimpleWithGroupByWithChildTypeName(t *testing.T) {
+	test := testUtils.QueryTestCase{
+		Description: "Simple query group by and child typename",
+		Query: `query {
+					users(groupBy: [Name]) {
+						Name
+						_group {
+							__typename
+						}
+					}
+				}`,
+		Docs: map[int][]string{
+			0: {
+				`{
+					"Name": "John"
+				}`,
+			},
+		},
+		Results: []map[string]any{
+			{
+				"Name": "John",
+				"_group": []map[string]any{
+					{
+						"__typename": "users",
+					},
+				},
+			},
+		},
+	}
+
+	executeTestCase(t, test)
+}