fix(GraphQL): Requesting only __typename now returns results

graphql/e2e/common/query.go

@@ -1131,6 +1131,65 @@ func queryTypename(t *testing.T) {
 
 }
 
+func queryOnlyTypename(t *testing.T) {
+	getCountryParams := &GraphQLParams{
+		Query: `query queryCountry {
+			queryCountry {
+				__typename
+			}
+		}`,
+	}
+
+	gqlResponse := getCountryParams.ExecuteAsPost(t, graphqlURL)
+	RequireNoGQLErrors(t, gqlResponse)
+
+	expected := `{
+	"queryCountry": [
+          {
+                "__typename": "Country"
+          },
+          {
+                "__typename": "Country"
+          },
+          {
+                "__typename": "Country"
+          }
+        ]
+}`
+	testutil.CompareJSON(t, expected, string(gqlResponse.Data))
+
+}
+
+func queryNestedOnlyTypename(t *testing.T) {
+	getCountryParams := &GraphQLParams{
+		Query: `query {
+			queryAuthor(filter: { name: { eq: "Ann Author" } }) {
+				posts {
+					__typename
+				}
+			}
+		}`,
+	}
+
+	gqlResponse := getCountryParams.ExecuteAsPost(t, graphqlURL)
+	RequireNoGQLErrors(t, gqlResponse)
+
+	expected := `{
+	"queryAuthor": [
+	  {
+		"posts": [
+		  {
+			"__typename": "Post"
+		  },
+          {
+			"__typename": "Post"
+		  }
+		]
+	  }
+	]
+}`
+	testutil.CompareJSON(t, expected, string(gqlResponse.Data))
+}
 func queryNestedTypename(t *testing.T) {
 	getCountryParams := &GraphQLParams{
 		Query: `query {

graphql/resolve/query.go

@@ -101,6 +101,11 @@ func (qr *queryResolver) rewriteAndExecute(ctx context.Context, query schema.Que
 		return emptyResult(schema.GQLWrapf(err, "Dgraph query failed"))
 	}
 
+	//if string(resp.GetJson()) == fmt.Sprintf(`{"%s":[]}`, query.Name()) {
+	// 	resp.Json = []byte(fmt.Sprintf(`{"%s":[{"dgraph.type":"%s"}]}`, query.Name(),
+	//  	query.Type().Name()))
+	//  }
+
 	resolved := completeDgraphResult(ctx, query, resp.GetJson(), err)
 	resolved.Extensions =
 		&schema.Extensions{TouchedUids: resp.GetMetrics().GetNumUids()[touchedUidsKey]}

graphql/resolve/query_rewriter.go

@@ -172,28 +172,38 @@ func intersection(a, b []uint64) []uint64 {
 // then Dgraph would just return 7 posts.  And we'd have no way of knowing if
 // there's only 7 posts, or if there's more that are missing 'text'.
 // But, for GraphQL, we want to know about those missing values.
-func addUID(dgQuery *gql.GraphQuery) {
-	if len(dgQuery.Children) == 0 {
+func addUID(dgQuery *gql.GraphQuery, addIfNoChild bool) {
+	if len(dgQuery.Children) == 0 && addIfNoChild {
+		addUIDChild(dgQuery)
 		return
 	}
 	hasUid := false
 	for _, c := range dgQuery.Children {
 		if c.Attr == "uid" {
 			hasUid = true
 		}
-		addUID(c)
+		addUID(c, false)
 	}
-
 	// If uid was already requested by the user then we don't need to add it again.
 	if hasUid {
 		return
 	}
+	addUIDChild(dgQuery)
+}
+
+func addUIDChild(dgQuery *gql.GraphQuery) {
 	uidChild := &gql.GraphQuery{
 		Attr:  "uid",
 		Alias: "dgraph.uid",
 	}
 	dgQuery.Children = append(dgQuery.Children, uidChild)
 }
+func (authRw *authRewriter) writingAuth() bool {
+	if authRw == nil || !authRw.isWritingAuth {
+		return false
+	}
+	return true
+}
 
 func rewriteAsQueryByIds(field schema.Field, uids []uint64, authRw *authRewriter) *gql.GraphQuery {
 	rbac := authRw.evaluateStaticRules(field.Type())
@@ -217,7 +227,13 @@ func rewriteAsQueryByIds(field schema.Field, uids []uint64, authRw *authRewriter
 
 	addArgumentsToField(dgQuery, field)
 	selectionAuth := addSelectionSetFrom(dgQuery, field, authRw)
-	addUID(dgQuery)
+
+	if authRw.writingAuth() {
+		addUID(dgQuery, true)
+	} else {
+		addUID(dgQuery, false)
+	}
+
 	addCascadeDirective(dgQuery, field)
 
 	if rbac == schema.Uncertain {
@@ -314,7 +330,11 @@ func rewriteAsGet(
 		}
 	}
 	selectionAuth := addSelectionSetFrom(dgQuery, field, auth)
-	addUID(dgQuery)
+	if auth.writingAuth() {
+		addUID(dgQuery, true)
+	} else {
+		addUID(dgQuery, false)
+	}
 	addTypeFilter(dgQuery, field.Type())
 	addCascadeDirective(dgQuery, field)
 
@@ -362,7 +382,13 @@ func rewriteAsQuery(field schema.Field, authRw *authRewriter) *gql.GraphQuery {
 
 	addArgumentsToField(dgQuery, field)
 	selectionAuth := addSelectionSetFrom(dgQuery, field, authRw)
-	addUID(dgQuery)
+
+	if authRw.writingAuth() {
+		addUID(dgQuery, true)
+	} else {
+		addUID(dgQuery, false)
+	}
+
 	addCascadeDirective(dgQuery, field)
 
 	if rbac == schema.Uncertain {