{"record":{"id":"51cc8790df0e1f0d","repo":"dgraph-io/dgraph","slug":"while-validating-graphql-schema","errorCode":null,"errorMessage":"while validating GraphQL schema","messagePattern":"while validating GraphQL schema","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"critical","filePath":"graphql/schema/schemagen.go","lineNumber":54,"sourceCode":"\toriginalDefs   []string\n\tcompleteSchema *ast.Schema\n\tdgraphSchema   string\n\tschemaMeta     *metaInfo\n}\n\n// FromString builds a GraphQL Schema from input string, or returns any parsing\n// or validation errors.\nfunc FromString(schema string, ns uint64) (Schema, error) {\n\t// validator.Prelude includes a bunch of predefined types which help with schema introspection\n\t// queries, hence we include it as part of the schema.\n\tdoc, gqlErr := parser.ParseSchemas(validator.Prelude, &ast.Source{Input: schema})\n\tif gqlErr != nil {\n\t\treturn nil, errors.Wrap(gqlErr, \"while parsing GraphQL schema\")\n\t}\n\n\tgqlSchema, gqlErr := validator.ValidateSchemaDocument(doc)\n\tif gqlErr != nil {\n\t\treturn nil, errors.Wrap(gqlErr, \"while validating GraphQL schema\")\n\t}\n\n\treturn AsSchema(gqlSchema, ns)\n}\n\nfunc (s *handler) MetaInfo() *metaInfo {\n\treturn s.schemaMeta\n}\n\nfunc (s *handler) GQLSchema() string {\n\treturn Stringify(s.completeSchema, s.originalDefs, false)\n}\n\nfunc (s *handler) DGSchema() string {\n\treturn s.dgraphSchema\n}\n\n// GQLSchemaWithoutApolloExtras return GraphQL schema string","sourceCodeStart":36,"sourceCodeEnd":72,"githubUrl":"https://github.com/dgraph-io/dgraph/blob/759e242be62c91f8d084da06ad0c8d21256d9c07/graphql/schema/schemagen.go#L36-L72","documentation":"After successfully parsing the schema document, FromString runs graphql-go's validator.ValidateSchemaDocument. Semantic errors (duplicate type/field names, unknown types referenced, invalid directive usage, missing query root) are wrapped with \"while validating GraphQL schema\".","triggerScenarios":"Calling schema.FromString (or SchemaValidate/NewServers/resetSchema/Resolve) with SDL that parses but violates GraphQL schema rules: duplicate definitions, fields referencing undefined types, invalid @directive arguments, no Query root type.","commonSituations":"Two schema fragments both defining the same type; renamed a type but not its references; merged schemas producing duplicate Query fields; using Dgraph directives with wrong arguments.","solutions":["Read the wrapped validation message (it names the offending type/field) and fix the SDL.","Search the schema for duplicate type/field definitions and remove or merge them.","Ensure every type referenced by a field exists and a Query root type is defined.","Validate locally with SchemaValidate before deploying the schema."],"exampleFix":"// before\ntype Author { posts: [Post] } // Post undefined\ntype Post { title: String }\ntype Post { id: ID } // duplicate\n// after\ntype Author { posts: [Post] }\ntype Post { id: ID, title: String }","handlingStrategy":"try-catch","validationCode":"// pre-check: every referenced type must be defined and Query root present\nfor _, ref := range extractTypeRefs(schemaText) {\n    if !strings.Contains(schemaText, \"type \"+ref) {\n        return fmt.Errorf(\"type %s referenced but not defined\", ref)\n    }\n}\nif !strings.Contains(schemaText, \"type Query\") {\n    return errors.New(\"schema must define a Query root type\")\n}","typeGuard":null,"tryCatchPattern":"sch, err := schema.FromString(schemaText, ns)\nif err != nil {\n    if strings.Contains(err.Error(), \"while validating GraphQL schema\") {\n        return fmt.Errorf(\"semantic schema error: %w\", err)\n    }\n    return err\n}","preventionTips":["Validate merged schema output in CI before applying.","Deduplicate shared type definitions when merging schema fragments.","Rename types via tooling (find-all-references), not manual edits.","Keep Dgraph directive usage documented and linted."],"tags":["graphql","schema","validation"],"backgroundTag":"schema-validation-failed","analyzedSha":"759e242be62c91f8d084da06ad0c8d21256d9c07","analyzedAt":"2026-09-01T14:42:12.034Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}