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Federation error codes


When Apollo Gateway attempts to compose the schemas provided by your subgraphs into a supergraph schema, it confirms that:

  • The subgraphs are valid
  • The resulting supergraph schema is valid
  • The gateway has all of the information it needs to execute operations against the resulting schema

If Apollo Gateway encounters an error, composition fails. This document lists subgraph validation and composition error codes, along with their root causes.

Errors

The following errors might be raised during composition:

CodeDescriptionSinceComment
DEFAULT_VALUE_USES_INACCESSIBLEAn element is marked as @inaccessible but is used in the default value of an element visible in the API schema.2.0.0
DIRECTIVE_COMPOSITION_ERRORError when composing custom directives.2.1.0
DIRECTIVE_DEFINITION_INVALIDA built-in or federation directive has an invalid definition in the schema.2.0.0Replaces: TAG_DEFINITION_INVALID
DISALLOWED_INACCESSIBLEAn element is marked as @inaccessible that is not allowed to be @inaccessible.2.0.0
DOWNSTREAM_SERVICE_ERRORIndicates an error in a subgraph service query during query execution in a federated service.0.x
EMPTY_MERGED_ENUM_TYPEAn enum type has no value common to all the subgraphs that define the type. Merging that type would result in an invalid empty enum type.2.0.0
EMPTY_MERGED_INPUT_TYPEAn input object type has no field common to all the subgraphs that define the type. Merging that type would result in an invalid empty input object type.2.0.0
ENUM_VALUE_MISMATCHAn enum type that is used as both an input and output type has a value that is not defined in all the subgraphs that define the enum type.2.0.0
EXTENSION_WITH_NO_BASEA subgraph is attempting to extend a type that is not originally defined in any known subgraph.0.x
EXTERNAL_ARGUMENT_DEFAULT_MISMATCHAn @external field declares an argument with a default that is incompatible with the corresponding argument in the declaration(s) of that field in other subgraphs.2.0.0
EXTERNAL_ARGUMENT_MISSINGAn @external field is missing some arguments present in the declaration(s) of that field in other subgraphs.2.0.0
EXTERNAL_ARGUMENT_TYPE_MISMATCHAn @external field declares an argument with a type that is incompatible with the corresponding argument in the declaration(s) of that field in other subgraphs.2.0.0
EXTERNAL_COLLISION_WITH_ANOTHER_DIRECTIVEThe @external directive collides with other directives in some situations.2.1.0
EXTERNAL_MISSING_ON_BASEA field is marked as @external in a subgraph but with no non-external declaration in any other subgraph.0.x
EXTERNAL_ON_INTERFACEThe field of an interface type is marked with @external: as external is about marking field not resolved by the subgraph and as interface field are not resolved (only implementations of those fields are), an "external" interface field is nonsensical2.0.0
EXTERNAL_TYPE_MISMATCHAn @external field has a type that is incompatible with the declaration(s) of that field in other subgraphs.0.x
EXTERNAL_UNUSEDAn @external field is not being used by any instance of @key, @requires, @provides or to satisfy an interface implementation.0.x
FIELD_ARGUMENT_DEFAULT_MISMATCHAn argument (of a field/directive) has a default value that is incompatible with that of other declarations of that same argument in other subgraphs.2.0.0
FIELD_ARGUMENT_TYPE_MISMATCHAn argument (of a field/directive) has a type that is incompatible with that of other declarations of that same argument in other subgraphs.2.0.0Replaces: VALUE_TYPE_INPUT_VALUE_MISMATCH
FIELD_TYPE_MISMATCHA field has a type that is incompatible with other declarations of that field in other subgraphs.2.0.0Replaces: VALUE_TYPE_FIELD_TYPE_MISMATCH
IMPLEMENTED_BY_INACCESSIBLEAn element is marked as @inaccessible but implements an element visible in the API schema.2.0.0
INPUT_FIELD_DEFAULT_MISMATCHAn input field has a default value that is incompatible with other declarations of that field in other subgraphs.2.0.0
INTERFACE_FIELD_IMPLEM_TYPE_MISMATCHFor an interface field, some of its concrete implementations have @external or @requires and there is difference in those implementations return type (which is currently not supported; see https://github.com/apollographql/federation/issues/1257)2.0.0
INTERFACE_FIELD_NO_IMPLEMAfter subgraph merging, an implementation is missing a field of one of the interface it implements (which can happen for valid subgraphs).2.0.0
INVALID_FEDERATION_SUPERGRAPHIndicates that a schema provided for an Apollo Federation supergraph is not a valid supergraph schema.2.1.0
INVALID_FIELD_SHARINGA field that is non-shareable in at least one subgraph is resolved by multiple subgraphs.2.0.0
INVALID_GRAPHQLA schema is invalid GraphQL: it violates one of the rule of the specification.2.0.0
INVALID_LINK_DIRECTIVE_USAGEAn application of the @link directive is invalid/does not respect the specification.2.0.0
INVALID_LINK_IDENTIFIERA url/version for a @link feature is invalid/does not respect the specification.2.1.0
INVALID_SHAREABLE_USAGEThe @shareable federation directive is used in an invalid way.2.1.2
INVALID_SUBGRAPH_NAMEA subgraph name is invalid (subgraph names cannot be a single underscore ("_")).2.0.0
KEY_DIRECTIVE_IN_FIELDS_ARGThe fields argument of a @key directive includes some directive applications. This is not supported2.1.0
KEY_FIELDS_HAS_ARGSThe fields argument of a @key directive includes a field defined with arguments (which is not currently supported).2.0.0
KEY_FIELDS_SELECT_INVALID_TYPEThe fields argument of @key directive includes a field whose type is a list, interface, or union type. Fields of these types cannot be part of a @key0.x
KEY_INVALID_FIELDS_TYPEThe value passed to the fields argument of a @key directive is not a string.2.0.0
KEY_INVALID_FIELDSThe fields argument of a @key directive is invalid (it has invalid syntax, includes unknown fields, ...).2.0.0
KEY_UNSUPPORTED_ON_INTERFACEA @key directive is used on an interface, which is not (yet) supported.2.0.0
LINK_IMPORT_NAME_MISMATCHThe import name for a merged directive (as declared by the relevant @link(import:) argument) is inconsistent between subgraphs.2.0.0
MERGED_DIRECTIVE_APPLICATION_ON_EXTERNALIn a subgraph, a field is both marked @external and has a merged directive applied to it2.0.0
NO_QUERIESNone of the composed subgraphs expose any query.2.0.0
ONLY_INACCESSIBLE_CHILDRENA type visible in the API schema has only @inaccessible children.2.0.0
OVERRIDE_COLLISION_WITH_ANOTHER_DIRECTIVEThe @override directive cannot be used on external fields, nor to override fields with either @external, @provides, or @requires.2.0.0
OVERRIDE_FROM_SELF_ERRORField with @override directive has "from" location that references its own subgraph.2.0.0
OVERRIDE_SOURCE_HAS_OVERRIDEField which is overridden to another subgraph is also marked @override.2.0.0
PROVIDES_DIRECTIVE_IN_FIELDS_ARGThe fields argument of a @provides directive includes some directive applications. This is not supported2.1.0
PROVIDES_FIELDS_HAS_ARGSThe fields argument of a @provides directive includes a field defined with arguments (which is not currently supported).2.0.0
PROVIDES_FIELDS_MISSING_EXTERNALThe fields argument of a @provides directive includes a field that is not marked as @external.0.x
PROVIDES_INVALID_FIELDS_TYPEThe value passed to the fields argument of a @provides directive is not a string.2.0.0
PROVIDES_INVALID_FIELDSThe fields argument of a @provides directive is invalid (it has invalid syntax, includes unknown fields, ...).2.0.0
PROVIDES_ON_NON_OBJECT_FIELDA @provides directive is used to mark a field whose base type is not an object type.2.0.0
PROVIDES_UNSUPPORTED_ON_INTERFACEA @provides directive is used on an interface, which is not (yet) supported.2.0.0
QUERY_ROOT_TYPE_INACCESSIBLEAn element is marked as @inaccessible but is the query root type, which must be visible in the API schema.2.0.0
REFERENCED_INACCESSIBLEAn element is marked as @inaccessible but is referenced by an element visible in the API schema.2.0.0
REQUIRED_ARGUMENT_MISSING_IN_SOME_SUBGRAPHAn argument of a field or directive definition is mandatory in some subgraphs, but the argument is not defined in all the subgraphs that define the field or directive definition.2.0.0
REQUIRED_INACCESSIBLEAn element is marked as @inaccessible but is required by an element visible in the API schema.2.0.0
REQUIRED_INPUT_FIELD_MISSING_IN_SOME_SUBGRAPHA field of an input object type is mandatory in some subgraphs, but the field is not defined in all the subgraphs that define the input object type.2.0.0
REQUIRES_DIRECTIVE_IN_FIELDS_ARGThe fields argument of a @requires directive includes some directive applications. This is not supported2.1.0
REQUIRES_FIELDS_MISSING_EXTERNALThe fields argument of a @requires directive includes a field that is not marked as @external.0.x
REQUIRES_INVALID_FIELDS_TYPEThe value passed to the fields argument of a @requires directive is not a string.2.0.0
REQUIRES_INVALID_FIELDSThe fields argument of a @requires directive is invalid (it has invalid syntax, includes unknown fields, ...).2.0.0
REQUIRES_UNSUPPORTED_ON_INTERFACEA @requires directive is used on an interface, which is not (yet) supported.2.0.0
ROOT_MUTATION_USEDA subgraph's schema defines a type with the name mutation, while also specifying a different type name as the root query object. This is not allowed.0.x
ROOT_QUERY_USEDA subgraph's schema defines a type with the name query, while also specifying a different type name as the root query object. This is not allowed.0.x
ROOT_SUBSCRIPTION_USEDA subgraph's schema defines a type with the name subscription, while also specifying a different type name as the root query object. This is not allowed.0.x
SATISFIABILITY_ERRORSubgraphs can be merged, but the resulting supergraph API would have queries that cannot be satisfied by those subgraphs.2.0.0
TYPE_DEFINITION_INVALIDA built-in or federation type has an invalid definition in the schema.2.0.0
TYPE_KIND_MISMATCHA type has the same name in different subgraphs, but a different kind. For instance, one definition is an object type but another is an interface.2.0.0Replaces: VALUE_TYPE_KIND_MISMATCH, EXTENSION_OF_WRONG_KIND, ENUM_MISMATCH_TYPE
TYPE_WITH_ONLY_UNUSED_EXTERNALA federation 1 schema has a composite type comprised only of unused external fields. Note that this error can only be raised for federation 1 schema as federation 2 schema do not allow unused external fields (and errors with code EXTERNAL_UNUSED will be raised in that case). But when federation 1 schema are automatically migrated to federation 2 ones, unused external fields are automatically removed, and in rare case this can leave a type empty. If that happens, an error with this code will be raised2.0.0
UNKNOWN_FEDERATION_LINK_VERSIONThe version of federation in a @link directive on the schema is unknown.2.0.0
UNKNOWN_LINK_VERSIONThe version of @link set on the schema is unknown.2.1.0
UNSUPPORTED_FEATUREIndicates an error due to feature currently unsupported by federation.2.1.0
UNSUPPORTED_LINKED_FEATUREIndicates that a feature used in a @link is either unsupported or is used with unsupported options.2.0.0

Removed codes

The following error codes have been removed and are no longer generated by the most recent version of the @apollo/gateway library:

Removed CodeComment
DUPLICATE_ENUM_DEFINITIONAs duplicate enum definitions is invalid GraphQL, this will now be an error with code INVALID_GRAPHQL
DUPLICATE_ENUM_VALUEAs duplicate enum values is invalid GraphQL, this will now be an error with code INVALID_GRAPHQL
DUPLICATE_SCALAR_DEFINITIONAs duplicate scalar definitions is invalid GraphQL, this will now be an error with code INVALID_GRAPHQL
ENUM_MISMATCHSubgraph definitions for an enum are now merged by composition
EXTERNAL_USED_ON_BASEAs there is not type ownership anymore, there is also no particular limitation as to where a field can be external.
KEY_FIELDS_MISSING_EXTERNALUsing @external for key fields is now discouraged, unless the field is truly meant to be external.
KEY_FIELDS_MISSING_ON_BASEKeys can now use any field from any other subgraph.
KEY_MISSING_ON_BASEEach subgraph is now free to declare a key only if it needs it.
KEY_NOT_SPECIFIEDEach subgraph can declare key independently of any other subgraph.
MULTIPLE_KEYS_ON_EXTENSIONEvery subgraph can have multiple keys, as necessary.
NON_REPEATABLE_DIRECTIVE_ARGUMENTS_MISMATCHSince federation 2.1.0, the case this error used to cover is now a warning (with code INCONSISTENT_NON_REPEATABLE_DIRECTIVE_ARGUMENTS) instead of an error
PROVIDES_FIELDS_SELECT_INVALID_TYPE@provides can now be used on field of interface, union and list types
PROVIDES_NOT_ON_ENTITY@provides can now be used on any type.
REQUIRES_FIELDS_HAS_ARGSSince federation 2.1.1, using fields with arguments in a @requires is fully supported
REQUIRES_FIELDS_MISSING_ON_BASEFields in @requires can now be from any subgraph.
REQUIRES_USED_ON_BASEAs there is not type ownership anymore, there is also no particular limitation as to which subgraph can use a @requires.
RESERVED_FIELD_USEDThis error was previously not correctly enforced: the _service and _entities, if present, were overridden; this is still the case
VALUE_TYPE_NO_ENTITYThere is no strong different between entity and value types in the model (they are just usage pattern) and a type can have keys in one subgraph but not another.
VALUE_TYPE_UNION_TYPES_MISMATCHSubgraph definitions for an union are now merged by composition
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