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:
| Code | Description | Since | Comment |
|---|---|---|---|
DEFAULT_VALUE_USES_INACCESSIBLE | An 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_ERROR | Error when composing custom directives. | 2.1.0 | |
DIRECTIVE_DEFINITION_INVALID | A built-in or federation directive has an invalid definition in the schema. | 2.0.0 | Replaces: TAG_DEFINITION_INVALID |
DISALLOWED_INACCESSIBLE | An element is marked as @inaccessible that is not allowed to be @inaccessible. | 2.0.0 | |
DOWNSTREAM_SERVICE_ERROR | Indicates an error in a subgraph service query during query execution in a federated service. | 0.x | |
EMPTY_MERGED_ENUM_TYPE | An 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_TYPE | An 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_MISMATCH | An 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_BASE | A subgraph is attempting to extend a type that is not originally defined in any known subgraph. | 0.x | |
EXTERNAL_ARGUMENT_DEFAULT_MISMATCH | An @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_MISSING | An @external field is missing some arguments present in the declaration(s) of that field in other subgraphs. | 2.0.0 | |
EXTERNAL_ARGUMENT_TYPE_MISMATCH | An @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_DIRECTIVE | The @external directive collides with other directives in some situations. | 2.1.0 | |
EXTERNAL_MISSING_ON_BASE | A field is marked as @external in a subgraph but with no non-external declaration in any other subgraph. | 0.x | |
EXTERNAL_ON_INTERFACE | The 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 nonsensical | 2.0.0 | |
EXTERNAL_TYPE_MISMATCH | An @external field has a type that is incompatible with the declaration(s) of that field in other subgraphs. | 0.x | |
EXTERNAL_UNUSED | An @external field is not being used by any instance of @key, @requires, @provides or to satisfy an interface implementation. | 0.x | |
FIELD_ARGUMENT_DEFAULT_MISMATCH | An 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_MISMATCH | An argument (of a field/directive) has a type that is incompatible with that of other declarations of that same argument in other subgraphs. | 2.0.0 | Replaces: VALUE_TYPE_INPUT_VALUE_MISMATCH |
FIELD_TYPE_MISMATCH | A field has a type that is incompatible with other declarations of that field in other subgraphs. | 2.0.0 | Replaces: VALUE_TYPE_FIELD_TYPE_MISMATCH |
IMPLEMENTED_BY_INACCESSIBLE | An element is marked as @inaccessible but implements an element visible in the API schema. | 2.0.0 | |
INPUT_FIELD_DEFAULT_MISMATCH | An 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_MISMATCH | For 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_IMPLEM | After 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_SUPERGRAPH | Indicates that a schema provided for an Apollo Federation supergraph is not a valid supergraph schema. | 2.1.0 | |
INVALID_FIELD_SHARING | A field that is non-shareable in at least one subgraph is resolved by multiple subgraphs. | 2.0.0 | |
INVALID_GRAPHQL | A schema is invalid GraphQL: it violates one of the rule of the specification. | 2.0.0 | |
INVALID_LINK_DIRECTIVE_USAGE | An application of the @link directive is invalid/does not respect the specification. | 2.0.0 | |
INVALID_LINK_IDENTIFIER | A url/version for a @link feature is invalid/does not respect the specification. | 2.1.0 | |
INVALID_SUBGRAPH_NAME | A subgraph name is invalid (subgraph names cannot be a single underscore ("_")). | 2.0.0 | |
KEY_DIRECTIVE_IN_FIELDS_ARG | The fields argument of a @key directive includes some directive applications. This is not supported | 2.1.0 | |
KEY_FIELDS_HAS_ARGS | The fields argument of a @key directive includes a field defined with arguments (which is not currently supported). | 2.0.0 | |
KEY_FIELDS_SELECT_INVALID_TYPE | The 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 @key | 0.x | |
KEY_INVALID_FIELDS_TYPE | The value passed to the fields argument of a @key directive is not a string. | 2.0.0 | |
KEY_INVALID_FIELDS | The fields argument of a @key directive is invalid (it has invalid syntax, includes unknown fields, ...). | 2.0.0 | |
KEY_UNSUPPORTED_ON_INTERFACE | A @key directive is used on an interface, which is not (yet) supported. | 2.0.0 | |
LINK_IMPORT_NAME_MISMATCH | The 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_EXTERNAL | In a subgraph, a field is both marked @external and has a merged directive applied to it | 2.0.0 | |
NO_QUERIES | None of the composed subgraphs expose any query. | 2.0.0 | |
ONLY_INACCESSIBLE_CHILDREN | A type visible in the API schema has only @inaccessible children. | 2.0.0 | |
OVERRIDE_COLLISION_WITH_ANOTHER_DIRECTIVE | The @override directive cannot be used on external fields, nor to override fields with either @external, @provides, or @requires. | 2.0.0 | |
OVERRIDE_FROM_SELF_ERROR | Field with @override directive has "from" location that references its own subgraph. | 2.0.0 | |
OVERRIDE_SOURCE_HAS_OVERRIDE | Field which is overridden to another subgraph is also marked @override. | 2.0.0 | |
PROVIDES_DIRECTIVE_IN_FIELDS_ARG | The fields argument of a @provides directive includes some directive applications. This is not supported | 2.1.0 | |
PROVIDES_FIELDS_HAS_ARGS | The fields argument of a @provides directive includes a field defined with arguments (which is not currently supported). | 2.0.0 | |
PROVIDES_FIELDS_MISSING_EXTERNAL | The fields argument of a @provides directive includes a field that is not marked as @external. | 0.x | |
PROVIDES_INVALID_FIELDS_TYPE | The value passed to the fields argument of a @provides directive is not a string. | 2.0.0 | |
PROVIDES_INVALID_FIELDS | The fields argument of a @provides directive is invalid (it has invalid syntax, includes unknown fields, ...). | 2.0.0 | |
PROVIDES_ON_NON_OBJECT_FIELD | A @provides directive is used to mark a field whose base type is not an object type. | 2.0.0 | |
PROVIDES_UNSUPPORTED_ON_INTERFACE | A @provides directive is used on an interface, which is not (yet) supported. | 2.0.0 | |
QUERY_ROOT_TYPE_INACCESSIBLE | An element is marked as @inaccessible but is the query root type, which must be visible in the API schema. | 2.0.0 | |
REFERENCED_INACCESSIBLE | An element is marked as @inaccessible but is referenced by an element visible in the API schema. | 2.0.0 | |
REQUIRED_ARGUMENT_MISSING_IN_SOME_SUBGRAPH | An 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_INACCESSIBLE | An 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_SUBGRAPH | A 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_ARG | The fields argument of a @requires directive includes some directive applications. This is not supported | 2.1.0 | |
REQUIRES_FIELDS_HAS_ARGS | The fields argument of a @requires directive includes a field defined with arguments (which is not currently supported). | 2.0.0 | |
REQUIRES_FIELDS_MISSING_EXTERNAL | The fields argument of a @requires directive includes a field that is not marked as @external. | 0.x | |
REQUIRES_INVALID_FIELDS_TYPE | The value passed to the fields argument of a @requires directive is not a string. | 2.0.0 | |
REQUIRES_INVALID_FIELDS | The fields argument of a @requires directive is invalid (it has invalid syntax, includes unknown fields, ...). | 2.0.0 | |
REQUIRES_UNSUPPORTED_ON_INTERFACE | A @requires directive is used on an interface, which is not (yet) supported. | 2.0.0 | |
ROOT_MUTATION_USED | A 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_USED | A 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_USED | A 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_ERROR | Subgraphs can be merged, but the resulting supergraph API would have queries that cannot be satisfied by those subgraphs. | 2.0.0 | |
TYPE_DEFINITION_INVALID | A built-in or federation type has an invalid definition in the schema. | 2.0.0 | |
TYPE_KIND_MISMATCH | A 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. | 2.0.0 | Replaces: VALUE_TYPE_KIND_MISMATCH, EXTENSION_OF_WRONG_KIND, ENUM_MISMATCH_TYPE |
TYPE_WITH_ONLY_UNUSED_EXTERNAL | A 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 raised | 2.0.0 | |
UNKNOWN_FEDERATION_LINK_VERSION | The version of federation in a @link directive on the schema is unknown. | 2.0.0 | |
UNKNOWN_LINK_VERSION | The version of @link set on the schema is unknown. | 2.1.0 | |
UNSUPPORTED_FEATURE | Indicates an error due to feature currently unsupported by federation. | 2.1.0 | |
UNSUPPORTED_LINKED_FEATURE | Indicates 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 Code | Comment |
|---|---|
DUPLICATE_ENUM_DEFINITION | As duplicate enum definitions is invalid GraphQL, this will now be an error with code INVALID_GRAPHQL |
DUPLICATE_ENUM_VALUE | As duplicate enum values is invalid GraphQL, this will now be an error with code INVALID_GRAPHQL |
DUPLICATE_SCALAR_DEFINITION | As duplicate scalar definitions is invalid GraphQL, this will now be an error with code INVALID_GRAPHQL |
ENUM_MISMATCH | Subgraph definitions for an enum are now merged by composition |
EXTERNAL_USED_ON_BASE | As there is not type ownership anymore, there is also no particular limitation as to where a field can be external. |
KEY_FIELDS_MISSING_EXTERNAL | Using @external for key fields is now discouraged, unless the field is truly meant to be external. |
KEY_FIELDS_MISSING_ON_BASE | Keys can now use any field from any other subgraph. |
KEY_MISSING_ON_BASE | Each subgraph is now free to declare a key only if it needs it. |
KEY_NOT_SPECIFIED | Each subgraph can declare key independently of any other subgraph. |
MULTIPLE_KEYS_ON_EXTENSION | Every subgraph can have multiple keys, as necessary. |
NON_REPEATABLE_DIRECTIVE_ARGUMENTS_MISMATCH | Since 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_MISSING_ON_BASE | Fields in @requires can now be from any subgraph. |
REQUIRES_USED_ON_BASE | As there is not type ownership anymore, there is also no particular limitation as to which subgraph can use a @requires. |
RESERVED_FIELD_USED | This error was previously not correctly enforced: the _service and _entities, if present, were overridden; this is still the case |
VALUE_TYPE_NO_ENTITY | There 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_MISMATCH | Subgraph definitions for an union are now merged by composition |