Migration to v7

Upgrading from v6

If you are using GraphQL Tools v6, there are several breaking changes to be aware of.

Schema Generation and Decoration API (@graphql-tools/schema)

• Resolver validation options should now be set to error, warn or ignore rather than true or false. In previous versions, some validators caused errors to be thrown, while some issued warnings. This change brings consistency to validator behavior.

• The allowResolversNotInSchema has been renamed to requireResolversToMatchSchema, to harmonize the naming convention of all the validators. The default setting of requireResolversToMatchSchema is error, matching the previous behavior.

Schema Delegation (delegateToSchema & @graphql-tools/delegate)

• The delegateToSchema return value has matured and been formalized as an ExternalObject, in which all errors are integrated into the GraphQL response, preserving their initial path. Those advanced users accessing the result directly will note the change in error handling. This also allows for the deprecation of unnecessary helper functions including slicedError, getErrors, getErrorsByPathSegment functions. Only external errors with missing or invalid paths must still be preserved by annotating the remote object with special properties. The new getUnpathedErrors function is therefore necessary for retrieving only these errors. Note also the new annotateExternalObject and mergeExternalObjects functions, as well as the renaming of handleResult to resolveExternalValue.

• Transform types and the applySchemaTransforms are now relocated to the delegate package; applyRequestTransforms/applyResultTransforms functions have been deprecated, however, as this functionality has been replaced since v6 by the Transformer abstraction.

• The transformRequest/transformResult methods are now provided additional delegationContext and transformationContext arguments — these were introduced in v6, but previously optional.

• The transformSchema method may wish to create additional delegating resolvers and so it is now provided the subschemaConfig and final (non-executable) transformedSchema parameters. As in v6, the transformSchema is kicked off once to produce the non-executable version, and then, if a wrapping schema is being generated, proxying resolvers are created with access to the (non-executable) initial result. In v7, the individual transformSchema methods also get access to the result of the first run, if necessary, they can create additional wrapping schema proxying resolvers.

• applySchemaTransforms parameters have been updated to match and support the transformSchema parameters above.

Remote Schemas & Wrapping (wrapSchema, makeRemoteExecutableSchema, and @graphql-tools/wrap)

• wrapSchema and generateProxyingResolvers now only take a single options argument with named properties of type SubschemaConfig. The previously possible shorthand version with the first argument consisting of a GraphQLSchema and the second argument representing the transforms should be reworked as a SubschemaConfig object.

• Similarly, the ICreateProxyingResolverOptions interface that provides the options for the createProxyingResolver property of SubschemaConfig options has been adjusted. The schema property previously could be set to a GraphQLSchema or a SubschemaConfig object. This property has been removed in favor of a subschemaConfig property that will always be a SubschemaConfig object. The transforms property has been removed; transforms should be included within the SubschemaConfig object.`

• The format of the wrapping schema has solidified. All non-root fields are expected to use identical resolvers, either defaultMergedResolver or a custom equivalent, with root fields doing the hard work of proxying. Support for custom merged resolvers through createMergedResolver has been deprecated, as custom merging resolvers conflict when using stitching’s type merging, where resolvers are expected to be identical across subschemas.

• The WrapFields transform’s wrappingResolver option has been removed, as this complicates multiple wrapping layers, as well as planned functionality to wrap subscription root fields in potentially multiple layers, as the wrapping resolvers may be different in different layers. Modifying resolvers can still be performed by use of an additional transform such as TransformRootFields or TransformObjectFields.

• The ExtendSchema transform has been removed, as it is conceptually simpler just to use stitchSchemas with one subschema.

• The ReplaceFieldsWithFragment, AddFragmentsByField, AddSelectionSetsByField, and AddMergedTypeSelectionSets transforms has been removed, as they are superseded by the AddSelectionSets and VisitSelectionSets transforms. The AddSelectionSets purposely takes parsed SDL rather than strings, to nudge end users to parse these strings at build time (when possible), rather than at runtime. Parsing of selection set strings can be performed using the parseSelectionSet function from @graphql-tools/utils.

Schema Stitching (stitchSchemas & @graphql-tools/stitch)

• stitchSchemas’s mergeTypes option is now true by default! This causes the onTypeConflict option to be ignored by default. To use onTypeConflict to select a specific type instead of simply merging, simply set mergeTypes to false.

• schemas argument has been deprecated, use subschemas, typeDefs, or types, depending on what you are stitching.

• When using batch delegation in type merging, the argsFromKeys function is now set only via the argsFromKeys property. Previously, if argsFromKeys was absent, it could be read from args.

• Support for fragment hints has been removed in favor of selection set hints. To migrate you need to replace your resolver fragment hints for selection set hints eg.:

Type: {
  fragment: '... on Type { id }'
  resolve: () => { ... }
}

for

Type: {
  selectionSet: '{ id }'
  resolve: () => { ... }
}

• stitchSchemas now processes all GraphQLSchema and SubschemaConfig subschema input into new Subschema objects, handling schema config directives such aso@computed as well as generating the final transformed schema, stored as the transformedSchema property, if transforms are used. Signatures of the onTypeConflict, fieldConfigMerger, and inputFieldConfigMerger have been updated to include metadata related to the original and transformed subschemas. Note the property name change for onTypeConflict from schema to subschema.

Mocking (addMocksToSchema and @graphql-tools/mock)

• Mocks returning objects with fields set as functions are now operating according to the upstream graphql-js convention, i.e. these functions take three arguments, args, context, and info with parent available as this rather than as the first argument.

Other Utilities (@graphql-tools/utils)

• filterSchema’s fieldFilter will now filter all fields across Object, Interface, and Input types. For the previous Object-only behavior, switch to the objectFieldFilter option.
• Unused fieldNodes utility functions have been removed.
• Unused typeContainsSelectionSet function has been removed, and typesContainSelectionSet has been moved to the stitch package.
• Unnecessary Operation type has been removed in favor of OperationTypeNode from upstream graphql-js.
• As above, applySchemaTransforms/applyRequestTransforms/applyResultTransforms have been removed from the utils package, as they are implemented elsewhere or no longer necessary.

Upgrading from v4/v5

If you are using GraphQL Tools v4/v5, additional changes are necessary.

Monorepo Design

You can still import functions directly from graphql-tools, but we encourage you to instead import functions from specific packages under the new mono repo design: @graphql-tools/schema, @graphql-tools/merge, etc.

Schema Generation and Decoration API (@graphql-tools/schema)

The majority of schema modification functions now return new, altered schemas rather than modifying the original schema in place. Note that several functions have been renamed as ResolveFunctions and MockFunctions have been shortened to Resolvers and Mocks throughout the code base and documentation:

• makeExecutableSchema
• addResolveFunctionsToSchema => addResolversToSchema
• attachDirectiveResolvers
• addSchemaLevelResolveFunctions => addSchemaLevelResolver
• addCatchUndefinedToSchema
• addErrorLoggingToSchema
• addMockFunctionsToSchema => addMocksToSchema

Schema modification functions operating on fields now similarly take a schema as a parameter and return a new schema, rather than modifying the passed in typeMap (and requiring manual schema healing).

• appendObjectFields
• removeObjectFields

The addConnectorsToContext has been deprecated in favor of manually attaching connectors to context, see #140.

Abstract types that use resolveType properties to return an actual type rather than a type name may be unstable when using graphql-tools, as these types are hidden from the type map and cannot be recreated. These resolveType resolvers should be relatively easy to rewrite to use the name of a known GraphQLObject type included within the schema’s type map. This will soon be the recommended approach in upstream graphql-js as well, see #2279.

Remote Schemas & Wrapping (wrapSchema, makeRemoteExecutableSchema, and @graphql-tools/wrap)

• Remote schema wrapping is now accomplished by using executors and subscribers rather than fetchers and links. Functions that convert links to executors/subscribers are included with @graphql-tools/links. See the docs.

• Transform<*>Field Transforms now all take a fieldTransformer with altered FieldTransformer type. A FieldTransformer receives a field config as an argument rather than a field, so that library users are spared having to call fieldToFieldConfig. A FieldTransformer can return an array of type [string, GraphQLFieldConfig<any, any>] instead of an object { name: string, field: GraphQLFieldConfig<any, any> } if it wishes to rename the field, the tuple is less verbose — and the object is misnamed, it should be { newName, newFieldConfig }.

Schema Stitching (stitchSchemas & @graphql-tools/stitch)

• Stitching has been renamed (mergeSchemas => stitchSchemas)
• resolvers parameter passed to stitchSchemas match type signature of resolvers passed to makeExecutableSchema (and can no longer be functions). Stitching metadata stored within “mergeInfo” may still be accessed within each resolver under info.schema.extensions.stitchingInfo.
• Custom proxying resolvers take an options object instead of individual parameters, a breaking change from v5, when the custom proxying resolvers were introduced.

Schema Delegation (delegateToSchema & @graphql-tools/delegate)

• As above, mergeInfo in GraphQLResolveInfo has been replaced by stitchingInfo in GraphQLSchemas extensions.
• delegateToSchema is not available in mergeInfo or stitchingInfo anymore. Simply import the delegateToSchema function from the delegate package instead.

Other Utilities (@graphql-tools/utils)

• Polyfills for GraphQL versions earlier than 14.2 have been removed, including toConfig
• fieldToFieldConfig and inputFieldToInputFieldConfig functionality is now exported separately, although library users should ideally not have to use them.