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Migration

3 to 4

NIO removal

All NIO-based arguments and return types were removed, including all EventLoopGroup and EventLoopFuture parameters.

As such, all execute and subscribe calls should have the eventLoopGroup argument removed, and the await keyword should be used.

Also, all resolver closures must remove the eventLoopGroup argument, and all that return an EventLoopFuture should be converted to an async function.

The documentation here will be very helpful in the conversion: https://www.swift.org/documentation/server/guides/libraries/concurrency-adoption-guidelines.html

ConcurrentDispatchFieldExecutionStrategy

This was changed to ConcurrentFieldExecutionStrategy, and takes no parameters.

EventStream removal

The EventStream abstraction used to provide pre-concurrency subscription support has been removed. This means that graphqlSubscribe(...).stream will now be an AsyncThrowingStream<GraphQLResult, Error> type, instead of an EventStream type, and that downcasting to ConcurrentEventStream is no longer necessary.

SubscriptionResult removal

The SubscriptionResult type was removed, and graphqlSubscribe now returns a true Swift Result type.

Instrumentation removal

The Instrumentation type has been removed, with anticipated support for tracing using swift-distributed-tracing. instrumentation arguments must be removed from graphql and graphqlSubscribe calls.

AST Node set

The deprecated Node.set(value: Node?, key: String) function was removed in preference of the Node.set(value _: NodeResult?, key _: String). Change any calls from node.set(value: node, key: string) to node.set(.node(node), string).

2 to 3

TypeReference removal

The GraphQLTypeReference type was removed in v3.0.0, since it was made unnecessary by introducing closure-based field API that allows the package to better control the order of type resolution.

To remove GraphQLTypeReference, you can typically just replace it with a reference to the GraphQLObjectType instance:

// Before
let object1 = try GraphQLObjectType(
  name: "Object1"
)
let object2 = try GraphQLObjectType(
  name: "Object2"
  fields: ["object1": GraphQLField(type: GraphQLTypeReference("Object1"))]
)

// After
let object1 = try GraphQLObjectType(
  name: "Object1"
)
let object2 = try GraphQLObjectType(
  name: "Object2"
  fields: ["object1": GraphQLField(type: object1)]
)

For more complex cyclic or recursive types, simply create the types first and assign the fields property afterward. Here's an example:

// Before
let object1 = try GraphQLObjectType(
  name: "Object1"
  fields: ["object2": GraphQLField(type: GraphQLTypeReference("Object2"))]
)
let object2 = try GraphQLObjectType(
  name: "Object2"
  fields: ["object1": GraphQLField(type: GraphQLTypeReference("Object1"))]
)

// After
let object1 = try GraphQLObjectType(name: "Object1")
let object2 = try GraphQLObjectType(name: "Object2")
object1.fields = { [weak object2] in
    guard let object2 = object2 else { return [:] }
    return ["object2": GraphQLField(type: object2)]
}
object2.fields = { [weak object1] in
    guard let object1 = object1 else { return [:] }
    return ["object1": GraphQLField(type: object1)]
}

Note that this also gives you the chance to explicitly handle the memory cycle that cyclic types cause as well.

Type Definition Arrays

The following type properties were changed from arrays to closures. To get the array version, in most cases you can just call the get-style function (i.e. for GraphQLObject.fields, use GraphQLObject.getFields()):

  • GraphQLObjectType.fields
  • GraphQLObjectType.interfaces
  • GraphQLInterfaceType.fields
  • GraphQLInterfaceType.interfaces
  • GraphQLUnionType.types
  • GraphQLInputObjectType.fields

Directive description is optional

GraphQLDirective has changed from a struct to a class, and its description property is now optional.

GraphQL type codability

With GraphQL type definitions now including closures, many of the objects in Definition are no longer codable. If you are depending on codability, you can conform the type appropriately in your downstream package.