feat!: Hides execution strategies, applying spec specified ones

Author: NeedleInAJayStack

MIGRATION.md

@@ -16,9 +16,10 @@ The documentation here will be very helpful in the conversion: https://www.swift
 
 With the conversion from NIO to Swift Concurrency, types used across async boundaries should conform to `Sendable` to avoid errors and warnings. This includes the Swift types and functions that back the GraphQL schema. For more details on the conversion, see the [Sendable documentation](https://developer.apple.com/documentation/swift/sendable).
 
-### `ConcurrentDispatchFieldExecutionStrategy`
+### `ExecutionStrategy` argument removals
+
+The `queryStrategy`, `mutationStrategy`, and `subscriptionStrategy` arguments have been removed from `graphql` and `graphqlSubscribe`. Instead Queries and Subscriptions are executed in parallel and Mutations are executed serially, [as required by the spec](https://spec.graphql.org/October2021/#sec-Mutation).
 
-This was changed to `ConcurrentFieldExecutionStrategy`, and takes no parameters.
 
 ### EventStream removal
 

Sources/GraphQL/Execution/Execute.swift

@@ -28,9 +28,10 @@ import OrderedCollections
  * and the fragments defined in the query document
  */
 public final class ExecutionContext: @unchecked Sendable {
-    let queryStrategy: QueryFieldExecutionStrategy
-    let mutationStrategy: MutationFieldExecutionStrategy
-    let subscriptionStrategy: SubscriptionFieldExecutionStrategy
+    let queryStrategy: QueryFieldExecutionStrategy = ConcurrentFieldExecutionStrategy()
+    let mutationStrategy: MutationFieldExecutionStrategy = SerialFieldExecutionStrategy()
+    let subscriptionStrategy: SubscriptionFieldExecutionStrategy =
+        ConcurrentFieldExecutionStrategy()
     public let schema: GraphQLSchema
     public let fragments: [String: FragmentDefinition]
     public let rootValue: any Sendable
@@ -59,9 +60,6 @@ public final class ExecutionContext: @unchecked Sendable {
     }
 
     init(
-        queryStrategy: QueryFieldExecutionStrategy,
-        mutationStrategy: MutationFieldExecutionStrategy,
-        subscriptionStrategy: SubscriptionFieldExecutionStrategy,
         schema: GraphQLSchema,
         fragments: [String: FragmentDefinition],
         rootValue: any Sendable,
@@ -70,9 +68,6 @@ public final class ExecutionContext: @unchecked Sendable {
         variableValues: [String: Map],
         errors: [GraphQLError]
     ) {
-        self.queryStrategy = queryStrategy
-        self.mutationStrategy = mutationStrategy
-        self.subscriptionStrategy = subscriptionStrategy
         self.schema = schema
         self.fragments = fragments
         self.rootValue = rootValue
@@ -179,10 +174,7 @@ public struct ConcurrentFieldExecutionStrategy: QueryFieldExecutionStrategy,
  * If the arguments to this func do not result in a legal execution context,
  * a GraphQLError will be thrown immediately explaining the invalid input.
  */
-func execute(
-    queryStrategy: QueryFieldExecutionStrategy,
-    mutationStrategy: MutationFieldExecutionStrategy,
-    subscriptionStrategy: SubscriptionFieldExecutionStrategy,
+public func execute(
     schema: GraphQLSchema,
     documentAST: Document,
     rootValue: any Sendable,
@@ -196,9 +188,6 @@ func execute(
         // If a valid context cannot be created due to incorrect arguments,
         // this will throw an error.
         buildContext = try buildExecutionContext(
-            queryStrategy: queryStrategy,
-            mutationStrategy: mutationStrategy,
-            subscriptionStrategy: subscriptionStrategy,
             schema: schema,
             documentAST: documentAST,
             rootValue: rootValue,
@@ -247,9 +236,6 @@ func execute(
  * Throws a GraphQLError if a valid execution context cannot be created.
  */
 func buildExecutionContext(
-    queryStrategy: QueryFieldExecutionStrategy,
-    mutationStrategy: MutationFieldExecutionStrategy,
-    subscriptionStrategy: SubscriptionFieldExecutionStrategy,
     schema: GraphQLSchema,
     documentAST: Document,
     rootValue: any Sendable,
@@ -300,9 +286,6 @@ func buildExecutionContext(
     )
 
     return ExecutionContext(
-        queryStrategy: queryStrategy,
-        mutationStrategy: mutationStrategy,
-        subscriptionStrategy: subscriptionStrategy,
         schema: schema,
         fragments: fragments,
         rootValue: rootValue,

Sources/GraphQL/GraphQL.swift

@@ -59,9 +59,6 @@ public struct GraphQLErrors: Error, Sendable {
 /// may wish to separate the validation and execution phases to a static time
 /// tooling step, and a server runtime step.
 ///
-/// - parameter queryStrategy:        The field execution strategy to use for query requests
-/// - parameter mutationStrategy:     The field execution strategy to use for mutation requests
-/// - parameter subscriptionStrategy: The field execution strategy to use for subscription requests
 /// - parameter schema:               The GraphQL type system to use when validating and executing a
 /// query.
 /// - parameter request:              A GraphQL language formatted string representing the requested
@@ -83,9 +80,6 @@ public struct GraphQLErrors: Error, Sendable {
 /// and there will be an error inside `errors` specifying the reason for the failure and the path of
 /// the failed field.
 public func graphql(
-    queryStrategy: QueryFieldExecutionStrategy = SerialFieldExecutionStrategy(),
-    mutationStrategy: MutationFieldExecutionStrategy = SerialFieldExecutionStrategy(),
-    subscriptionStrategy: SubscriptionFieldExecutionStrategy = SerialFieldExecutionStrategy(),
     validationRules: [@Sendable (ValidationContext) -> Visitor] = [],
     schema: GraphQLSchema,
     request: String,
@@ -107,9 +101,6 @@ public func graphql(
     }
 
     return try await execute(
-        queryStrategy: queryStrategy,
-        mutationStrategy: mutationStrategy,
-        subscriptionStrategy: subscriptionStrategy,
         schema: schema,
         documentAST: documentAST,
         rootValue: rootValue,
@@ -122,9 +113,6 @@ public func graphql(
 /// This is the primary entry point function for fulfilling GraphQL operations
 /// by using persisted queries.
 ///
-/// - parameter queryStrategy:        The field execution strategy to use for query requests
-/// - parameter mutationStrategy:     The field execution strategy to use for mutation requests
-/// - parameter subscriptionStrategy: The field execution strategy to use for subscription requests
 /// - parameter queryRetrieval:       The PersistedQueryRetrieval instance to use for looking up
 /// queries
 /// - parameter queryId:              The id of the query to execute
@@ -145,9 +133,6 @@ public func graphql(
 /// and there will be an error inside `errors` specifying the reason for the failure and the path of
 /// the failed field.
 public func graphql<Retrieval: PersistedQueryRetrieval>(
-    queryStrategy: QueryFieldExecutionStrategy = SerialFieldExecutionStrategy(),
-    mutationStrategy: MutationFieldExecutionStrategy = SerialFieldExecutionStrategy(),
-    subscriptionStrategy: SubscriptionFieldExecutionStrategy = SerialFieldExecutionStrategy(),
     queryRetrieval: Retrieval,
     queryId: Retrieval.Id,
     rootValue: (any Sendable) = (),
@@ -164,9 +149,6 @@ public func graphql<Retrieval: PersistedQueryRetrieval>(
         return GraphQLResult(errors: validationErrors)
     case let .result(schema, documentAST):
         return try await execute(
-            queryStrategy: queryStrategy,
-            mutationStrategy: mutationStrategy,
-            subscriptionStrategy: subscriptionStrategy,
             schema: schema,
             documentAST: documentAST,
             rootValue: rootValue,
@@ -185,9 +167,6 @@ public func graphql<Retrieval: PersistedQueryRetrieval>(
 /// may wish to separate the validation and execution phases to a static time
 /// tooling step, and a server runtime step.
 ///
-/// - parameter queryStrategy:        The field execution strategy to use for query requests
-/// - parameter mutationStrategy:     The field execution strategy to use for mutation requests
-/// - parameter subscriptionStrategy: The field execution strategy to use for subscription requests
 /// - parameter schema:               The GraphQL type system to use when validating and executing a
 /// query.
 /// - parameter request:              A GraphQL language formatted string representing the requested
@@ -213,9 +192,6 @@ public func graphql<Retrieval: PersistedQueryRetrieval>(
 /// will be an error inside `errors` specifying the reason for the failure and the path of the
 /// failed field.
 public func graphqlSubscribe(
-    queryStrategy: QueryFieldExecutionStrategy = SerialFieldExecutionStrategy(),
-    mutationStrategy: MutationFieldExecutionStrategy = SerialFieldExecutionStrategy(),
-    subscriptionStrategy: SubscriptionFieldExecutionStrategy = SerialFieldExecutionStrategy(),
     validationRules: [@Sendable (ValidationContext) -> Visitor] = [],
     schema: GraphQLSchema,
     request: String,
@@ -237,9 +213,6 @@ public func graphqlSubscribe(
     }
 
     return try await subscribe(
-        queryStrategy: queryStrategy,
-        mutationStrategy: mutationStrategy,
-        subscriptionStrategy: subscriptionStrategy,
         schema: schema,
         documentAST: documentAST,
         rootValue: rootValue,

Sources/GraphQL/Subscription/Subscribe.swift

@@ -15,9 +15,6 @@ import OrderedCollections
  * representing the response stream.
  */
 func subscribe(
-    queryStrategy: QueryFieldExecutionStrategy,
-    mutationStrategy: MutationFieldExecutionStrategy,
-    subscriptionStrategy: SubscriptionFieldExecutionStrategy,
     schema: GraphQLSchema,
     documentAST: Document,
     rootValue: any Sendable,
@@ -26,9 +23,6 @@ func subscribe(
     operationName: String? = nil
 ) async throws -> Result<AsyncThrowingStream<GraphQLResult, Error>, GraphQLErrors> {
     let sourceResult = try await createSourceEventStream(
-        queryStrategy: queryStrategy,
-        mutationStrategy: mutationStrategy,
-        subscriptionStrategy: subscriptionStrategy,
         schema: schema,
         documentAST: documentAST,
         rootValue: rootValue,
@@ -49,9 +43,6 @@ func subscribe(
             // `marker protocol 'Sendable' cannot be used in a conditional cast`
             let rootValue = eventPayload as! (any Sendable)
             return try await execute(
-                queryStrategy: queryStrategy,
-                mutationStrategy: mutationStrategy,
-                subscriptionStrategy: subscriptionStrategy,
                 schema: schema,
                 documentAST: documentAST,
                 rootValue: rootValue,
@@ -87,9 +78,6 @@ func subscribe(
  * "Supporting Subscriptions at Scale" information in the GraphQL specification.
  */
 func createSourceEventStream(
-    queryStrategy: QueryFieldExecutionStrategy,
-    mutationStrategy: MutationFieldExecutionStrategy,
-    subscriptionStrategy: SubscriptionFieldExecutionStrategy,
     schema: GraphQLSchema,
     documentAST: Document,
     rootValue: any Sendable,
@@ -100,9 +88,6 @@ func createSourceEventStream(
     // If a valid context cannot be created due to incorrect arguments,
     // this will throw an error.
     let exeContext = try buildExecutionContext(
-        queryStrategy: queryStrategy,
-        mutationStrategy: mutationStrategy,
-        subscriptionStrategy: subscriptionStrategy,
         schema: schema,
         documentAST: documentAST,
         rootValue: rootValue,