Executor handles nil FieldEntry values

Sources/Apollo/Collection+Helpers.swift

@@ -3,27 +3,27 @@ import Foundation
 // MARK: - Unzipping
 // MARK: Arrays of tuples to tuples of arrays
 
-public func unzip<Element1, Element2>(_ array: [(Element1, Element2)]) -> ([Element1], [Element2]) {
+public func unzip<Element1, Element2>(_ array: [(Element1?, Element2?)]) -> ([Element1], [Element2]) {
   var array1: [Element1] = []
   var array2: [Element2] = []
 
-  for element in array {
-    array1.append(element.0)
-    array2.append(element.1)
+  for elements in array {
+    if let element1 = elements.0 { array1.append(element1) }
+    if let element2 = elements.1 { array2.append(element2) }
   }
 
   return (array1, array2)
 }
 
-public func unzip<Element1, Element2, Element3>(_ array: [(Element1, Element2, Element3)]) -> ([Element1], [Element2], [Element3]) {
+public func unzip<Element1, Element2, Element3>(_ array: [(Element1?, Element2?, Element3?)]) -> ([Element1], [Element2], [Element3]) {
   var array1: [Element1] = []
   var array2: [Element2] = []
   var array3: [Element3] = []
 
-  for element in array {
-    array1.append(element.0)
-    array2.append(element.1)
-    array3.append(element.2)
+  for elements in array {
+    if let element1 = elements.0 { array1.append(element1) }
+    if let element2 = elements.1 { array2.append(element2) }
+    if let element3 = elements.2 { array3.append(element3) }
   }
 
   return (array1, array2, array3)

Sources/Apollo/GraphQLDependencyTracker.swift

@@ -17,7 +17,8 @@ final class GraphQLDependencyTracker: GraphQLResultAccumulator {
     dependentKeys.insert(info.cachePath.joined)
   }
 
-  func accept(fieldEntry: Void, info: FieldExecutionInfo) {
+  func accept(fieldEntry: Void, info: FieldExecutionInfo) -> ()? {
+    return ()
   }
 
   func accept(fieldEntries: [Void], info: ObjectExecutionInfo) {

Sources/Apollo/GraphQLExecutor.swift

@@ -213,7 +213,7 @@ final class GraphQLExecutor {
     do {
       let groupedFields = try groupFields(selections, on: object, info: info)
 
-      var fieldEntries: [PossiblyDeferred<Accumulator.FieldEntry>] = []
+      var fieldEntries: [PossiblyDeferred<Accumulator.FieldEntry?>] = []
       fieldEntries.reserveCapacity(groupedFields.count)
 
       for (_, fields) in groupedFields {
@@ -223,7 +223,7 @@ final class GraphQLExecutor {
         fieldEntries.append(fieldEntry)
       }
 
-      return lazilyEvaluateAll(fieldEntries).map {
+      return compactLazilyEvaluateAll(fieldEntries).map {
         try accumulator.accept(fieldEntries: $0, info: info)
       }
 
@@ -320,7 +320,7 @@ final class GraphQLExecutor {
     fields: FieldExecutionInfo,
     on object: JSONObject,
     accumulator: Accumulator
-  ) -> PossiblyDeferred<Accumulator.FieldEntry> {
+  ) -> PossiblyDeferred<Accumulator.FieldEntry?> {
     var fieldInfo = fields
 
     if shouldComputeCachePath {

Sources/Apollo/GraphQLResponseGenerator.swift

@@ -17,7 +17,7 @@ final class GraphQLResponseGenerator: GraphQLResultAccumulator {
     return childObject
   }
 
-  func accept(fieldEntry: JSONValue, info: FieldExecutionInfo) -> (key: String, value: JSONValue) {
+  func accept(fieldEntry: JSONValue, info: FieldExecutionInfo) -> (key: String, value: JSONValue)? {
     return (info.responseKeyForField, fieldEntry)
   }
 

Sources/Apollo/GraphQLResultAccumulator.swift

@@ -9,7 +9,7 @@ protocol GraphQLResultAccumulator: AnyObject {
   func accept(list: [PartialResult], info: FieldExecutionInfo) throws -> PartialResult
   func accept(childObject: ObjectResult, info: FieldExecutionInfo) throws -> PartialResult
 
-  func accept(fieldEntry: PartialResult, info: FieldExecutionInfo) throws -> FieldEntry
+  func accept(fieldEntry: PartialResult, info: FieldExecutionInfo) throws -> FieldEntry?
   func accept(fieldEntries: [FieldEntry], info: ObjectExecutionInfo) throws -> ObjectResult
 
   func finish(rootValue: ObjectResult) throws -> FinalResult
@@ -25,7 +25,7 @@ func zip<Accumulator1: GraphQLResultAccumulator, Accumulator2: GraphQLResultAccu
 
 final class Zip2Accumulator<Accumulator1: GraphQLResultAccumulator, Accumulator2: GraphQLResultAccumulator>: GraphQLResultAccumulator {
   typealias PartialResult = (Accumulator1.PartialResult, Accumulator2.PartialResult)
-  typealias FieldEntry = (Accumulator1.FieldEntry, Accumulator2.FieldEntry)
+  typealias FieldEntry = (Accumulator1.FieldEntry?, Accumulator2.FieldEntry?)
   typealias ObjectResult = (Accumulator1.ObjectResult, Accumulator2.ObjectResult)
   typealias FinalResult = (Accumulator1.FinalResult, Accumulator2.FinalResult)
 
@@ -58,7 +58,7 @@ final class Zip2Accumulator<Accumulator1: GraphQLResultAccumulator, Accumulator2
             try accumulator2.accept(childObject: childObject.1, info: info))
   }
 
-  func accept(fieldEntry: PartialResult, info: FieldExecutionInfo) throws -> FieldEntry {
+  func accept(fieldEntry: PartialResult, info: FieldExecutionInfo) throws -> FieldEntry? {
     return (try accumulator1.accept(fieldEntry: fieldEntry.0, info: info),
             try accumulator2.accept(fieldEntry: fieldEntry.1, info: info))
   }
@@ -77,7 +77,7 @@ final class Zip2Accumulator<Accumulator1: GraphQLResultAccumulator, Accumulator2
 
 final class Zip3Accumulator<Accumulator1: GraphQLResultAccumulator, Accumulator2: GraphQLResultAccumulator, Accumulator3: GraphQLResultAccumulator>: GraphQLResultAccumulator {
   typealias PartialResult = (Accumulator1.PartialResult, Accumulator2.PartialResult, Accumulator3.PartialResult)
-  typealias FieldEntry = (Accumulator1.FieldEntry, Accumulator2.FieldEntry, Accumulator3.FieldEntry)
+  typealias FieldEntry = (Accumulator1.FieldEntry?, Accumulator2.FieldEntry?, Accumulator3.FieldEntry?)
   typealias ObjectResult = (Accumulator1.ObjectResult, Accumulator2.ObjectResult, Accumulator3.ObjectResult)
   typealias FinalResult = (Accumulator1.FinalResult, Accumulator2.FinalResult, Accumulator3.FinalResult)
 
@@ -119,7 +119,7 @@ final class Zip3Accumulator<Accumulator1: GraphQLResultAccumulator, Accumulator2
             try accumulator3.accept(childObject: childObject.2, info: info))
   }
 
-  func accept(fieldEntry: PartialResult, info: FieldExecutionInfo) throws -> FieldEntry {
+  func accept(fieldEntry: PartialResult, info: FieldExecutionInfo) throws -> FieldEntry? {
     return (try accumulator1.accept(fieldEntry: fieldEntry.0, info: info),
             try accumulator2.accept(fieldEntry: fieldEntry.1, info: info),
             try accumulator3.accept(fieldEntry: fieldEntry.2, info: info))

Sources/Apollo/GraphQLResultNormalizer.swift

@@ -19,7 +19,7 @@ final class GraphQLResultNormalizer: GraphQLResultAccumulator {
     return childObject
   }
 
-  func accept(fieldEntry: JSONValue, info: FieldExecutionInfo) -> (key: String, value: JSONValue) {
+  func accept(fieldEntry: JSONValue, info: FieldExecutionInfo) -> (key: String, value: JSONValue)? {
     return (info.cacheKeyForField, fieldEntry)
   }
 

Sources/Apollo/GraphQLSelectionSetMapper.swift

@@ -18,22 +18,23 @@ final class GraphQLSelectionSetMapper<SelectionSet: AnySelectionSet>: GraphQLRes
     return list
   }
 
-  func accept(childObject: [String : Any?], info: FieldExecutionInfo) throws -> JSONValue? {
+  func accept(childObject: JSONObject, info: FieldExecutionInfo) throws -> JSONValue? {
     return childObject
   }
 
-  func accept(fieldEntry: JSONValue?, info: FieldExecutionInfo) -> (key: String, value: JSONValue?) {
+  func accept(fieldEntry: JSONValue?, info: FieldExecutionInfo) -> (key: String, value: JSONValue)? {
+    guard let fieldEntry = fieldEntry else { return nil }
     return (info.responseKeyForField, fieldEntry)
   }
 
   func accept(
-    fieldEntries: [(key: String, value: JSONValue?)],
+    fieldEntries: [(key: String, value: JSONValue)],
     info: ObjectExecutionInfo
-  ) throws -> [String: Any?] {
+  ) throws -> JSONObject {
     return .init(fieldEntries, uniquingKeysWith: { (_, last) in last })
   }
 
-  func finish(rootValue: [String: Any?]) -> SelectionSet {
+  func finish(rootValue: JSONObject) -> SelectionSet {
     return SelectionSet.init(data: ResponseDict(rootValue))
   }
 }

Sources/Apollo/PossiblyDeferred.swift

@@ -10,6 +10,16 @@ func lazilyEvaluateAll<Value>(_ elements: [PossiblyDeferred<Value>]) -> Possibly
   }
 }
 
+/// Lazily evaluates an array of possibly deferred optional values, filtering out any nil values.
+/// - Parameters:
+///   - elements: An array of possibly deferred values
+/// - Returns: A deferred array with the result of evaluating each element.
+func compactLazilyEvaluateAll<Value>(_ elements: [PossiblyDeferred<Value?>]) -> PossiblyDeferred<[Value]> {
+  return .deferred {
+    try elements.compactMap { try $0.get() }
+  }
+}
+
 /// A possibly deferred value that represents either an immediate success or failure value, or a deferred
 /// value that is evaluated lazily when needed by invoking a throwing closure.
 enum PossiblyDeferred<Value> {

Sources/ApolloAPI/CodegenV1/ResponseDict.swift

@@ -1,9 +1,9 @@
 /// A structure that wraps the underlying data dictionary used by `SelectionSet`s.
 public struct ResponseDict {
 
-  let data: [String: Any?]
+  let data: JSONObject
 
-  public init(_ data: [String: Any?]) {
+  public init(_ data: JSONObject) {
     self.data = data
   }
 
@@ -16,17 +16,17 @@ public struct ResponseDict {
   }
 
   public subscript<T: SelectionSet>(_ key: String) -> T {
-    let objectData = data[key] as! [String: Any]
+    let objectData = data[key] as! JSONObject
     return T.init(data: ResponseDict(objectData))
   }
 
   public subscript<T: SelectionSet>(_ key: String) -> T? {
-    guard let objectData = data[key] as? [String: Any] else { return nil }
+    guard let objectData = data[key] as? JSONObject else { return nil }
     return T.init(data: ResponseDict(objectData))
   }
 
   public subscript<T: SelectionSet>(_ key: String) -> [T] {
-    let objectData = data[key] as! [[String: Any]]
+    let objectData = data[key] as! [JSONObject]
     return objectData.map { T.init(data: ResponseDict($0)) }
   }
 

Sources/ApolloAPI/CodegenV1/SchemaConfiguration.swift

@@ -3,7 +3,7 @@ public protocol SchemaConfiguration {
 }
 
 extension SchemaConfiguration {
-  public static func cacheKey(for data: [String: JSONValue]) -> CacheKey? {
+  public static func cacheKey(for data: JSONObject) -> CacheKey? {
     guard let __typename = data["__typename"] as? String,
           let keyString = cacheKeyString(for: data, withTypename: __typename) else {
       return nil
@@ -12,7 +12,7 @@ extension SchemaConfiguration {
   }
 
   private static func cacheKeyString(
-    for data: [String: JSONValue],
+    for data: JSONObject,
     withTypename __typename: String
   ) -> String? {
     if let objectType = objectType(forTypename: __typename),
@@ -29,10 +29,10 @@ extension SchemaConfiguration {
 }
 
 public protocol ObjectCacheKeyResolver {
-  static func cacheKey(for: [String: JSONValue]) -> String?
+  static func cacheKey(for: JSONObject) -> String?
 }
 
 public protocol SchemaUnknownTypeMapper {
-  static func cacheKeyForUnknownType(withTypename: String, data: [String: JSONValue]) -> String?
+  static func cacheKeyForUnknownType(withTypename: String, data: JSONObject) -> String?
 }