[Distributed] decode init for DistributedActor

lib/AST/ASTContext.cpp

@@ -2943,6 +2943,29 @@ AnyFunctionType::Param swift::computeSelfParam(AbstractFunctionDecl *AFD,
       // inout self.
       if (!containerTy->hasReferenceSemantics())
         selfAccess = SelfAccessKind::Mutating;
+
+      // FIXME(distributed): pending swift-evolution, allow `self =` in class
+      //  inits in general.
+      //  See also: https://github.com/apple/swift/pull/19151 general impl
+      if (Ctx.LangOpts.EnableExperimentalDistributed) {
+        auto ext = dyn_cast<ExtensionDecl>(AFD->getDeclContext());
+        auto distProto =
+            Ctx.getProtocol(KnownProtocolKind::DistributedActor);
+        if (ext && ext->getExtendedNominal() &&
+            ext->getExtendedNominal()->getInterfaceType()
+                ->isEqual(distProto->getInterfaceType())) {
+          auto name = CD->getName();
+          auto params = name.getArgumentNames();
+          if (params.size() == 1 && params[0] == Ctx.Id_from) {
+            // FIXME(distributed): this is a workaround to allow init(from:) to
+            //  be implemented in AST by allowing the self to be mutable in the
+            //  decoding initializer. This should become a general Swift
+            //  feature, allowing this in all classes:
+            //  https://forums.swift.org/t/allow-self-x-in-class-convenience-initializers/15924
+            selfAccess = SelfAccessKind::Mutating;
+          }
+        }
+      }
     } else {
       // allocating constructors have metatype 'self'.
       isStatic = true;

stdlib/public/Distributed/ActorTransport.swift

@@ -48,7 +48,7 @@ public protocol ActorTransport: Sendable {
   ///
   /// Detecting liveness of such remote actors shall be offered / by transport libraries
   /// by other means, such as "watching an actor for termination" or similar.
-  func resolve<Act>(_ identity: AnyActorIdentity, as actorType: Act.Type) throws -> Act? // TODO(distributed): make just optional
+  func resolve<Act>(_ identity: AnyActorIdentity, as actorType: Act.Type) throws -> Act?
       where Act: DistributedActor
 
   // ==== ---------------------------------------------------------------------

stdlib/public/Distributed/DistributedActor.swift

@@ -93,16 +93,21 @@ extension DistributedActor {
 // ==== Codable conformance ----------------------------------------------------
 
 extension CodingUserInfoKey {
-    @available(SwiftStdlib 5.5, *)
-    static let actorTransportKey = CodingUserInfoKey(rawValue: "$dist_act_transport")!
+  @available(SwiftStdlib 5.5, *)
+  public static let actorTransportKey = CodingUserInfoKey(rawValue: "$dist_act_transport")!
 }
 
 @available(SwiftStdlib 5.5, *)
 extension DistributedActor {
   nonisolated public init(from decoder: Decoder) throws {
-//    let id = try AnyActorIdentity(from: decoder)
-//    self = try Self.resolve(id, using: transport) // FIXME: This is going to be solved by the init() work!!!!
-    fatalError("\(#function) is not implemented yet for distributed actors'")
+    guard let transport = decoder.userInfo[.actorTransportKey] as? ActorTransport else {
+      throw DistributedActorCodingError(message:
+        "Missing ActorTransport (for key .actorTransportKey) " +
+        "in Decoder.userInfo, while decoding \(Self.self).")
+    }
+
+    let id: AnyActorIdentity = try transport.decodeIdentity(from: decoder)
+    self = try Self.resolve(id, using: transport)
   }
 
   nonisolated public func encode(to encoder: Encoder) throws {
@@ -121,12 +126,14 @@ public protocol ActorIdentity: Sendable, Hashable, Codable {}
 
 @available(SwiftStdlib 5.5, *)
 public struct AnyActorIdentity: ActorIdentity, @unchecked Sendable, CustomStringConvertible {
+  public let underlying: Any
   @usableFromInline let _hashInto: (inout Hasher) -> ()
   @usableFromInline let _equalTo: (Any) -> Bool
   @usableFromInline let _encodeTo: (Encoder) throws -> ()
   @usableFromInline let _description: () -> String
 
   public init<ID>(_ identity: ID) where ID: ActorIdentity {
+    self.underlying = identity
     _hashInto = { hasher in identity
         .hash(into: &hasher)
     }

test/Distributed/Runtime/distributed_actor_decode.swift

@@ -0,0 +1,218 @@
+// RUN: %target-run-simple-swift(-Xfrontend -enable-experimental-distributed -parse-as-library) | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+import _Distributed
+
+@available(SwiftStdlib 5.5, *)
+distributed actor DA: CustomStringConvertible {
+  nonisolated var description: String {
+    "DA(\(self.id))"
+  }
+}
+
+// ==== Fake Transport ---------------------------------------------------------
+
+@available(SwiftStdlib 5.5, *)
+struct ActorAddress: ActorIdentity {
+  let address: String
+  init(parse address : String) {
+    self.address = address
+  }
+
+  // Explicit implementations to make our TestEncoder/Decoder simpler
+  init(from decoder: Decoder) throws {
+    let container = try decoder.singleValueContainer()
+    self.address = try container.decode(String.self)
+    print("decode ActorAddress -> \(self)")
+  }
+
+  func encode(to encoder: Encoder) throws {
+    print("encode \(self)")
+    var container = encoder.singleValueContainer()
+    try container.encode(self.address)
+  }
+}
+
+@available(SwiftStdlib 5.5, *)
+struct FakeTransport: ActorTransport {
+  func decodeIdentity(from decoder: Decoder) throws -> AnyActorIdentity {
+    print("FakeTransport.decodeIdentity from:\(decoder)")
+    let address = try ActorAddress(from: decoder)
+    return AnyActorIdentity(address)
+  }
+
+  func resolve<Act>(_ identity: AnyActorIdentity, as actorType: Act.Type) throws -> Act?
+      where Act: DistributedActor {
+    print("resolve type:\(actorType), address:\(identity)")
+    return nil
+  }
+
+  func assignIdentity<Act>(_ actorType: Act.Type) -> AnyActorIdentity
+      where Act: DistributedActor {
+    let address = ActorAddress(parse: "xxx")
+    print("assign type:\(actorType), address:\(address)")
+    return .init(address)
+  }
+
+  public func actorReady<Act>(_ actor: Act) where Act: DistributedActor {
+    print("ready actor:\(actor), address:\(actor.id)")
+  }
+
+  func resignIdentity(_ identity: AnyActorIdentity) {
+    print("resign address:\(identity)")
+  }
+}
+
+// ==== Test Coding ------------------------------------------------------------
+
+@available(SwiftStdlib 5.5, *)
+class TestEncoder: Encoder {
+  var codingPath: [CodingKey]
+  var userInfo: [CodingUserInfoKey: Any]
+
+  var data: String? = nil
+
+  init(transport: ActorTransport) {
+    self.codingPath = []
+    self.userInfo = [.actorTransportKey: transport]
+  }
+
+  func container<Key>(keyedBy type: Key.Type) -> KeyedEncodingContainer<Key> {
+    fatalError("Not implemented: \(#function)")
+  }
+
+  func unkeyedContainer() -> UnkeyedEncodingContainer {
+    fatalError("Not implemented: \(#function)")
+  }
+
+  func singleValueContainer() -> SingleValueEncodingContainer {
+    TestSingleValueEncodingContainer(parent: self)
+  }
+
+  class TestSingleValueEncodingContainer: SingleValueEncodingContainer {
+    let parent: TestEncoder
+    init(parent: TestEncoder) {
+      self.parent = parent
+    }
+
+    var codingPath: [CodingKey] = []
+
+    func encodeNil() throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: Bool) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: String) throws {
+
+    }
+    func encode(_ value: Double) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: Float) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: Int) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: Int8) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: Int16) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: Int32) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: Int64) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: UInt) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: UInt8) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: UInt16) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: UInt32) throws { fatalError("Not implemented: \(#function)") }
+    func encode(_ value: UInt64) throws { fatalError("Not implemented: \(#function)") }
+    func encode<T: Encodable>(_ value: T) throws {
+      print("encode: \(value)")
+      if let identity = value as? AnyActorIdentity {
+        self.parent.data =
+            (identity.underlying as! ActorAddress).address
+      }
+    }
+  }
+
+  func encode<Act: DistributedActor>(_ actor: Act) throws -> String {
+    try actor.encode(to: self)
+    return self.data!
+  }
+}
+
+@available(SwiftStdlib 5.5, *)
+class TestDecoder: Decoder {
+  let encoder: TestEncoder
+  let data: String
+
+  init(encoder: TestEncoder, transport: ActorTransport, data: String) {
+    self.encoder = encoder
+    self.userInfo = [.actorTransportKey: transport]
+    self.data = data
+  }
+
+  var codingPath: [CodingKey] = []
+  var userInfo: [CodingUserInfoKey : Any]
+
+  func container<Key>(keyedBy type: Key.Type) throws -> KeyedDecodingContainer<Key> where Key : CodingKey {
+    fatalError("Not implemented: \(#function)")
+  }
+  func unkeyedContainer() throws -> UnkeyedDecodingContainer {
+    fatalError("Not implemented: \(#function)")
+  }
+  func singleValueContainer() throws -> SingleValueDecodingContainer {
+    TestSingleValueDecodingContainer(parent: self)
+  }
+
+  class TestSingleValueDecodingContainer: SingleValueDecodingContainer {
+    let parent: TestDecoder
+    init(parent: TestDecoder) {
+      self.parent = parent
+    }
+
+    var codingPath: [CodingKey] = []
+    func decodeNil() -> Bool { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: Bool.Type) throws -> Bool { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: String.Type) throws -> String {
+      print("decode String -> \(self.parent.data)")
+      return self.parent.data
+    }
+    func decode(_ type: Double.Type) throws -> Double { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: Float.Type) throws -> Float { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: Int.Type) throws -> Int { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: Int8.Type) throws -> Int8 { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: Int16.Type) throws -> Int16 { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: Int32.Type) throws -> Int32 { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: Int64.Type) throws -> Int64 { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: UInt.Type) throws -> UInt { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: UInt8.Type) throws -> UInt8 { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: UInt16.Type) throws -> UInt16 { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: UInt32.Type) throws -> UInt32 { fatalError("Not implemented: \(#function)") }
+    func decode(_ type: UInt64.Type) throws -> UInt64 { fatalError("Not implemented: \(#function)") }
+    func decode<T>(_ type: T.Type) throws -> T where T : Decodable { fatalError("Not implemented: \(#function)") }
+  }
+}
+
+// ==== Execute ----------------------------------------------------------------
+
+@available(SwiftStdlib 5.5, *)
+func test() {
+  let transport = FakeTransport()
+
+  // CHECK: assign type:DA, address:ActorAddress(address: "xxx")
+  let da = DA(transport: transport)
+
+  // CHECK: encode: AnyActorIdentity(ActorAddress(address: "xxx"))
+  // CHECK: FakeTransport.decodeIdentity from:main.TestDecoder
+  let encoder = TestEncoder(transport: transport)
+  let data = try! encoder.encode(da)
+
+  // CHECK: decode String -> xxx
+  // CHECK: decode ActorAddress -> ActorAddress(address: "xxx")
+  let da2 = try! DA(from: TestDecoder(encoder: encoder, transport: transport, data: data))
+
+  // CHECK: decoded da2: DA(AnyActorIdentity(ActorAddress(address: "xxx")))
+  print("decoded da2: \(da2)")
+}
+
+@available(SwiftStdlib 5.5, *)
+@main struct Main {
+  static func main() async {
+    test()
+  }
+}