[VertexAI] More Swift 6 (#14499)

Author: paulb777

.github/workflows/vertexai.yml

@@ -129,10 +129,14 @@ jobs:
     strategy:
       matrix:
         target: [ios]
-        os: [macos-14]
+        os: [macos-14, macos-15]
         include:
           - os: macos-14
             xcode: Xcode_15.2
+            warnings: --allow-warnings
+          - os: macos-15
+            xcode: Xcode_16.2
+            warnings:
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
@@ -144,7 +148,7 @@ jobs:
     - name: Xcode
       run: sudo xcode-select -s /Applications/${{ matrix.xcode }}.app/Contents/Developer
     - name: Build and test
-      run: scripts/third_party/travis/retry.sh scripts/pod_lib_lint.rb FirebaseVertexAI.podspec --platforms=${{ matrix.target }}
+      run: scripts/third_party/travis/retry.sh scripts/pod_lib_lint.rb FirebaseVertexAI.podspec --platforms=${{ matrix.target }} ${{ matrix.warnings }}
 
   sample:
     strategy:

FirebaseVertexAI/Sources/Chat.swift

@@ -17,7 +17,7 @@ import Foundation
 /// An object that represents a back-and-forth chat with a model, capturing the history and saving
 /// the context in memory between each message sent.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public class Chat {
+public final class Chat: Sendable {
   private let model: GenerativeModel
 
   /// Initializes a new chat representing a 1:1 conversation between model and user.
@@ -26,9 +26,28 @@ public class Chat {
     self.history = history
   }
 
+  private let historyLock = NSLock()
+  #if compiler(>=6)
+    private nonisolated(unsafe) var _history: [ModelContent] = []
+  #else
+    private var _history: [ModelContent] = []
+  #endif
   /// The previous content from the chat that has been successfully sent and received from the
   /// model. This will be provided to the model for each message sent as context for the discussion.
-  public var history: [ModelContent]
+  public var history: [ModelContent] {
+    get {
+      historyLock.withLock { _history }
+    }
+    set {
+      historyLock.withLock { _history = newValue }
+    }
+  }
+
+  private func appendHistory(contentsOf: [ModelContent]) {
+    historyLock.withLock {
+      _history.append(contentsOf: contentsOf)
+    }
+  }
 
   /// Sends a message using the existing history of this chat as context. If successful, the message
   /// and response will be added to the history. If unsuccessful, history will remain unchanged.
@@ -66,7 +85,7 @@ public class Chat {
     let toAdd = ModelContent(role: "model", parts: reply.parts)
 
     // Append the request and successful result to history, then return the value.
-    history.append(contentsOf: newContent)
+    appendHistory(contentsOf: newContent)
     history.append(toAdd)
     return result
   }
@@ -88,16 +107,16 @@ public class Chat {
   @available(macOS 12.0, *)
   public func sendMessageStream(_ content: [ModelContent]) throws
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
+    // Ensure that the new content has the role set.
+    let newContent: [ModelContent] = content.map(populateContentRole(_:))
+
+    // Send the history alongside the new message as context.
+    let request = history + newContent
+    let stream = try model.generateContentStream(request)
     return AsyncThrowingStream { continuation in
       Task {
         var aggregatedContent: [ModelContent] = []
 
-        // Ensure that the new content has the role set.
-        let newContent: [ModelContent] = content.map(populateContentRole(_:))
-
-        // Send the history alongside the new message as context.
-        let request = history + newContent
-        let stream = try model.generateContentStream(request)
         do {
           for try await chunk in stream {
             // Capture any content that's streaming. This should be populated if there's no error.
@@ -115,12 +134,11 @@ public class Chat {
         }
 
         // Save the request.
-        history.append(contentsOf: newContent)
+        appendHistory(contentsOf: newContent)
 
         // Aggregate the content to add it to the history before we finish.
-        let aggregated = aggregatedChunks(aggregatedContent)
-        history.append(aggregated)
-
+        let aggregated = self.aggregatedChunks(aggregatedContent)
+        self.history.append(aggregated)
         continuation.finish()
       }
     }

FirebaseVertexAI/Sources/FirebaseInfo.swift

@@ -14,13 +14,14 @@
 
 import Foundation
 
-import FirebaseAppCheckInterop
-import FirebaseAuthInterop
-import FirebaseCore
+// TODO: Remove `@preconcurrency` when possible.
+@preconcurrency import FirebaseAppCheckInterop
+@preconcurrency import FirebaseAuthInterop
+@preconcurrency import FirebaseCore
 
 /// Firebase data used by VertexAI
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-struct FirebaseInfo {
+struct FirebaseInfo: Sendable {
   let appCheck: AppCheckInterop?
   let auth: AuthInterop?
   let projectID: String

FirebaseVertexAI/Sources/FunctionCalling.swift

@@ -19,7 +19,7 @@ import Foundation
 /// This `FunctionDeclaration` is a representation of a block of code that can be used as a ``Tool``
 /// by the model and executed by the client.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public struct FunctionDeclaration {
+public struct FunctionDeclaration: Sendable {
   /// The name of the function.
   let name: String
 
@@ -55,7 +55,7 @@ public struct FunctionDeclaration {
 /// A `Tool` is a piece of code that enables the system to interact with external systems to perform
 /// an action, or set of actions, outside of knowledge and scope of the model.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public struct Tool {
+public struct Tool: Sendable {
   /// A list of `FunctionDeclarations` available to the model.
   let functionDeclarations: [FunctionDeclaration]?
 
@@ -89,7 +89,7 @@ public struct Tool {
 
 /// Configuration for specifying function calling behavior.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public struct FunctionCallingConfig {
+public struct FunctionCallingConfig: Sendable {
   /// Defines the execution behavior for function calling by defining the execution mode.
   enum Mode: String {
     case auto = "AUTO"
@@ -135,7 +135,7 @@ public struct FunctionCallingConfig {
 
 /// Tool configuration for any `Tool` specified in the request.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public struct ToolConfig {
+public struct ToolConfig: Sendable {
   let functionCallingConfig: FunctionCallingConfig?
 
   public init(functionCallingConfig: FunctionCallingConfig? = nil) {

FirebaseVertexAI/Sources/GenerateContentRequest.swift

@@ -15,7 +15,7 @@
 import Foundation
 
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-struct GenerateContentRequest {
+struct GenerateContentRequest: Sendable {
   /// Model name.
   let model: String
   let contents: [ModelContent]

FirebaseVertexAI/Sources/GenerationConfig.swift

@@ -17,7 +17,7 @@ import Foundation
 /// A struct defining model parameters to be used when sending generative AI
 /// requests to the backend model.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public struct GenerationConfig {
+public struct GenerationConfig: Sendable {
   /// Controls the degree of randomness in token selection.
   let temperature: Float?
 

FirebaseVertexAI/Sources/GenerativeAIRequest.swift

@@ -15,7 +15,7 @@
 import Foundation
 
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-protocol GenerativeAIRequest: Encodable {
+protocol GenerativeAIRequest: Sendable, Encodable {
   associatedtype Response: Decodable
 
   var url: URL { get }
@@ -26,7 +26,7 @@ protocol GenerativeAIRequest: Encodable {
 /// Configuration parameters for sending requests to the backend.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 // TODO(#14405): Make the `apiVersion` constructor public in Firebase 12 with a default of `.v1`.
-public struct RequestOptions {
+public struct RequestOptions: Sendable {
   /// The request’s timeout interval in seconds; if not specified uses the default value for a
   /// `URLRequest`.
   let timeout: TimeInterval

FirebaseVertexAI/Sources/GenerativeAIService.swift

@@ -69,7 +69,7 @@ struct GenerativeAIService {
 
   @available(macOS 12.0, *)
   func loadRequestStream<T: GenerativeAIRequest>(request: T)
-    -> AsyncThrowingStream<T.Response, Error> {
+    -> AsyncThrowingStream<T.Response, Error> where T: Sendable {
     return AsyncThrowingStream { continuation in
       Task {
         let urlRequest: URLRequest

FirebaseVertexAI/Sources/GenerativeModel.swift

@@ -19,7 +19,7 @@ import Foundation
 /// A type that represents a remote multimodal model (like Gemini), with the ability to generate
 /// content based on various input types.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public final class GenerativeModel {
+public final class GenerativeModel: Sendable {
   /// The resource name of the model in the backend; has the format "models/model-name".
   let modelResourceName: String
 

FirebaseVertexAI/Sources/Safety.swift

@@ -146,7 +146,7 @@ public struct SafetyRating: Equatable, Hashable, Sendable {
 /// A type used to specify a threshold for harmful content, beyond which the model will return a
 /// fallback response instead of generated content.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public struct SafetySetting {
+public struct SafetySetting: Sendable {
   /// Block at and beyond a specified ``SafetyRating/HarmProbability``.
   public struct HarmBlockThreshold: EncodableProtoEnum, Sendable {
     enum Kind: String {