put errors into api methods

Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift

@@ -162,7 +162,7 @@ struct ErrorDetailsView: View {
   NavigationView {
     let _ = GenerateContentError.promptBlocked(
       response: GenerateContentResponse(candidates: [
-        CandidateResponse(content: ModelContent(role: "model", [
+        CandidateResponse(content: try! ModelContent(role: "model", [
           """
             A _hypothetical_ model response.
             Cillum ex aliqua amet aliquip labore amet eiusmod consectetur reprehenderit sit commodo.
@@ -183,7 +183,7 @@ struct ErrorDetailsView: View {
     let errorFinishedEarly = GenerateContentError.responseStoppedEarly(
       reason: .maxTokens,
       response: GenerateContentResponse(candidates: [
-        CandidateResponse(content: ModelContent(role: "model", [
+        CandidateResponse(content: try! ModelContent(role: "model", [
           """
             A _hypothetical_ model response.
             Cillum ex aliqua amet aliquip labore amet eiusmod consectetur reprehenderit sit commodo.

Examples/GenerativeAISample/ChatSample/Views/ErrorView.swift

@@ -37,7 +37,7 @@ struct ErrorView: View {
   NavigationView {
     let errorPromptBlocked = GenerateContentError.promptBlocked(
       response: GenerateContentResponse(candidates: [
-        CandidateResponse(content: ModelContent(role: "model", [
+        CandidateResponse(content: try! ModelContent(role: "model", [
           """
             A _hypothetical_ model response.
             Cillum ex aliqua amet aliquip labore amet eiusmod consectetur reprehenderit sit commodo.

Sources/GoogleAI/Chat.swift

@@ -40,9 +40,14 @@ public class Chat {
   /// - Parameter content: The new content to send as a single chat message.
   /// - Returns: The model's response if no error occurred.
   /// - Throws: A ``GenerateContentError`` if an error occurred.
-  public func sendMessage(_ content: [ModelContent]) async throws -> GenerateContentResponse {
+  public func sendMessage(_ content: @autoclosure () throws -> [ModelContent]) async throws -> GenerateContentResponse {
     // Ensure that the new content has the role set.
-    let newContent: [ModelContent] = content.map(populateContentRole(_:))
+    let newContent: [ModelContent]
+    do {
+      newContent = try content().map(populateContentRole(_:))
+    } catch(let underlying) {
+      throw GenerateContentError.internalError(underlying: underlying)
+    }
 
     // Send the history alongside the new message as context.
     let request = history + newContent
@@ -69,16 +74,25 @@ public class Chat {
   @available(macOS 12.0, *)
   public func sendMessageStream(_ parts: any PartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-    return sendMessageStream([ModelContent(parts: parts)])
+    return sendMessageStream(try [ModelContent(parts: parts)])
   }
 
   /// 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.
   /// - Parameter content: The new content to send as a single chat message.
   /// - Returns: A stream containing the model's response or an error if an error occurred.
   @available(macOS 12.0, *)
-  public func sendMessageStream(_ content: [ModelContent])
+  public func sendMessageStream(_ contentClosure: @autoclosure () throws -> [ModelContent])
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
+      let content: [ModelContent]
+      do {
+        content = try contentClosure()
+      } catch(let underlying) {
+        return AsyncThrowingStream { continuation in
+          continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
+        }
+      }
+
     return AsyncThrowingStream { continuation in
       Task {
         var aggregatedContent: [ModelContent] = []

Sources/GoogleAI/GenerativeModel.swift

@@ -141,7 +141,7 @@ public final class GenerativeModel {
   @available(macOS 12.0, *)
   public func generateContentStream(_ parts: any PartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-    return generateContentStream([ModelContent(parts: parts)])
+    return generateContentStream(try [ModelContent(parts: parts)])
   }
 
   /// Generates new content from input content given to the model as a prompt.
@@ -150,8 +150,17 @@ public final class GenerativeModel {
   /// - Returns: A stream wrapping content generated by the model or a ``GenerateContentError``
   ///     error if an error occurred.
   @available(macOS 12.0, *)
-  public func generateContentStream(_ content: [ModelContent])
+  public func generateContentStream(_ contentClosure: @autoclosure () throws -> [ModelContent])
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
+      let content: [ModelContent]
+      do {
+        content = try contentClosure()
+      } catch(let underlying) {
+        return AsyncThrowingStream { continuation in
+          continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
+        }
+      }
+
     let generateContentRequest = GenerateContentRequest(model: modelResourceName,
                                                         contents: content,
                                                         generationConfig: generationConfig,

Sources/GoogleAI/ModelContent.swift

@@ -104,14 +104,9 @@ public struct ModelContent: Codable, Equatable {
 
   /// Creates a new value from any data or `Array` of data interpretable as a
   /// ``Part``. See ``PartsRepresentable`` for types that can be interpreted as `Part`s.
-  public init(role: String? = "user", parts: some PartsRepresentable) {
+  public init(role: String? = "user", parts: some PartsRepresentable) throws {
     self.role = role
-    do {
-      try self.parts = parts.tryPartsValue()
-    } catch {
-      Logging.default.error("Error creating parts: \(error)")
-      self.parts = []
-    }
+    try self.parts = parts.tryPartsValue()
   }
 
   /// Creates a new value from a list of ``Part``s.
@@ -122,7 +117,7 @@ public struct ModelContent: Codable, Equatable {
 
   /// Creates a new value from any data interpretable as a ``Part``. See ``PartsRepresentable``
   /// for types that can be interpreted as `Part`s.
-  public init(role: String? = "user", _ parts: any PartsRepresentable...) {
-    self.init(role: role, parts: parts)
+  public init(role: String? = "user", _ parts: any PartsRepresentable...) throws {
+    try self.init(role: role, parts: parts)
   }
 }

Tests/GoogleAITests/ChatTests.swift

@@ -60,7 +60,7 @@ final class ChatTests: XCTestCase {
     XCTAssertEqual(chat.history[0].parts[0].text, input)
 
     let finalText = "1 2 3 4 5 6 7 8 9 10"
-    let assembledExpectation = ModelContent(role: "model", parts: finalText)
+    let assembledExpectation = try ModelContent(role: "model", parts: finalText)
     XCTAssertEqual(chat.history[0].parts[0].text, input)
     XCTAssertEqual(chat.history[1], assembledExpectation)
   }

Tests/GoogleAITests/GoogleAITests.swift

@@ -69,8 +69,8 @@ final class GoogleGenerativeAITests: XCTestCase {
         .generateContent([str, UIImage(), ModelContent.Part.text(str)])
       _ = try await genAI.generateContent(str, UIImage(), "def", UIImage())
       _ = try await genAI.generateContent([str, UIImage(), "def", UIImage()])
-      _ = try await genAI.generateContent([ModelContent("def", UIImage()),
-                                           ModelContent("def", UIImage())])
+      _ = try await genAI.generateContent([try ModelContent("def", UIImage()),
+                                           try ModelContent("def", UIImage())])
     #elseif canImport(AppKit)
       _ = try await genAI.generateContent(NSImage())
       _ = try await genAI.generateContent([NSImage()])
@@ -81,40 +81,40 @@ final class GoogleGenerativeAITests: XCTestCase {
     // PartsRepresentable combinations.
     let _ = ModelContent(parts: [.text(str)])
     let _ = ModelContent(role: "model", parts: [.text(str)])
-    let _ = ModelContent(parts: "Constant String")
-    let _ = ModelContent(parts: str)
-    let _ = ModelContent(parts: [str])
+    let _ = try ModelContent(parts: "Constant String")
+    let _ = try ModelContent(parts: str)
+    let _ = try ModelContent(parts: [str])
     // Note: without `as [any PartsRepresentable]` this will fail to compile with "Cannot convert
     // value of type `[Any]` to expected type `[any PartsRepresentable]`. Not sure if there's a
     // way we can get it to work.
-    let _ = ModelContent(parts: [str, ModelContent.Part.data(
+    let _ = try ModelContent(parts: [str, ModelContent.Part.data(
       mimetype: "foo",
       Data()
     )] as [any PartsRepresentable])
     #if canImport(UIKit)
-      _ = ModelContent(role: "user", parts: UIImage())
-      _ = ModelContent(role: "user", parts: [UIImage()])
+      _ = try ModelContent(role: "user", parts: UIImage())
+      _ = try ModelContent(role: "user", parts: [UIImage()])
       // Note: without `as [any PartsRepresentable]` this will fail to compile with "Cannot convert
       // value of type `[Any]` to expected type `[any PartsRepresentable]`. Not sure if there's a
       // way we can get it to work.
-      _ = ModelContent(parts: [str, UIImage()] as [any PartsRepresentable])
+      _ = try ModelContent(parts: [str, UIImage()] as [any PartsRepresentable])
       // Alternatively, you can explicitly declare the type in a variable and pass it in.
       let representable2: [any PartsRepresentable] = [str, UIImage()]
-      _ = ModelContent(parts: representable2)
-      _ = ModelContent(parts: [str, UIImage(),
+      _ = try ModelContent(parts: representable2)
+      _ = try ModelContent(parts: [str, UIImage(),
                                ModelContent.Part.text(str)] as [any PartsRepresentable])
     #elseif canImport(AppKit)
-      _ = ModelContent(role: "user", parts: NSImage())
-      _ = ModelContent(role: "user", parts: [NSImage()])
+      _ = try ModelContent(role: "user", parts: NSImage())
+      _ = try ModelContent(role: "user", parts: [NSImage()])
       // Note: without `as [any PartsRepresentable]` this will fail to compile with "Cannot convert
       // value of type `[Any]` to expected type `[any PartsRepresentable]`. Not sure if there's a
       // way we can get it to work.
-      _ = ModelContent(parts: [str, NSImage()] as [any PartsRepresentable])
+      _ = try ModelContent(parts: [str, NSImage()] as [any PartsRepresentable])
       // Alternatively, you can explicitly declare the type in a variable and pass it in.
       let representable2: [any PartsRepresentable] = [str, NSImage()]
-      _ = ModelContent(parts: representable2)
+      _ = try ModelContent(parts: representable2)
       _ =
-        ModelContent(parts: [str, NSImage(),
+        try ModelContent(parts: [str, NSImage(),
                              ModelContent.Part.text(str)] as [any PartsRepresentable])
     #endif
 
@@ -124,14 +124,14 @@ final class GoogleGenerativeAITests: XCTestCase {
       let _: CountTokensResponse = try await genAI.countTokens("What color is the Sky?",
                                                                UIImage())
       let _: CountTokensResponse = try await genAI.countTokens([
-        ModelContent("What color is the Sky?", UIImage()),
-        ModelContent(UIImage(), "What color is the Sky?", UIImage()),
+        try ModelContent("What color is the Sky?", UIImage()),
+        try ModelContent(UIImage(), "What color is the Sky?", UIImage()),
       ])
     #endif
 
     // Chat
     _ = genAI.startChat()
-    _ = genAI.startChat(history: [ModelContent(parts: "abc")])
+    _ = genAI.startChat(history: [try ModelContent(parts: "abc")])
   }
 
   // Result builder alternative