[Vertex AI] Add blockReasonMessage to PromptFeedback

Author: andrewheard

FirebaseVertexAI/Sources/GenerateContentResponse.swift

@@ -235,12 +235,17 @@ public struct PromptFeedback: Sendable {
   /// The reason a prompt was blocked, if it was blocked.
   public let blockReason: BlockReason?
 
+  /// A human-readable description of the ``blockReason``.
+  public let blockReasonMessage: String?
+
   /// The safety ratings of the prompt.
   public let safetyRatings: [SafetyRating]
 
   /// Initializer for SwiftUI previews or tests.
-  public init(blockReason: BlockReason?, safetyRatings: [SafetyRating]) {
+  public init(blockReason: BlockReason?, blockReasonMessage: String? = nil,
+              safetyRatings: [SafetyRating]) {
     self.blockReason = blockReason
+    self.blockReasonMessage = blockReasonMessage
     self.safetyRatings = safetyRatings
   }
 }
@@ -387,6 +392,7 @@ extension Citation: Decodable {
 extension PromptFeedback: Decodable {
   enum CodingKeys: CodingKey {
     case blockReason
+    case blockReasonMessage
     case safetyRatings
   }
 
@@ -396,6 +402,7 @@ extension PromptFeedback: Decodable {
       PromptFeedback.BlockReason.self,
       forKey: .blockReason
     )
+    blockReasonMessage = try container.decodeIfPresent(String.self, forKey: .blockReasonMessage)
     if let safetyRatings = try container.decodeIfPresent(
       [SafetyRating].self,
       forKey: .safetyRatings

FirebaseVertexAI/Tests/Unit/GenerativeModelTests.swift

@@ -619,6 +619,29 @@ final class GenerativeModelTests: XCTestCase {
       XCTFail("Should throw")
     } catch let GenerateContentError.promptBlocked(response) {
       XCTAssertNil(response.text)
+      let promptFeedback = try XCTUnwrap(response.promptFeedback)
+      XCTAssertEqual(promptFeedback.blockReason, PromptFeedback.BlockReason.safety)
+      XCTAssertNil(promptFeedback.blockReasonMessage)
+    } catch {
+      XCTFail("Should throw a promptBlocked")
+    }
+  }
+
+  func testGenerateContent_failure_promptBlockedSafetyWithMessage() async throws {
+    MockURLProtocol
+      .requestHandler = try httpRequestHandler(
+        forResource: "unary-failure-prompt-blocked-safety-with-message",
+        withExtension: "json"
+      )
+
+    do {
+      _ = try await model.generateContent(testPrompt)
+      XCTFail("Should throw")
+    } catch let GenerateContentError.promptBlocked(response) {
+      XCTAssertNil(response.text)
+      let promptFeedback = try XCTUnwrap(response.promptFeedback)
+      XCTAssertEqual(promptFeedback.blockReason, PromptFeedback.BlockReason.safety)
+      XCTAssertEqual(promptFeedback.blockReasonMessage, "Reasons")
     } catch {
       XCTFail("Should throw a promptBlocked")
     }
@@ -909,7 +932,31 @@ final class GenerativeModelTests: XCTestCase {
         XCTFail("Content shouldn't be shown, this shouldn't happen.")
       }
     } catch let GenerateContentError.promptBlocked(response) {
-      XCTAssertEqual(response.promptFeedback?.blockReason, .safety)
+      let promptFeedback = try XCTUnwrap(response.promptFeedback)
+      XCTAssertEqual(promptFeedback.blockReason, .safety)
+      XCTAssertNil(promptFeedback.blockReasonMessage)
+      return
+    }
+
+    XCTFail("Should have caught an error.")
+  }
+
+  func testGenerateContentStream_failurePromptBlockedSafetyWithMessage() async throws {
+    MockURLProtocol
+      .requestHandler = try httpRequestHandler(
+        forResource: "streaming-failure-prompt-blocked-safety-with-message",
+        withExtension: "txt"
+      )
+
+    do {
+      let stream = try model.generateContentStream("Hi")
+      for try await _ in stream {
+        XCTFail("Content shouldn't be shown, this shouldn't happen.")
+      }
+    } catch let GenerateContentError.promptBlocked(response) {
+      let promptFeedback = try XCTUnwrap(response.promptFeedback)
+      XCTAssertEqual(promptFeedback.blockReason, .safety)
+      XCTAssertEqual(promptFeedback.blockReasonMessage, "Reasons")
       return
     }