[AI] Fix crash caused by unhandled goAway server message in LiveSession #7649

Kick-snare · 2026-01-16T13:34:44Z

Description

This PR adds support for the goAway server message type in LiveSession to prevent crashes when the server initiates a disconnect. Previously, when the server sent a goAway message, the app would crash with a SerializationException because the message type was not recognized by LiveServerMessageSerializer.

Changes

1. Add LiveServerGoAway message type

Added LiveServerGoAway class to represent server-initiated disconnection
Includes timeLeft: String? field containing duration in protobuf format (e.g., "57s", "1.5s")
Added parseTimeLeft() helper method to convert timeLeft string to kotlin.time.Duration
Registered goAway message in LiveServerMessageSerializer

2. Robust Handling & API Update

Crash Prevention: Added CoroutineExceptionHandler to networkScope and audioScope to act as a safety net against unhandled exceptions.
Graceful Shutdown: Implemented logic in processModelResponses() to recognize GoAway signals and automatically close the session, preventing zombie connections or further crashes.
Public API: Added goAwayHandler to LiveAudioConversationConfig.
- Rationale: While internal handling prevents the crash, apps often need to inform the user that the session ended due to server maintenance or timeouts. This handler exposes the timeLeft information to the application layer.

3. Comprehensive unit tests

Created LiveServerMessageTests.kt with 18 test cases covering:
- Duration parsing (integer seconds, fractional seconds, edge cases)
- LiveServerGoAway deserialization (with/without timeLeft)
- Polymorphic serializer recognition
Added serialization schema test in SerializationTests.kt
All 164 tests pass

Usage Example

Apps can now handle server disconnections gracefully using the goAwayHandler:

val config = LiveAudioConversationConfig.Builder()
  .setGoAwayHandler { goAway ->
    val timeLeft = goAway.parseTimeLeft()
    Log.i(TAG, "Server disconnecting in ${timeLeft?.inWholeSeconds} seconds")
    // Clean up resources, show UI notification, etc.
  }
  .build()

liveGenerativeModel.startAudioConversation(config)

Testing

✅ All 164 unit tests pass
✅ Tested with real app and confirmed graceful handling of goAway messages (Published to local Maven)
✅ Spotless formatting applied

Related Issues

Android SDK: SerializationException on "goAway" message in LiveSession #7648
Flutter SDK: 🚀 [firebase_ai] Support GoAway message in LiveGenerativeModel flutterfire#17836

Servers send goAway messages to gracefully disconnect sessions. The timeLeft field uses protobuf Duration string format.

Add exception handling and goAwayHandler support: - Add CoroutineExceptionHandler to prevent crashes - Handle LiveServerGoAway in processModelResponses - Add goAwayHandler to LiveAudioConversationConfig

Add unit tests for LiveServerGoAway message handling: - Duration parsing tests (protobuf format) - Deserialization tests - Serialization schema test

gemini-code-assist · 2026-01-16T13:34:48Z

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google-cla · 2026-01-16T13:34:48Z

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emilypgoogle

Hi! Thanks for the PR, I've left some comments about changes we'd like to see and open questions for the contents and implementation choices made. Overall, once these are addressed, this general implementation seems well done to merge.

emilypgoogle · 2026-01-26T19:06:20Z

firebase-ai/src/main/kotlin/com/google/firebase/ai/type/LiveServerMessage.kt

+ * convert this to a [kotlin.time.Duration].
+ */
+@PublicPreviewAPI
+public class LiveServerGoAway(public val timeLeft: String?) : LiveServerMessage {


The SDK should convert this string into a public facing duration object and not expose the String.

emilypgoogle · 2026-01-26T19:06:41Z

firebase-ai/src/main/kotlin/com/google/firebase/ai/type/LiveServerMessage.kt

+   *
+   * @return The parsed duration, or null if [timeLeft] is null or cannot be parsed.
+   */
+  public fun parseTimeLeft(): kotlin.time.Duration? {


Re the previous comment, this method should be removed and called implicitly on toPublic

emilypgoogle · 2026-01-26T19:08:42Z

firebase-ai/src/main/kotlin/com/google/firebase/ai/type/LiveServerMessage.kt

+
+    // Remove 's' suffix and parse as double
+    val secondsStr = trimmed.dropLast(1)
+    val seconds = secondsStr.toDoubleOrNull() ?: return null


Could be rewritten as
secondsStr.toDoubleOrNull()?.seconds removing the lines below

emilypgoogle · 2026-01-26T19:09:19Z

firebase-ai/src/main/kotlin/com/google/firebase/ai/type/LiveServerMessage.kt

+    val seconds = secondsStr.toDoubleOrNull() ?: return null
+
+    seconds.seconds
+  } catch (e: Exception) {


What could be throwing an exception here? Is there a more scoped type possible, or is this vestigial?

emilypgoogle · 2026-01-26T19:10:31Z

firebase-ai/src/main/kotlin/com/google/firebase/ai/type/LiveSession.kt

+   *
+   * Logs the exception and attempts to clean up resources to prevent app crashes.
+   */
+  private val exceptionHandler = CoroutineExceptionHandler { _, throwable ->


Is this necessary for this PR? Ideally PRs should be well scoped.

emilypgoogle · 2026-01-26T19:11:38Z

firebase-ai/src/main/kotlin/com/google/firebase/ai/type/LiveSession.kt

+                  )
+                } catch (e: SerializationException) {
+                  Log.w(TAG, "Failed to deserialize server message: ${e.message}")
+                  null // Skip unknown messages instead of crashing


This is a notable behavior change, is avoiding crashes and skipping server messages actually the ideal behavior?

Kick-snare added 3 commits January 16, 2026 21:56

[AI] Add LiveServerGoAway message type

7c421f5

Servers send goAway messages to gracefully disconnect sessions. The timeLeft field uses protobuf Duration string format.

[AI] Handle goAway in LiveSession and add goAwayHandler

5536de9

Add exception handling and goAwayHandler support: - Add CoroutineExceptionHandler to prevent crashes - Handle LiveServerGoAway in processModelResponses - Add goAwayHandler to LiveAudioConversationConfig

[AI] Add tests for LiveServerGoAway

e0abffa

Add unit tests for LiveServerGoAway message handling: - Duration parsing tests (protobuf format) - Deserialization tests - Serialization schema test

Kick-snare mentioned this pull request Jan 16, 2026

SerializationException on "goAway" message in LiveSession #7648

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emilypgoogle requested changes Jan 26, 2026

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[AI] Fix crash caused by unhandled goAway server message in LiveSession #7649

[AI] Fix crash caused by unhandled goAway server message in LiveSession #7649

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[AI] Fix crash caused by unhandled goAway server message in LiveSession #7649

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Kick-snare commented Jan 16, 2026

Description

Changes

1. Add LiveServerGoAway message type

2. Robust Handling & API Update

3. Comprehensive unit tests

Usage Example

Testing

Related Issues

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