flutter runtime_error ai_generated true

Unhandled exception: IsolateSpawnException: Failed to send message: SendPort is already closed

ID: flutter/isolate-send-port-closed

Also available as: JSON · Markdown · 中文
80%Fix Rate
83%Confidence
1Evidence
2024-01-05First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
Flutter 3.13.0 active — — —
Dart 3.1.0 active — — —

Root Cause

An attempt was made to send a message via a SendPort that has been closed, typically because the receiving isolate has terminated or the port was disposed.

generic

中文

尝试通过已关闭的 SendPort 发送消息，通常是因为接收隔离已终止或端口已被释放。

Official Documentation

https://api.dart.dev/stable/3.1.0/dart-isolate/Isolate-class.html

Workarounds

  1. 85% success Check if the receiving isolate is still alive before sending. Use a shared flag or a ping mechanism: if (receivePort.isClosed) { await spawnIsolate(); } then send. 
    Check if the receiving isolate is still alive before sending. Use a shared flag or a ping mechanism: if (receivePort.isClosed) { await spawnIsolate(); } then send.
  2. 80% success Implement a reconnection strategy: when the error occurs, close the old SendPort, spawn a new isolate, and recreate the port pair. Example: isolate = await Isolate.spawn(entryPoint, receivePort.sendPort); sendPort = isolate.controlPort; 
    Implement a reconnection strategy: when the error occurs, close the old SendPort, spawn a new isolate, and recreate the port pair. Example: isolate = await Isolate.spawn(entryPoint, receivePort.sendPort); sendPort = isolate.controlPort;
  3. 75% success Use a dedicated communication manager that monitors isolate lifecycle and automatically re-establishes ports on termination. 
    Use a dedicated communication manager that monitors isolate lifecycle and automatically re-establishes ports on termination.

中文步骤

  1. Check if the receiving isolate is still alive before sending. Use a shared flag or a ping mechanism: if (receivePort.isClosed) { await spawnIsolate(); } then send.
  2. Implement a reconnection strategy: when the error occurs, close the old SendPort, spawn a new isolate, and recreate the port pair. Example: isolate = await Isolate.spawn(entryPoint, receivePort.sendPort); sendPort = isolate.controlPort;
  3. Use a dedicated communication manager that monitors isolate lifecycle and automatically re-establishes ports on termination.

Dead Ends

Common approaches that don't work:

  1. Increase the size of the isolate's message queue. 95% fail

    The error is not about queue capacity but about the port being closed; queue size does not affect closed ports.

  2. Wrap the send call in a try-catch and ignore the error. 80% fail

    Ignoring the error leads to silent data loss; the root cause (port closure) remains unaddressed.