Always invoke binary reply callback when message handler throws#20
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If the FlutterBinaryMessageHandler throws, the reply callback was never called, leaving the Flutter engine's MallocMapping-owned message buffer permanently retained. This matches the pattern described in flutter/flutter#159363 where every unacknowledged platform message leaks ~96–192 bytes. Fix both FlutterPlatformMessenger (Darwin/iOS/Android) and FlutterDesktopMessenger (Linux/eLinux) to always call the reply with nil on error, so the engine can release the allocation regardless of handler outcome. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Summary
FlutterPlatformMessenger.setMessageHandler(Darwin/iOS/Android) andFlutterDesktopMessenger.setMessageHandler(Linux/eLinux) both spawn aTaskto call the user-suppliedFlutterBinaryMessageHandler. If that handler throws, the task exits without ever calling the reply callback (FlutterBinaryReply/sendResponse).MallocMapping-owned message buffer until the reply callback is invoked. When it is never called, the buffer leaks permanently — one per unacknowledged message.oca/property_eventandoca/set_propertyplatform channels in InfernoUI (PADL/inferno_ui#52): 90 leaks (~3.7 KB) after 22 seconds of normal operation, growing without bound.Fix
Wrap the
try await handler(message)call in ado/catchin both messenger implementations and callcallback(nil)/sendResponse(..., response: nil)in the catch block, ensuring the reply is always delivered regardless of handler outcome.Test plan
leaks <pid>after 2+ hours of operation; confirm zero leaks attributed tooca/property_eventoroca/set_property🤖 Generated with Claude Code