Handle notification errors (#31868)

packages/flutter_driver/lib/src/driver/driver.dart

@@ -934,9 +934,18 @@ void restoreVmServiceConnectFunction() {
 }
 
 void _unhandledJsonRpcError(dynamic error, dynamic stack) {
+  if (error is rpc.RpcException) {
+    final rpc.RpcException rpcException = error;
+    if (rpcException.data != null && rpcException.data['id'] == null) {
+      // This can happen, e.g., if a client tries to call us before methods have
+      // been registered, but the client doesn't care for a response.
+      _log.trace('RPC client sent a notification that resulted in an error:\n$error');
+      return;
+    }
+    assert(false, 'json_rpc_2 failed to send an exception back to the client.');
+  }
   _log.trace('Unhandled RPC error:\n$error\n$stack');
-  // TODO(dnfield): https://github.com/flutter/flutter/issues/31813
-  // assert(false);
+  assert(false);
 }
 
 /// Waits for a real Dart VM service to become available, then connects using

packages/flutter_tools/lib/src/vmservice.dart

@@ -237,6 +237,16 @@ class VMService {
   }
 
   static void _unhandledError(dynamic error, dynamic stack) {
+    if (error is rpc.RpcException) {
+      final rpc.RpcException rpcException = error;
+      if (rpcException.data != null && rpcException.data['id'] == null) {
+        // This can happen, e.g., if a client tries to call us before methods have
+        // been registered, but the client doesn't care for a response.
+        logger.printTrace('RPC client sent a notification that resulted in an error:\n$error');
+        return;
+      }
+      assert(false, 'json_rpc_2 failed to send an exception back to the client.');
+    }
     logger.printTrace('Error in internal implementation of JSON RPC.\n$error\n$stack');
     assert(false);
   }

packages/fuchsia_remote_debug_protocol/lib/src/dart/dart_vm.dart

@@ -33,6 +33,14 @@ RpcPeerConnectionFunction fuchsiaVmServiceConnectionFunction = _waitAndConnect;
 
 
 void _unhandledJsonRpcError(dynamic error, dynamic stack) {
+  if (error is json_rpc.RpcException) {
+    final json_rpc.RpcException rpcException = error;
+    if (rpcException.data != null && rpcException.data['id'] == null) {
+      // This can happen, e.g., if a client tries to call us before methods have
+      // been registered, but the client doesn't care for a response.
+      return;
+    }
+  }
   _log.fine('Error in internalimplementation of JSON RPC.\n$error\n$stack');
 }