fix gemini live tool execution interrupted by generation_complete event (#4699)

Author: longcw

livekit-plugins/livekit-plugins-google/livekit/plugins/google/realtime/realtime_api.py

@@ -1354,11 +1354,16 @@ def _is_new_generation(self, resp: types.LiveServerMessage) -> bool:
 
         if (sc := resp.server_content) and (
             sc.model_turn
-            or (sc.output_transcription and sc.output_transcription is not None)
-            or (sc.input_transcription and sc.input_transcription is not None)
-            or (sc.generation_complete is not None)
-            or (sc.turn_complete is not None)
+            or (
+                sc.output_transcription and sc.output_transcription and sc.output_transcription.text
+            )
+            or (sc.input_transcription and sc.input_transcription and sc.input_transcription.text)
+            # or (sc.generation_complete is not None)
+            # or (sc.turn_complete is not None)
         ):
+            # Some Gemini models send a `generation_complete` event after tool calls, but others do not.
+            # We mark the generation as done after a tool call and need to ignore any empty transcriptions or generation_complete events.
+            # This prevents new empty generations from starting and interrupting tool execution.
             return True
 
         return False