Raise an error if an LLM doesnt return a response (#1548)

src/crewai/agents/crew_agent_executor.py

@@ -117,6 +117,15 @@ class CrewAgentExecutor(CrewAgentExecutorMixin):
                         callbacks=self.callbacks,
                     )
 
+                    if answer is None or answer == "":
+                        self._printer.print(
+                            content="Received None or empty response from LLM call.",
+                            color="red",
+                        )
+                        raise ValueError(
+                            "Invalid response from LLM call - None or empty."
+                        )
+
                     if not self.use_stop_words:
                         try:
                             self._format_answer(answer)

src/crewai/llm.py

@@ -1,7 +1,10 @@
+import io
+import logging
+import sys
+import warnings
 from contextlib import contextmanager
 from typing import Any, Dict, List, Optional, Union
-import logging
+
-import warnings
 import litellm
 from litellm import get_supported_openai_params
 
@@ -9,9 +12,6 @@ from crewai.utilities.exceptions.context_window_exceeding_exception import (
     LLMContextLengthExceededException,
 )
 
-import sys
-import io
-
 
 class FilteredStream(io.StringIO):
     def write(self, s):