Fix bug with google model safety handling (#2066)

Author: dmontagu

pydantic_ai_slim/pydantic_ai/models/google.py

@@ -374,17 +374,18 @@ async def _build_content_and_config(
     def _process_response(self, response: GenerateContentResponse) -> ModelResponse:
         if not response.candidates or len(response.candidates) != 1:
             raise UnexpectedModelBehavior('Expected exactly one candidate in Gemini response')  # pragma: no cover
-        if response.candidates[0].content is None or response.candidates[0].content.parts is None:
-            if response.candidates[0].finish_reason == 'SAFETY':
+        candidate = response.candidates[0]
+        if candidate.content is None or candidate.content.parts is None:
+            if candidate.finish_reason == 'SAFETY':
                 raise UnexpectedModelBehavior('Safety settings triggered', str(response))
             else:
                 raise UnexpectedModelBehavior(
                     'Content field missing from Gemini response', str(response)
                 )  # pragma: no cover
-        parts = response.candidates[0].content.parts or []
+        parts = candidate.content.parts or []
         vendor_id = response.response_id or None
         vendor_details: dict[str, Any] | None = None
-        finish_reason = response.candidates[0].finish_reason
+        finish_reason = candidate.finish_reason
         if finish_reason:  # pragma: no branch
             vendor_details = {'finish_reason': finish_reason.value}
         usage = _metadata_as_usage(response)
@@ -526,8 +527,12 @@ async def _get_event_iterator(self) -> AsyncIterator[ModelResponseStreamEvent]:
 
             assert chunk.candidates is not None
             candidate = chunk.candidates[0]
-            if candidate.content is None:
-                raise UnexpectedModelBehavior('Streamed response has no content field')  # pragma: no cover
+            if candidate.content is None or candidate.content.parts is None:
+                if candidate.finish_reason == 'SAFETY':  # pragma: no cover
+                    raise UnexpectedModelBehavior('Safety settings triggered', str(chunk))
+                else:  # pragma: no cover
+                    raise UnexpectedModelBehavior('Content field missing from streaming Gemini response', str(chunk))
+
             assert candidate.content.parts is not None
             for part in candidate.content.parts:
                 if part.text is not None: