test: cover the rebuild that raises

The rebuild sits in its own try/except so a failing payload build cannot
stop the later callbacks, which is the rule main wrote around the primary
build. Nothing asserted that, and the except branch was the one part of
this change with no coverage: the test now makes the empty-response retry
raise and checks that the success callback still fires.

tests/unit/litellm_core_utils/test_litellm_logging_slo_fallback.py

@@ -132,3 +132,50 @@ async def test_streaming_slo_double_build_failure_is_logged(monkeypatch, caplog)
     assert logging_obj.model_call_details["standard_logging_object"] is None
     assert build_calls == [result, {}]
     assert "rebuild failed" in caplog.text
+
+
+@pytest.mark.asyncio
+async def test_streaming_slo_rebuild_raising_does_not_block_callbacks(monkeypatch, caplog):
+    """The rebuild is wrapped for the same reason main wraps the primary build:
+    a payload build must never stop the later callbacks from running. If the
+    empty-response retry raises, the success callback still fires."""
+    logging_obj = Logging(
+        model="claude-3-5-sonnet-20240620",
+        messages=[{"role": "user", "content": "hi"}],
+        stream=True,
+        call_type="anthropic_messages",
+        start_time=datetime.now(),
+        litellm_call_id="test-32019-raise",
+        function_id="test-32019-raise",
+    )
+    build_calls = []
+
+    def fake_build(self, init_response_obj, start_time, end_time):
+        build_calls.append(init_response_obj)
+        if init_response_obj == {}:
+            raise RuntimeError("rebuild blew up")
+        return None
+
+    called_back = []
+
+    async def async_success_callback(kwargs, completion_response, start_time, end_time):
+        called_back.append(completion_response)
+
+    monkeypatch.setattr(Logging, "_build_standard_logging_payload", fake_build)
+    monkeypatch.setattr(litellm, "_async_success_callback", [async_success_callback])
+    monkeypatch.setattr(litellm, "success_callback", [])
+
+    result = ModelResponse(model="claude-3-5-sonnet-20240620")
+
+    with caplog.at_level(logging.ERROR, logger="LiteLLM"):
+        await logging_obj.async_success_handler(
+            result,
+            start_time=datetime.now(),
+            end_time=datetime.now(),
+            cache_hit=False,
+        )
+
+    assert build_calls == [result, {}]
+    assert logging_obj.model_call_details["standard_logging_object"] is None
+    assert "Exception rebuilding the degraded standard logging payload" in caplog.text
+    assert len(called_back) == 1