Repository: explodinggradients/ragas
Issue: NameError when evaluating the llamaindex query engine
Root cause: Validation Gap

[ ] I have checked the [documentation](https://docs.ragas.io/) and related resources and couldn't resolve my bug.

**Describe the bug**
When evaluating the llamaindex query engine, I get a `NameError`: name 'EvaluationResult' is not defined.

Ragas version: 0.3.5
Python version: 3.13.3

**Code to Reproduce**
https://docs.ragas.io/en/stable/howtos/integrations/_llamaindex/

**Error trace**
```
/Users/admin/Documents/Projects/AgenticSystem/.venv/lib/python3.13/site-packages/pydantic/_internal/_generate_schema.py:2225: UnsupportedFieldAttributeWarning: The 'validate_default' attribute with value True was provided to the `Field()` function, which has no effect in the context it was used. 'validate_default' is field-specific metadata, and can only be attached to a model field using `Annotated` metadata or by assignment. This may have happened because an `Annotated` type alias using the `type` statement was used, or if the `Field()` function was attached to a single member of a union type.
  warnings.warn(
Running Query Engine: 100%|███████████████████████████████████████████████████| 5/5 [00:05<00:00,  1.10s/it]
Evaluating:   0%|                                                                    | 0/20 [00:00<?, ?it/s]n values greater than 1 not support for LlamaIndex LLMs
n values greater than 1 not support for LlamaIndex LLMs
n values greater than 1 not support for LlamaIndex LLMs
n values greater than 1 not support for LlamaIndex LLMs
Exception raised in Job[9]: IndexError(list index out of range)
Exception raised in Job[13]: IndexError(list index out of range)
n values greater than 1 not support for LlamaIndex LLMs
Evaluating:   5%|███                                                         | 1/20 [00:04<01:24,  4.46s/it]Exception raised in Job[5]: IndexError(list index out of range)
Evaluating:  15%|█████████                                                   | 3/20 [00:12<01:08,  4.05s/it]Exception raised in Job[1]: IndexError(list index out of range)
Evaluating:  40%|████████████████████████                                    | 8/20 [00:13<00:15,  1.32s/it]Exception raised in Job[17]: IndexError(list index out of range)
Evaluating: 100%|███████████████████████████████████████████████████████████| 20/20 [00:26<00:00,  1.31s/it]
Traceback (most recent call last):
  File "/Users/admin/Documents/Projects/AgenticSystem/src/evaluation/ragas_test.py", line 99, in <module>
    result = evaluate(
        query_engine=query_engine,
    ...<2 lines>...
        run_config=RunConfig(timeout=6000),
    )
  File "/Users/admin/Documents/Projects/AgenticSystem/.venv/lib/python3.13/site-packages/ragas/integrations/llama_index.py", line 107, in evaluate
    return t.cast(EvaluationResult, results)
                  ^^^^^^^^^^^^^^^^
NameError: name 'EvaluationResult' is not defined. Did you mean: 'EvaluationDataset'?
```

**Expected behavior**
Successfully execute the evaluation process.

**Another question**
In addition, I see some warnings and exceptions in the program output. Will this affect the evaluation results?


hey @hzhaoy the PR should fix it - can you check if you get a chance? would help close it faster 🙂 

> hey [@hzhaoy](https://github.com/hzhaoy) the PR should fix it - can you check if you get a chance? would help close it faster 🙂

LGTM!!!