langchain

8bebc920 - Add improved sources splitting in BaseQAWithSourcesChain (#8716)

Add improved sources splitting in BaseQAWithSourcesChain (#8716) ## Type: Improvement --- ## Description: Running QAWithSourcesChain sometimes raises ValueError as mentioned in issue #7184: ``` ValueError: too many values to unpack (expected 2) Traceback: response = qa({"question": pregunta}, return_only_outputs=True) File "C:\Anaconda3\envs\iagen_3_10\lib\site-packages\langchain\chains\base.py", line 166, in __call__ raise e File "C:\Anaconda3\envs\iagen_3_10\lib\site-packages\langchain\chains\base.py", line 160, in __call__ self._call(inputs, run_manager=run_manager) File "C:\Anaconda3\envs\iagen_3_10\lib\site-packages\langchain\chains\qa_with_sources\base.py", line 132, in _call answer, sources = re.split(r"SOURCES:\s", answer) ``` This is due to LLM model generating subsequent question, answer and sources, that is complement in a similar form as below: ``` <final_answer> SOURCES: <sources> QUESTION: <new_or_repeated_question> FINAL ANSWER: <new_or_repeated_final_answer> SOURCES: <new_or_repeated_sources> ``` It leads the following line ``` re.split(r"SOURCES:\s", answer) ``` to return more than 2 elements and result in ValueError. The simple fix is to split also with "QUESTION:\s" and take the first two elements: ``` answer, sources = re.split(r"SOURCES:\s|QUESTION:\s", answer)[:2] ``` Sometimes LLM might also generate some other texts, like alternative answers in a form: ``` <final_answer_1> SOURCES: <sources> <final_answer_2> SOURCES: <sources> <final_answer_3> SOURCES: <sources> ``` In such cases it is the best to split previously obtained sources with new line: ``` sources = re.split(r"\n", sources.lstrip())[0] ``` --- ## Issue: Resolves #7184 --- ## Maintainer: @baskaryan