Tongyi llm call error with model "qwen-long"

[niuguy]

Checked other resources

• I added a very descriptive title to this issue.
• I searched the LangChain documentation with the integrated search.
• I used the GitHub search to find a similar question and didn't find it.
• I am sure that this is a bug in LangChain rather than my code.
• The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

Example Code

from langchain_community.llms.tongyi import Tongyi
import os

tongyi = Tongyi(model="qwen-turbo", api_key=api_key)

response = tongyi.invoke("Who are you?")

print(response)

Error Message and Stack Trace (if applicable)

Traceback (most recent call last):
  File "/Users/feng/Work/my/tests/qwen/api_test.py", line 33, in <module>
    response = tongyi.invoke("Who are you?")
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/feng/Work/my/tests/qwen/.venv/lib/python3.12/site-packages/langchain_core/language_models/llms.py", line 390, in invoke
    self.generate_prompt(
  File "/Users/feng/Work/my/tests/qwen/.venv/lib/python3.12/site-packages/langchain_core/language_models/llms.py", line 755, in generate_prompt
    return self.generate(prompt_strings, stop=stop, callbacks=callbacks, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/feng/Work/my/tests/qwen/.venv/lib/python3.12/site-packages/langchain_core/language_models/llms.py", line 950, in generate
    output = self._generate_helper(
             ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/feng/Work/my/tests/qwen/.venv/lib/python3.12/site-packages/langchain_core/language_models/llms.py", line 792, in _generate_helper
    raise e
  File "/Users/feng/Work/my/tests/qwen/.venv/lib/python3.12/site-packages/langchain_core/language_models/llms.py", line 779, in _generate_helper
    self._generate(
  File "/Users/feng/Work/my/tests/qwen/.venv/lib/python3.12/site-packages/langchain_community/llms/tongyi.py", line 327, in _generate
    [Generation(**self._generation_from_qwen_resp(completion))]
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/feng/Work/my/tests/qwen/.venv/lib/python3.12/site-packages/langchain_core/load/serializable.py", line 125, in __init__
    super().__init__(*args, **kwargs)
  File "/Users/feng/Work/my/tests/qwen/.venv/lib/python3.12/site-packages/pydantic/main.py", line 214, in __init__
    validated_self = self.__pydantic_validator__.validate_python(data, self_instance=self)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
pydantic_core._pydantic_core.ValidationError: 1 validation error for Generation
text
  Input should be a valid string [type=string_type, input_value=None, input_type=NoneType]
    For further information visit https://errors.pydantic.dev/2.10/v/string_type

Description

I tried other models listed here [qwen-max, qwen-turbo, qwen-plus] which are all working fine

I debugged and stepped into the source code and found that this line should be the root cause as for "qwen-long" the api returns "choices" instead of "text" which results in a Nonetype

you can debug and replicate it like

from langchain_community.llms.tongyi import Tongyi
import os

original_generate = Tongyi._generate

def debug_generate(self, prompts, stop=None, run_manager=None, **kwargs):
    breakpoint()  
    return original_generate(self, prompts, stop, run_manager, **kwargs)

# Patch the method
Tongyi._generate = debug_generate
api_key = os.getenv("DASHSCOPE_API_KEY")

tongyi = Tongyi(model="qwen-turbo", api_key=api_key)

response = tongyi.invoke("Who are you?")

print(response)

This issue could potentially be resolved by checking both resp["output"]["text"] and resp["output"]["choices"] for the response. However, it’s unclear if this inconsistency stems from the Tongyi server. The module’s maintainer might be able to provide clarification.

System Info

System Information
------------------
> OS:  Darwin
> OS Version:  Darwin Kernel Version 24.1.0: Thu Oct 10 21:03:15 PDT 2024; root:xnu-11215.41.3~2/RELEASE_ARM64_T6000
> Python Version:  3.12.5 (main, Aug 14 2024, 04:32:18) [Clang 18.1.8 ]

Package Information
-------------------
> langchain_core: 0.3.28
> langchain: 0.3.13
> langchain_community: 0.3.13
> langsmith: 0.2.6
> langchain_text_splitters: 0.3.4

Optional packages not installed
-------------------------------
> langserve

Other Dependencies
------------------
> aiohttp: 3.11.11
> async-timeout: Installed. No version info available.
> dataclasses-json: 0.6.7
> httpx: 0.28.1
> httpx-sse: 0.4.0
> jsonpatch: 1.33
> langsmith-pyo3: Installed. No version info available.
> numpy: 2.2.1
> orjson: 3.10.12
> packaging: 24.2
> pydantic: 2.10.4
> pydantic-settings: 2.7.0
> PyYAML: 6.0.2
> requests: 2.32.3
> requests-toolbelt: 1.0.0
> SQLAlchemy: 2.0.36
> tenacity: 9.0.0
> typing-extensions: 4.12.2
> zstandard: Installed. No version info available.