Not using Tools in Langchain_Ollama causes: 'NoneType' object is not iterable

[bauerem]

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_ollama import ChatOllama

llm = ChatOllama(
model="llama3.1",
temperature=0,
disable_streaming=True
)

messages = [
(
"system",
"You are a helpful assistant that translates English to French. Translate the user sentence.",
),
("human", "I love programming."),
]
ai_msg = llm.invoke(messages)
print(ai_msg)

Error Message and Stack Trace (if applicable)

Traceback (most recent call last):
File "/home/user1/Repo/ollama-cloud/use4.py", line 16, in
ai_msg = llm.invoke(messages)
File "/home/user1/Repo/ollama-cloud/venv/lib/python3.10/site-packages/langchain_core/language_models/chat_models.py", line 286, in invoke
self.generate_prompt(
File "/home/user1/Repo/ollama-cloud/venv/lib/python3.10/site-packages/langchain_core/language_models/chat_models.py", line 786, in generate_prompt
return self.generate(prompt_messages, stop=stop, callbacks=callbacks, **kwargs)
File "/home/user1/Repo/ollama-cloud/venv/lib/python3.10/site-packages/langchain_core/language_models/chat_models.py", line 643, in generate
raise e
File "/home/user1/Repo/ollama-cloud/venv/lib/python3.10/site-packages/langchain_core/language_models/chat_models.py", line 633, in generate
self._generate_with_cache(
File "/home/user1/Repo/ollama-cloud/venv/lib/python3.10/site-packages/langchain_core/language_models/chat_models.py", line 851, in _generate_with_cache
result = self._generate(
File "/home/user1/Repo/ollama-cloud/venv/lib/python3.10/site-packages/langchain_ollama/chat_models.py", line 648, in _generate
final_chunk = self._chat_stream_with_aggregation(
File "/home/user1/Repo/ollama-cloud/venv/lib/python3.10/site-packages/langchain_ollama/chat_models.py", line 560, in _chat_stream_with_aggregation
tool_calls=_get_tool_calls_from_response(stream_resp),
File "/home/user1/Repo/ollama-cloud/venv/lib/python3.10/site-packages/langchain_ollama/chat_models.py", line 71, in _get_tool_calls_from_response
for tc in response["message"]["tool_calls"]:
TypeError: 'NoneType' object is not iterable

Description

Trying to simple get a chat response from ChatOllama.

System Info

System Information

OS: Linux
OS Version: #49~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Wed Nov 6 17:42:15 UTC 2
Python Version: 3.10.12 (main, Nov 6 2024, 20:22:13) [GCC 11.4.0]

Package Information

langchain_core: 0.3.20
langchain: 0.3.7
langchain_community: 0.3.7
langsmith: 0.1.144
langchain_ollama: 0.2.0
langchain_text_splitters: 0.3.2

Optional packages not installed

langserve

Other Dependencies

aiohttp: 3.11.7
async-timeout: 4.0.3
dataclasses-json: 0.6.7
httpx: 0.27.2
httpx-sse: 0.4.0
jsonpatch: 1.33
numpy: 1.26.4
ollama: 0.4.0
orjson: 3.10.11
packaging: 24.2
pydantic: 2.10.1
pydantic-settings: 2.6.1
PyYAML: 6.0.2
requests: 2.32.3
requests-toolbelt: 1.0.0
SQLAlchemy: 2.0.35
tenacity: 9.0.0
typing-extensions: 4.12.2

[Fernando7181]

we had another issue that was similar to this one, maybe try python response["message"]["tool_calls"] is not None and see if that works

[bauerem]

Yes, that is how I would also fix the bug in the langchain implementation

[Fernando7181]

Yes, that is how I would also fix the bug in the langchain implementation

did it work?

[keenborder786]

@bauerem please upgrade to latest version of langchain-ollama. It should fix the issue.

[espositodaniele]

Same error here:

Package Information

ollama 0.4.1
langchain 0.3.8
langchain-community 0.3.8
langchain-core 0.3.21
langchain-ollama 0.2.0

Code example

from langchain_ollama import ChatOllama

model = ChatOllama(model="llama3.2", temperature=0)
model.invoke("Chi è il presidente degli Stati Uniti?")

Error

TypeError Traceback (most recent call last)
Cell In[34], line 4
1 from langchain_ollama import ChatOllama
3 model = ChatOllama(model="llama3.2", temperature=0)
----> 4 model.invoke("Chi è il presidente degli Stati Uniti?")

File ~/aidev/pdf-rag/.venv/lib/python3.13/site-packages/langchain_core/language_models/chat_models.py:286, in BaseChatModel.invoke(self, input, config, stop, **kwargs)
275 def invoke(
276 self,
277 input: LanguageModelInput,
(...)
281 **kwargs: Any,
282 ) -> BaseMessage:
283 config = ensure_config(config)
284 return cast(
285 ChatGeneration,
--> 286 self.generate_prompt(
287 [self._convert_input(input)],
288 stop=stop,
289 callbacks=config.get("callbacks"),
290 tags=config.get("tags"),
291 metadata=config.get("metadata"),
292 run_name=config.get("run_name"),
293 run_id=config.pop("run_id", None),
...
76 )
77 )
78 return tool_calls

TypeError: 'NoneType' object is not iterable

[nourishnew]

@keenborder786 Latest version doesn't seem to have the None check.

[keenborder786]

@nourishnew yeap you are correct I have fixed it it in the PR. Hopefully in the next release it will be fixed.