ollama-python: enable passing messages with "control" role to enable granite3.2 thinking control functionality

[rylativity]

Ollama's python client currently only permits messages with roles of either 'user', 'assistant', 'system', or 'tool'.

As described here - ollama/ollama#8955 (comment) - this prevents sending messages with the "control" role, which was introduced by IBM's granite3.2 to enable turning the "thinking" functionality on and off as needed.

This pull request adds "control" to the list of valid values for a message's "role" field/attribute so that these messages can be passed through to ollama.

Note: ollama server already handles messages with this role appropriately, but the python client currently does not allow sending them to ollama server. This resolves the issue in the python client.

[lemassykoi]

thanks, but I did your modification on my computer, and enabled full traceback.
The problem is from langchain_core/messages/utils.py at func _create_message_from_message_type

[rylativity]

This PR addresses the original issue you reported within the ollama-python client. I was able to reproduce your original issue with the original code that you shared, and it does not use langchain.

The new traceback you shared above is different and is a separate error coming from langchain-core, which is a different project/codebase.

Will you please share the code or command that you ran that resulted in the langchain error above? I'm happy to take a look and try to open a PR for langchain-core as well.

[gabe-l-hart]

One quick addition if we're going to go the route of expanding the set of literals, we should consider including "document" as well.

[lemassykoi]

This PR addresses the original issue you reported within the ollama-python client. I was able to reproduce your original issue with the original code that you shared, and it does not use langchain.

The new traceback you shared above is different and is a separate error coming from langchain-core, which is a different project/codebase.

Will you please share the code or command that you ran that resulted in the langchain error above? I'm happy to take a look and try to open a PR for langchain-core as well.

Thanks, this is my orighinal post with original code :

langchain-ai/langchain#30122 (comment)