[Bug]: REST get_task does not send historyLength=0, causing full history to return #479
Description
What happened?
Environment
- a2a-python: v0.3.7
- Python: 3.13
- Transport: REST (RestTransport)
- Server: FastAPI + Uvicorn（A2A REST backend）
Expected behavior
history_length=0 should result in ?historyLength=0 being sent, yielding zero history items (or the field being omitted).
Actual behavior
No historyLength parameter is sent when 0 is provided, leading to full history being returned.
Steps to Reproduce
task = await client.get_task(TaskQueryParams(id=task_id, history_length=0))
It looks like request.history_length is evaluated directly here, so 0 is treated as falsy:
a2a-python/src/a2a/client/transports/rest.py
Lines 214 to 220 in 4a4b4a9
Relevant log output
Code of Conduct
- I agree to follow this project's Code of Conduct