Description

RestTransport.delete_task_push_notification_config goes through _execute_request, which always calls response.json(). The spec leaves the result to the server (3.1.10: "Confirmation of deletion (implementation-specific)"), and the SDKs answer differently:

• this SDK's server answers 200 with {};
• a2a-js answers 204 No Content (rest_handler.ts);
• a2a-go answers 200 with no body (handleDeleteTaskPushConfig).

Against a2a-js or a2a-go servers, the config is deleted, but the Python client then raises A2AClientError: JSON Decode Error. A caller that retries or reports the failure is acting on a delete that succeeded.

The delete now sends its request, checks the status, and does not read the body. Error responses still go through _handle_http_error, so a 404 with TASK_NOT_FOUND still raises TaskNotFoundError. send_http_request and the JSON-RPC transport are unchanged.

The repro at the end of this description answers the delete the way each server does. On main (2cc1dd5):

a2a-python 200 b'{}' -> ok
a2a-js     204 b''   -> A2AClientError: JSON Decode Error: Expecting value: line 1 column 1 (char 0)
a2a-go     200 b''   -> A2AClientError: JSON Decode Error: Expecting value: line 1 column 1 (char 0)

On this branch, all three print ok.

$ pytest tests/client/transports/test_rest_client.py   # src change reverted
FAILED ...::TestTaskCallback::test_delete_task_push_notification_config_ignores_body[no_content]
FAILED ...::TestTaskCallback::test_delete_task_push_notification_config_ignores_body[empty_200]
2 failed, 44 passed
$ pytest --ignore=tests/integration/cross_version   # this branch, Python 3.10, locked deps
2560 passed, 207 skipped, 4 xfailed, 1 xpassed
$ pytest --cov=src
src/a2a/client/transports/rest.py   87%   (the new lines are covered)
TOTAL   94%

The new tests also cover a mapped error and a closed client on this path. I left the cross-version tests out because their servers don't start within the 3 s timeout on my machine; the same happens on main. ruff check, ruff format and ty check pass. ty prints only the three existing unused type: ignore warnings.

#1439 touches send_http_request and the transport type hints. This change stays inside delete_task_push_notification_config to keep out of its way, apart from one added import. #1436 percent-encodes the ids in this method's path, so whichever of the two lands second has a one-line conflict there; I'll rebase this one if #1436 goes first.

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• Ensure the tests and linter pass (Run bash scripts/format.sh from the repository root to format)
• Appropriate docs were updated (if necessary)

No issue exists, since the new tests reproduce it.

import asyncio

import httpx

from a2a.client.transports.rest import RestTransport
from a2a.types.a2a_pb2 import AgentCard, DeleteTaskPushNotificationConfigRequest

# How each SDK's server confirms DELETE /tasks/{id}/pushNotificationConfigs/{configId}.
SERVERS = {'a2a-python': (200, b'{}'), 'a2a-js': (204, b''), 'a2a-go': (200, b'')}


async def main() -> None:
    for name, (status, body) in SERVERS.items():
        transport = httpx.MockTransport(lambda r, s=status, b=body: httpx.Response(s, content=b))
        async with httpx.AsyncClient(transport=transport) as http:
            client = RestTransport(http, AgentCard(), 'http://agent.example')
            try:
                await client.delete_task_push_notification_config(
                    DeleteTaskPushNotificationConfigRequest(task_id='t1', id='cfg1')
                )
                print(f'{name:10} {status} {body!r:5} -> ok')
            except Exception as e:
                print(f'{name:10} {status} {body!r:5} -> {type(e).__name__}: {e}')


asyncio.run(main())

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