[Sonica-B]

Description

JsonRpcTransport turned every response body into a json-rpc JSONRPC20Response (JSONRPC20Response(**response_data) in the nine unary methods, JSONRPC20Response.from_json for SSE events). That package validates the envelope with its own exceptions, so a body that is not a JSON-RPC 2.0 response object reached the caller as a raw TypeError, ValueError or json.JSONDecodeError instead of an A2AClientError:

Response body	Before	After
a list, or a string (e.g. from a proxy)	TypeError: ... argument after ** must be a mapping	A2AClientError
an object with neither result nor error	ValueError: Either result or error should be used	A2AClientError
"error": "boom"	TypeError: ... argument after ** must be a mapping	A2AClientError
error object with an extra member, e.g. {"code": -32001, "message": "...", "reason": "x"}	TypeError: JSONRPCError.__init__() got an unexpected keyword argument 'reason'	TaskNotFoundError
error object without message, e.g. {"code": -32001}	ValueError: Error message should be string	TaskNotFoundError
SSE data: that is not JSON	json.JSONDecodeError (raised in the consumer loop, outside handle_http_exceptions)	A2AClientError
event: error whose error object has an extra member	TypeError	TaskNotFoundError

The last two error-object rows matter most: the server sent a valid A2A error code, and _create_jsonrpc_error already handles a missing message (error_dict.get('message', str(error_dict))), but the json-rpc validation failed before that code ran. It is also the error-object counterpart of the spec 5.7 leniency added for results in #1354.

Change, all in src/a2a/client/transports/jsonrpc.py:

• New _check_jsonrpc_response: an error object raises the mapped A2A error through the existing _create_jsonrpc_error; a non-object body, a non-object error, or a body with neither result nor error raises A2AClientError. A falsy error next to a result is still treated as success, as before.
• _send_request and the SSE loop call it, so the unary methods read response_data['result'] and no longer need their own error checks. _handle_sse_error parses with json.loads and keeps its SSE stream error: ... fallback.
• JSONRPC20Response is no longer used on the client (requests still use JSONRPC20Request). Well-formed success and error responses behave as before; the existing tests pass unchanged.

Tests: TestMalformedJsonRpcResponses in tests/client/transports/test_jsonrpc_client.py, 11 cases (unary invalid envelopes, non-standard error objects, streaming data: and event: error, plus a guard that delete_task_push_notification_config still raises on an error response). 10 of them fail on main with the exceptions in the table and pass with the change.

The v0.3 CompatJsonRpcTransport has the same JSONRPC20Response(**response_data) pattern (an error object with an extra member raises TypeError there too). I kept this PR to the 1.0 client and can send a fix(compat) follow-up.

Checks, run on Windows 11 with Python 3.10.19:

• bash ./scripts/lint.sh: ruff check, ruff format and ty pass (three existing unused type: ignore warnings in files this PR does not touch).

• uv run pytest tests/client/transports/test_jsonrpc_client.py: 51 passed.

• uv run pytest --ignore=tests/integration/cross_version --ignore=tests/integration/test_scenarios.py --cov=src: 2213 passed, 199 skipped, 3 xfailed; total coverage 93%. The 3 failures (test_samples_smoke.py, console encoding) and 4 setup errors (push_notifications e2e, Can't pickle local object under Windows spawn) fail the same way on main here. tests/integration/cross_version (uses os.killpg) and tests/integration/test_scenarios.py (hangs on Windows on main too; it only builds gRPC clients) were not run locally, so the Linux CI run is the check for those.

• Follow the CONTRIBUTING Guide.

• Make your Pull Request title in the https://www.conventionalcommits.org/ specification.

• Ensure the tests and linter pass

• Appropriate docs were updated (if necessary)

[github-actions]

🧪 Code Coverage (vs main)

⬇️ Download Full Report

	Base	PR	Delta
src/a2a/client/transports/jsonrpc.py	92.66%	95.51%	🟢 +2.86%
Total	93.03%	93.08%	🟢 +0.05%

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[Iwaniukooo11]

LGTM