)

# Description

`REST03Adapter` mounts `GET`/`POST
/v1/tasks/{id}/pushNotificationConfigs` and `GET
/v1/tasks/{id}/pushNotificationConfigs/{push_id}`, but no `DELETE`. The
v0.3 binding defines `DELETE
/v1/tasks/{id}/pushNotificationConfigs/{configId}` (spec section 3.5.6,
and the `google.api.http` option on `DeleteTaskPushNotificationConfig`
in `a2a_v0_3.proto`), and the v0.3 JSON-RPC and gRPC adapters already
serve the call.

Without the route the request falls through to the v1.0 `/{tenant}`
mount with tenant `v1`, so a v0.3 client gets a 400 with reason
`VERSION_NOT_SUPPORTED` ("A2A version '0.3' is not supported by this
handler. Expected version '1.0'.").

To reproduce on main: serve a `DefaultRequestHandler` through
`create_rest_routes(..., enable_v0_3_compat=True)`, create a push config
over v0.3 REST, then send `DELETE
/v1/tasks/{task_id}/pushNotificationConfigs/{config_id}`. It returns
400. The same delete over v0.3 JSON-RPC
(`tasks/pushNotificationConfig/delete`) and gRPC
(`DeleteTaskPushNotificationConfig`) succeeds.

This change adds `REST03Handler.delete_push_notification`, which builds
a v0.3 `DeleteTaskPushNotificationConfigRequest` from the path and calls
the v1.0 handler through `RequestHandler03`, and mounts it. It returns
`{}`, the JSON form of `google.protobuf.Empty`, as the v1.0 REST
dispatcher does.

`CompatRestTransport.delete_task_push_notification_config` raised
`NotImplementedError`, which #1424 left in place because the server had
no route. It now sends the same `DELETE`, so the v0.3 REST client can
delete a config too (added after review).

Tests: `test_delete_push_notification` (handler) and
`test_delete_push_notification_config_v03` (route) fail on main and pass
with this change. After review:
`test_compat_rest_transport_delete_task_push_notification_config` now
checks the request the client sends instead of expecting
`NotImplementedError`,
`test_compat_rest_client_deletes_push_notification_config` sends the
delete from the client through the real v0.3 REST routes, and
`test_delete_push_notification_config_v03_unknown_task_returns_404`
covers `TaskNotFoundError`. The client tests fail with the old client
code.
- `uv run pytest tests/compat/v0_3/ -k "delete_push_notification or
deletes_push_notification"`: 8 failed with the three compat source files
from main, 8 passed with this change
- `uv run pytest --cov=a2a --cov-fail-under=88` after merging current
main: 2576 passed, 207 skipped, 4 xfailed, 1 xpassed; coverage 93.57%.
In one of three runs
`test_scenario_auth_required_side_channel[blocking-legacy]` failed and
then passed on rerun; it does not touch this code.
- `tests/integration/cross_version/client_server/test_client_server.py`
(against `a2a-sdk` 0.3.24): 4 passed
- `uv run ruff check` and `uv run ruff format --check`: clean; `uv run
ty check`: no errors (3 warnings, all in files this PR does not touch)

Worth checking: v0.3 routes are registered before the `/{tenant}` mount,
so a v1.0 tenant literally named `v1` deleting at this path now reaches
the v0.3 handler. That is already true for the existing v0.3 GET on the
same path. Deleting an unknown config id returns 200 `{}`, as it does on
the other transports.

- [x] Follow the CONTRIBUTING Guide.
- [x] Make your Pull Request title in the conventionalcommits.org
specification.
- [x] Ensure the tests and linter pass
- [ ] Appropriate docs were updated (if necessary)

Fixes #1441

---------

Co-authored-by: YusefSyed <[email protected]>
Co-authored-by: Mateusz Iwaniuk <[email protected]>