Refactor: Extract JSONRPC error models to resolve circular dependency

- Create `src/a2a/server/jsonrpc_models.py` to hold exception classes.
- Remove `src/a2a/server/apps/jsonrpc/errors.py`.
- Update imports across server handlers, utils, and tests.
- Fix logic in DefaultRequestHandler.on_get_task_push_notification_config to handle list of configs.

Author: muscariello

src/a2a/server/apps/jsonrpc/jsonrpc_app.py

@@ -18,14 +18,14 @@
     HTTP_EXTENSION_HEADER,
     get_requested_extensions,
 )
-from a2a.server.apps.jsonrpc.errors import (
+from a2a.server.context import ServerCallContext
+from a2a.server.jsonrpc_models import (
     InternalError,
     InvalidParamsError,
     InvalidRequestError,
     JSONParseError,
     MethodNotFoundError,
 )
-from a2a.server.context import ServerCallContext
 from a2a.server.request_handlers.jsonrpc_handler import JSONRPCHandler
 from a2a.server.request_handlers.request_handler import RequestHandler
 from a2a.server.request_handlers.response_helpers import build_error_response

src/a2a/server/apps/jsonrpc/errors.py src/a2a/server/jsonrpc_models.pysrc/a2a/server/apps/jsonrpc/errors.py renamed to src/a2a/server/jsonrpc_models.py

@@ -35,6 +35,7 @@
     ListTaskPushNotificationConfigRequest,
     ListTaskPushNotificationConfigResponse,
     Message,
+    PushNotificationConfig,
     SendMessageRequest,
     SetTaskPushNotificationConfigRequest,
     StreamResponse,
@@ -514,23 +515,24 @@ async def on_get_task_push_notification_config(
             raise ServerError(error=UnsupportedOperationError())
 
         task_id = _extract_task_id(params.name)
+        config_id = _extract_config_id(params.name)
         task: Task | None = await self.task_store.get(task_id, context)
         if not task:
             raise ServerError(error=TaskNotFoundError())
 
-        push_notification_config = await self._push_config_store.get_info(
-            task_id
+        push_notification_configs: list[PushNotificationConfig] = (
+            await self._push_config_store.get_info(task_id) or []
         )
-        if not push_notification_config or not push_notification_config[0]:
-            raise ServerError(
-                error=InternalError(
-                    message='Push notification config not found'
+
+        for config in push_notification_configs:
+            if config.id == config_id:
+                return TaskPushNotificationConfig(
+                    name=params.name,
+                    push_notification_config=config,
                 )
-            )
 
-        return TaskPushNotificationConfig(
-            name=params.name,
-            push_notification_config=push_notification_config[0],
+        raise ServerError(
+            error=InternalError(message='Push notification config not found')
         )
 
     async def on_subscribe_to_task(

src/a2a/server/request_handlers/default_request_handler.py

@@ -28,8 +28,8 @@
     HTTP_EXTENSION_HEADER,
     get_requested_extensions,
 )
-from a2a.server.apps.jsonrpc.errors import JSONParseError
 from a2a.server.context import ServerCallContext
+from a2a.server.jsonrpc_models import JSONParseError
 from a2a.server.request_handlers.request_handler import RequestHandler
 from a2a.types import a2a_pb2
 from a2a.types.a2a_pb2 import AgentCard

src/a2a/server/request_handlers/grpc_handler.py

@@ -8,13 +8,13 @@
 from google.protobuf.json_format import MessageToDict
 from jsonrpc.jsonrpc2 import JSONRPC20Response
 
-from a2a.server.apps.jsonrpc.errors import (
+from a2a.server.context import ServerCallContext
+from a2a.server.jsonrpc_models import (
     InternalError as JSONRPCInternalError,
 )
-from a2a.server.apps.jsonrpc.errors import (
+from a2a.server.jsonrpc_models import (
     JSONRPCError,
 )
-from a2a.server.context import ServerCallContext
 from a2a.server.request_handlers.request_handler import RequestHandler
 from a2a.types.a2a_pb2 import (
     AgentCard,

src/a2a/server/request_handlers/jsonrpc_handler.py

@@ -6,10 +6,10 @@
 from google.protobuf.message import Message as ProtoMessage
 from jsonrpc.jsonrpc2 import JSONRPC20Response
 
-from a2a.server.apps.jsonrpc.errors import (
+from a2a.server.jsonrpc_models import (
     InternalError as JSONRPCInternalError,
 )
-from a2a.server.apps.jsonrpc.errors import (
+from a2a.server.jsonrpc_models import (
     JSONRPCError,
 )
 from a2a.types.a2a_pb2 import (

src/a2a/server/request_handlers/response_helpers.py

@@ -15,10 +15,10 @@
         Response = Any
 
 
-from a2a.server.apps.jsonrpc.errors import (
+from a2a.server.jsonrpc_models import (
     InternalError as JSONRPCInternalError,
 )
-from a2a.server.apps.jsonrpc.errors import (
+from a2a.server.jsonrpc_models import (
     JSONParseError,
     JSONRPCError,
 )

src/a2a/utils/error_handlers.py

@@ -6,7 +6,7 @@
 from starlette.testclient import TestClient
 
 from a2a.server.apps import A2AFastAPIApplication, A2AStarletteApplication
-from a2a.server.apps.jsonrpc.errors import JSONParseError
+from a2a.server.jsonrpc_models import JSONParseError
 from a2a.types import (
     InvalidRequestError,
 )

tests/server/apps/jsonrpc/test_serialization.py

@@ -7,7 +7,7 @@
 
 from a2a.server.events.event_consumer import EventConsumer, QueueClosed
 from a2a.server.events.event_queue import EventQueue
-from a2a.server.apps.jsonrpc.errors import JSONRPCError
+from a2a.server.jsonrpc_models import JSONRPCError
 from a2a.types import (
     InternalError,
 )

tests/server/events/test_event_consumer.py

@@ -11,7 +11,7 @@
 import pytest
 
 from a2a.server.events.event_queue import DEFAULT_MAX_QUEUE_SIZE, EventQueue
-from a2a.server.apps.jsonrpc.errors import JSONRPCError
+from a2a.server.jsonrpc_models import JSONRPCError
 from a2a.types import (
     TaskNotFoundError,
 )