register_push_device: Add an error code to push-not-configured error.

This commit adds an error code to make it easier for clients
to identify when push device registration is rejected due to
server not being configured to use push notification service.

Fixes part of 35368.

zerver/lib/exceptions.py

@@ -61,6 +61,7 @@ class ErrorCode(Enum):
     HOSTNAME_ALREADY_IN_USE_BOUNCER_ERROR = auto()
     INVALID_BOUNCER_PUBLIC_KEY = auto()
     REQUEST_EXPIRED = auto()
+    PUSH_SERVICE_NOT_CONFIGURED = auto()
 
 
 class JsonableError(Exception):
@@ -863,3 +864,15 @@ class InvalidEncryptedPushRegistrationError(JsonableError):
     @override
     def msg_format() -> str:
         return _("Invalid encrypted_push_registration")
+
+
+class PushServiceNotConfiguredError(JsonableError):
+    code = ErrorCode.PUSH_SERVICE_NOT_CONFIGURED
+
+    def __init__(self) -> None:
+        pass
+
+    @staticmethod
+    @override
+    def msg_format() -> str:
+        return _("Server is not configured to use push notification service.")

zerver/openapi/zulip.yaml

@@ -12619,7 +12619,7 @@ paths:
                       {
                         "result": "error",
                         "msg": "Server is not configured to use push notification service.",
-                        "code": "BAD_REQUEST",
+                        "code": "PUSH_SERVICE_NOT_CONFIGURED",
                       }
                     description: |
                       Error when the server is not configured to use push notification service:

zerver/views/push_notifications.py

@@ -15,6 +15,7 @@ from zerver.lib.exceptions import (
     JsonableError,
     MissingRemoteRealmError,
     OrganizationOwnerRequiredError,
+    PushServiceNotConfiguredError,
     RemoteRealmServerMismatchError,
     ResourceNotFoundError,
 )
@@ -280,7 +281,7 @@ def register_push_device(
     encrypted_push_registration: str,
 ) -> HttpResponse:
     if not (settings.ZILENCER_ENABLED or uses_notification_bouncer()):
-        raise JsonableError(_("Server is not configured to use push notification service."))
+        raise PushServiceNotConfiguredError
 
     # Idempotency
     already_registered = PushDevice.objects.filter(