fix(client): prevent crash on non-dict JSON-RPC error responses

Chained .get() calls on the error field caused an AttributeError
when the server returned a non-dict error value (e.g. a plain string
or null).

Author: fguillot

kanboard.py

@@ -145,8 +145,9 @@ def _parse_response(response: bytes) -> Any:
         try:
             body = json.loads(response.decode(errors="ignore"))
 
-            if "error" in body:
-                message = body.get("error").get("message")
+            error = body.get("error")
+            if error:
+                message = error.get("message") if isinstance(error, dict) else str(error)
                 raise ClientError(message)
 
             return body.get("result")

tests/test_kanboard.py

@@ -83,6 +83,13 @@ def test_application_error(self):
         with self.assertRaises(kanboard.ClientError, msg="Internal error"):
             self.client.remote_procedure()
 
+    def test_application_error_non_dict(self):
+        body = b'{"jsonrpc": "2.0", "error": "Something went wrong", "id": 123}'
+        self.urlopen.return_value.read.return_value = body
+
+        with self.assertRaises(kanboard.ClientError, msg="Something went wrong"):
+            self.client.remote_procedure()
+
     def test_async_method_call_recognised(self):
         method_name = "some_method_async"
         result = self.client.is_async_method_name(method_name)