feat: expose validation error messages on invalid input errors (#616)

Port the getValidationErrorMessages interface from the JavaScript SDK.
SeamHttpInvalidInputError now carries the validation_errors from the API
error response and exposes get_validation_error_messages(param_name),
which returns the messages for a request parameter or an empty list when
that parameter has none.


Claude-Session: https://claude.ai/code/session_012RfnESV5b57QDoxMggXdM9

Co-authored-by: Claude <noreply@anthropic.com>

Author: razor-x

seam/client.py

@@ -146,6 +146,7 @@ def _handle_error_response(self, response: Response):
         }
 
         if error_type == "invalid_input":
+            error_details["validation_errors"] = error.get("validation_errors")
             raise SeamHttpInvalidInputError(error_details, status_code, request_id)
 
         raise SeamHttpApiError(error_details, status_code, request_id)

seam/exceptions.py

@@ -1,4 +1,4 @@
-from typing import Any, Dict, Optional
+from typing import Any, Dict, List, Optional
 from .resources import ActionAttempt
 
 
@@ -86,6 +86,19 @@ def __init__(
 
         super().__init__(error, status_code, request_id)
         self.code = "invalid_input"
+        self._validation_errors = error.get("validation_errors") or {}
+
+    def get_validation_error_messages(self, param_name: str) -> List[str]:
+        """
+        The validation messages for a request parameter, or an empty list when
+        that parameter has none.
+
+        :param param_name: Name of the request parameter
+        :type param_name: str
+        :rtype: List[str]
+        """
+
+        return self._validation_errors.get(param_name, {}).get("_errors", [])
 
 
 # Action Attempt

test/http_error_test.py

@@ -45,6 +45,20 @@ def test_seam_http_throws_invalid_input_error(server):
     assert err.status_code == 400
     assert err.code == "invalid_input"
     assert err.request_id.startswith("request")
+    assert err.get_validation_error_messages("device_ids") == [
+        "Expected array, received number"
+    ]
+
+
+def test_seam_http_invalid_input_error_has_no_messages_for_unknown_param(server):
+    endpoint, seed = server
+
+    seam = Seam(api_key=seed["seam_apikey1_token"], endpoint=endpoint)
+
+    with pytest.raises(SeamHttpInvalidInputError) as exc_info:
+        seam.devices.list(device_ids=4242)
+
+    assert exc_info.value.get_validation_error_messages("non_existent_param") == []
 
 
 def test_seam_http_throws_http_error_on_non_standard_response(server):