fix(proto-plus): add context to TypeErrors during message manipulation#17682
fix(proto-plus): add context to TypeErrors during message manipulation#17682guptaarima wants to merge 1 commit into
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This pull request improves error handling in packages/proto-plus/proto/message.py by wrapping protocol buffer initialization and field assignment operations in try-except blocks. When a TypeError occurs during these operations, a more descriptive TypeError is raised with context about the class name, field key, and the underlying error. I have no feedback to provide as there are no review comments.
parthea
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Please could you address the lint failure? Please could you also add tests to avoid regressions? For example,
def test_invalid_initialization_type_error():
"""Verify that bad types passed to __init__ raise a descriptive TypeError."""
class UserProfile(proto.Message):
username = proto.Field(proto.STRING, number=1)
age = proto.Field(proto.INT32, number=2)
with pytest.raises(TypeError) as excinfo:
# Passing a list where a string is expected
UserProfile(username=["not", "a", "string"])
error_msg = str(excinfo.value)
assert "Failed to initialize UserProfile" in error_msg
assert "Underlying error" in error_msg
# Ensure the original exception is chained via 'from'
assert isinstance(excinfo.value.__cause__, TypeError)
def test_invalid_assignment_type_error():
"""Verify that bad types assigned via __setattr__ raise a descriptive TypeError."""
class UserProfile(proto.Message):
username = proto.Field(proto.STRING, number=1)
age = proto.Field(proto.INT32, number=2)
profile = UserProfile()
with pytest.raises(TypeError) as excinfo:
# Assigning a dictionary where an integer is expected
profile.age = {"invalid": "type"}
error_msg = str(excinfo.value)
assert "Failed to set field 'age' on UserProfile" in error_msg
assert "{'invalid': 'type'}" in error_msg
# Ensure the original exception is chained via 'from'
assert isinstance(excinfo.value.__cause__, TypeError)
We may also need to patch proto/marshal/marshal.py as the test fails with FAILED tests/test_message.py::test_invalid_assignment_type_error - AttributeError: 'ProtoType' object has no attribute 'DESCRIPTOR'
Patch for proto/marshal/marshal.py:
diff --git a/packages/proto-plus/proto/marshal/marshal.py b/packages/proto-plus/proto/marshal/marshal.py
index 81f1a473bf8..3133467560d 100644
--- a/packages/proto-plus/proto/marshal/marshal.py
+++ b/packages/proto-plus/proto/marshal/marshal.py
@@ -224,7 +224,8 @@ class BaseMarshal:
# annotation. We need to do the conversion based on the `value`
# field's type.
if isinstance(value, dict) and (
- proto_type.DESCRIPTOR.has_options
+ hasattr(proto_type, "DESCRIPTOR")
+ and proto_type.DESCRIPTOR.has_options
and proto_type.DESCRIPTOR.GetOptions().map_entry
):
recursive_type = type(proto_type().value)
|
Hi @guptaarima, I'm going to switch this to draft but please feel free to mark it ready for review once the presubmits are green |
2 participants
Summary of the issue:
Context:
When using proto-plus, if a user assigns a value of an incorrect type to a message field (e.g., assigning a List[int] to a field expecting a MutableSequence[str]), the error raised originates from the underlying protocol buffer library and lacks specific details about the source of the error within the proto-plus message structure.
Actual Behavior:
The library propagates a generic TypeError from the core protobuf implementation (e.g., TypeError: bad argument type for built-in operation). This error message is cryptic because it does not identify which message class or field name received the invalid type, making it difficult for users to pinpoint the cause of the type mismatch in their code.
Expected Behavior:
proto-plus should catch these underlying TypeError exceptions during field assignments or message merging (like MergeFrom). It should then raise a new, more informative TypeError that includes context about the specific proto-plus message class and the field name involved.
For example, an improved error message could look like:
TypeError: Invalid type for field 'field_name' in message 'MessageName'. Expected but got .
This fix will significantly improve the debuggability of type-related errors when using proto-plus.