#6628 [BUG] [flytekit] Incorrect error message when converting types (referring to wrong argument) Issue created by pimdh Flyte & Flytekit version Flytekit 1.16.3 (also seems present on master) Describe the bug When there's an error in type conversion, the error message always refer the last argument, even if that's not where the error is. This is caused by a bug in the following code: https://github.com/flyteorg/flytekit/blob/9effe915c0dfdd1b9870ce0539ed0aec3ccda80c/flytekit/core/type_engine.py#L1579 The variable

k

in this code will always refer to the final arg, even if that's not where the error occurred. To reproduce, run from flytekit import task, workflow from flytekit.types.directory import FlyteDirectory @task def process_directory(input_dir: FlyteDirectory, description: str) -> str: """Process a directory with a description.""" return f"Processing directory: {input_dir.path} with description: {description}" @workflow def main_workflow(input_dir: FlyteDirectory, description: str) -> str: """Main workflow that calls the task.""" return process_directory(input_dir=input_dir, description=description) if name == "__main__": # Incorrectly passing empty string as first argument (should be FlyteDirectory) result = main_workflow(input_dir=FlyteDirectory(""), description="Sample processing job") print(result) which will give the unhelpful errormessage:

TypeTransformerFailedError: Error encountered while converting inputs of 'example_flyte_task.process_directory':
  Error converting input 'description' at position 1:
Literal value: Flyte Serialized object (Literal):
  scalar:
    primitive:
      string_value: Sample processing job
Expected Python type: <class 'str'>
Exception: USER:AssertionError: error=Expected a directory, but the given uri '' is not a directory.

Expected behavior I'd expect an error message like the following (achieved by removing the 2nd arg):

TypeTransformerFailedError: Error encountered while converting inputs of 'example_flyte_task.process_directory':
  Error converting input 'input_dir' at position 0:
Literal value: Flyte Serialized object (Literal):
  scalar:
    blob:
      metadata:
        type:
          dimensionality: 1
Expected Python type: <class 'flytekit.types.directory.types.FlyteDirectory'>
Exception: USER:AssertionError: error=Expected a directory, but the given uri '' is not a directory.

Additional context to reproduce No response Screenshots No response Are you sure this issue hasn't been raised already? • Yes Have you read the Code of Conduct? • Yes flyteorg/flyte