Cant enter list/array into custom parameter in Orion UI

[Wingmore]

I cant enter lists/array into the Orion UI Custom Parameters of deployments. Get an error if I try:

prefect.exceptions.ParameterTypeError: Flow run received invalid parameters:
 - capsule_ids: value is not a valid integer
 - capsule_ids: value is not a valid list

See also: https://discourse.prefect.io/t/flow-run-received-invalid-parameters-value-is-not-a-valid-list/2310

[serinamarie]

Hi @Wingmore, can you provide an MRE for this?

[Wingmore]

test_validation.py:

from typing import Union, List
from prefect import flow

@flow(log_prints=True)
def my_flow(
    some_list: Union[int, List[int]] = 5
):
    if type(some_list) == int:
        print(some_list)
    else:
        for i in some_list:
            print(i)

if __name__ == "__main__":
    my_flow([1,2,3])

Create Deployment

prefect deployment build test_validation.py:my_flow --name input_validation -a

In Orion UI I enter

When I hit run, I am greeted with this:

15:50:16.587 | ERROR   | Flow run 'psi4-ventani-b' - Validation of flow parameters failed with error:
Traceback (most recent call last):
  File "/home/usr/anaconda3/envs/mtt-prefect-env/lib/python3.9/site-packages/prefect/engine.py", line 296, in retrieve_flow_then_begin_flow_run
    parameters = flow.validate_parameters(flow_run.parameters)
  File "/home/usr/anaconda3/envs/mtt-prefect-env/lib/python3.9/site-packages/prefect/flows.py", line 339, in validate_parameters
    raise ParameterTypeError.from_validation_error(exc) from None
prefect.exceptions.ParameterTypeError: Flow run received invalid parameters:
 - some_list: value is not a valid integer
 - some_list: value is not a valid list

And this is what the parameter tab looks like.

[Wingmore]

Note this may be an issue with Union... If I ONLY have a list, then it seems to works ok. That is, if I have some_list: List[int] as the arguments

[serinamarie]

I was able to reproduce the issue. I believe this discussion is relevant to the UI team, so I'll create an issue from this. For now, I'm glad you have a workaround!