Hey, can Flyte handle

field

defaults on dataclasses? Dataclasses can't have list / dict / set defaults (https://stackoverflow.com/q/52063759) and you have to resort to something like

str_list: List[str] = field(default_factory=lambda: ["a", "b"])

instead, but on Flyte console when launching a workflow it just shows an empty list for me.

I think i may be able to handle constants, definitely not

lambda

as the dataclasses are converted to a json schema

it should be possible to execute that default_factory to get the constant it returns though no?

cc: @Kevin Su

My task

@dataclass_json
@dataclass
class Args(object):
    max_iter: int = 0
    str_list: List[str] = field(default_factory=lambda: ["a", "b"])


@task
def t1(schema: Args = Args(1)):
    print(schema)

I was using 1.1.1, but updated to 1.2.1 and have the same problem there. Was it filled in the launch workflow form for you too? // will try to make a repro later

I’m using the latest version of sandbox

I just ran into this as well. I my case, the list is only filled if I actually have a default parameter that creates an instance of the dataclass.

@task
def t1(schema: Args = Args(1)):
    print(schema)

If, on the other hand there is no default parameter (it is only set in a launchplan in our case), it is empty like in @Robin Kahlow's case:

@task
def t1(schema: Args):
    print(schema)

@Kevin Su what happens if you leave out the default parameter?

So tasks do not support default parameters

Interesting though that in this case Flyteconsole showing the list entries only seems to work with a default parameter on task and workflow 🤔

nice to know, i still hadn't figured it out until you mentioned this

Wdym, default parameter on the task?

@Ketan (kumare3) like this:

@task
def t1(schema: Args = Args(1)):
    print(schema)

You need to add the dataclass constructor call

Args()

as a default parameter to the task. It seems only then Flyte will fill in lists defined as default in the

Args

dataclass.

This is odd, I think this is because of json schema