I am seeing some new weirdness in the Flow Custom Run UI when trying to set Union fields, the Union object I select and the values that I set on it seem to be lost when starting the flow. The values are missing from the parameters JSON in the flow run

Can you share your inputs (how you are submitting), and paramters after the flow run starts?

Yeah, I'll try to distill the issue into a simpler param model

I’ve reported a recent JSON bug with the UI, so just trying to determine if this is related, or separate

Gotcha - maybe this will help for now: Model definition looks something like

class ParamGroup(BaseModel):
   another_field: Int
   specific_param: Union[ThingOne, ThingTwo, Etc] = Field(description="whatever")

class Params(BaseModel):
   a_field: Int
   param_group: ParamGroup

The UI renders the union field fine, and each model in the union has fields that I can set fine. But then when I run the flow the params look something like:

{
   a_field: 123
   param_group: {
      another_field: 123
   }
}

Notice

specific_param

is not present. And then another layer of weirdness is when I make the JSON myself, like:

{
   a_field: 123
   param_group: {
      another_field: 123
      specific_param: {whatever: 123}
   }
}

and paste it into the JSON for a new flow run, the value is lost and the resulting text is

{
   a_field: 123
   param_group: {
      another_field: 123
      specific_param: {}
   }
}

So I want to make sure I follow ok

Yeah putting them in the Custom parameters tab. It doesn't work right away if I paste in the full JSON, for some reason when I first paste in the json the field-value-pairs set on the Union object get lost, then if I delete it all and re-paste it works.

Could you do a simple screen capture / recording like 20 seconds, or a repro for me if possible? We’ve had a couple UI bugs, and in the process of fixing this one, want to make sure we hit all the cases

Yeah I will put together a repro

Thank you @Max Eggers, I’m looking / testing this now

Thank you!

Just verifying, previously this was working for you right ? With no changes on inputs or flows ?

correct

I’ve been working with the backend team on this, a fix is being worked on related

👍 sounds good, thank you

https://github.com/PrefectHQ/prefect-ui-library/pull/1563 is being merged, I’m working with the team to make sure this satisfied your repro as well

👍 thanks for the update

We tested this successfully in staging, but currently working through some other test cases before this gets released, I’ll keep you posted

Sweet!

please keep us posted we can test out when the release is pushed. This caused us to fail runs as validation errors but if it failed a bit more silently in parameter passing it may cost us several thousand dollars of compute

Release should be pushed today - I’m sorry to hear that

Is this fixed with the latest release?

Ah yes - this was pushed out yesterday

Cool - looks like my repro is fixed - thank you!

I was worried for a second because we were using your repro to test 😮

🙂 I was just holding off testing until I heard about a deployment

gotcha, yea! There were a couple fixes pushed, but I think it shored up all the reports we’d seen / repro’d

Sweet - thanks again!