fix: validate event

[qu3vipon]

Resolve: #310

Validate EventChain explicitly, so other types will be caught as a ValueError

ValueError: Invalid event chain: {state. some_var}

[picklelo]

I think here the code is correct but the comment is incorrect.

Can we revert the code, but fix the comment to say:

# If it's a var, return it.

[picklelo]

Maybe in addition, we need the EventChain check? But we definitely need this current one. What code did you run that raised the ValueError?

[qu3vipon]

EventChain check is for CustomComponent.

I run the same code from #310.

class State(pc.State):
    some_var: bool

def index():
    return pc.box(pc.icon(tag="AddIcon", on_click=State.some_var))

some_var is passed as a BaseVar, it is a child class of Var, so it is caught at first if statement.

[qu3vipon]

Can you explain more about why we definitely need the current one when we create EventChain? BaseVar shouldn't be returned in my opinion.

[picklelo]

Ahh I see - you're right this is causing the other bug it looks like. We need this line for the CustomComponent feature that I'm working on (it's not released yet, but it will allow you to create memoized React components for better performance).

But I think in adding that line it caused this other bug. Let me think a bit more on how to resolve this.

Basically for CustomComponent it can take in a Var, but for regular components it should not allow it.

[picklelo]

Maybe we can add a line like

if isinstance(self, CustomComponent):
    if isinstance(value, Var):
        return value

Then it should fix this bug, but still work for the new feature.

[qu3vipon]

Ok. Should I change the code as you suggest? or just close this pr and wait for your new feature?

[qu3vipon]

I just did a quick fix as you suggest. Thanks for the help.

[picklelo]

thanks for the fix!