Just asking, but what about isRoot() instead, as in FormInterface::isRoot() ?

@ogizanagi FormInterface::isRoot() is not accessible from twig and FormView does not implement this interface.

Does anyone knows why i am getting this error in build AppVeyor build failed

The problem here is that it does not make such sense to add methods like isRoot or hasParent on a value object with public properties as FormView, and using form.parent or form.root has the same effect in Twig that checking the public property so adding it to hardcode it looks weird somehow.

The real issue I guess come from Twig and how it tries to access an attributes because FormView has both public properties and array access, but the last has a precedence so it will first look for named children.

Maybe we should just better document how to access children via offset get when they have the same name as a view property (e.g form['parent'], form['children'], form['vars']) and suggest to avoid such collision?

@ogizanagi FormInterface::isRoot() is not accessible from twig and FormView does not implement this interface.

@bhavin-nakrani : I was asking about naming the method isRoot instead of hasParent and reverse the logic inside 😅

The real issue I guess come from Twig and how it tries to access an attributes because FormView has both public properties and array access, but the last has a precedence so it will first look for named children.

Maybe we should just better document how to access children via offset get when they have the same name as a view property (e.g form['parent'], form['children'], form['vars']) and suggest to avoid such collision?

@HeahDude : IIUC, this won't solve the mentioned issue, where form.parent will always return something in case the form has a child named parent. Thus, no simple way to know if it's a child or a parent :/

@ogizanagi Yes what I implicitly suggest here is to think about the precedence in Twig, checking object (properties and methods) in an early return before checking for array and ArrayAccess, but that sounds like a big BC break (maybe doable with the upcoming 2.0?).

The opposite is not working either because if one wants to test if a form has a child named "parent" it may return the actual parent even using form['parent'] because [] has the same behavior for objects since it is the only way to make the call dynamic using a twig variable to determine the property/method.

So it may worth to say a word in the doc about it anyway. Although hardcoding hasMethod might help to ensure the checks both ways but IMO it keeps looking like a hack adding this method in FormView to work around this.

Imo. it's worth reserving form.parent as is. A child named liked like that can be accessed via form.children['parent'], same for having form.root as proposed in #20369

Closing this PR as there does not seem to have any more activity and the PR cannot be merged as is. Feel free to reopen though.