The "required" tamper does not work with false, zero etc. values

Alright, maybe we need two settings then:

• Count the number 0 as empty
• Count the boolean false as empty

The first text is taken from Views, where that is used to determine wether or not there is a result. We might even copy the method Drupal\views\Plugin\views\field\FieldPluginBase::isValueEmpty() to the Required plugin.

And I think we need to have these settings enabled by default, for backwards compatibility.

I see. But you mean "have these settings" disabled by default, right? I mean, if you want to have backwards compatibility, they are supposed to be disabled, since currently they act as if they were off.

No, the current behavior is as follows:

• The number 0 is considered to represent an empty value.
• The boolean false is considered to represent an empty value.

So if the passed value is 0 or false, the item will not be processed currently.

So if you want the item to be processed on 0 or false (but not on null), the proposed settings "Count the number 0 as empty" and "Count the boolean false as empty" should be disabled. And to preserve the current behaviour, these settings should therefore be enabled by default.

Ah, yes, you're right haha I got confused in my own initial report :D