Made a quick investigation and from what I understand, Binder currently listens to input, change, and blur events to update its state and trigger validation:

However, this is apparently not always sufficient. I'm also not sure if running validation on input makes sense for all components, as not all of them update their value on input.

So, assuming that different components can have different validation triggers, it might be better to delegate the validation triggering to the component itself by listening to the validated event instead. For text fields, it would trigger validation on change and additionally on input if the field is already invalid (since this is the current behavior of the web component). For date picker, validation would be triggered on change, unparsable-change, overlay close, blur, etc; there are plenty of triggers.

Possibly related to #2341

I’m reopening this issue as it still persists. Based on the tests, the referenced fix seems to address the case where an unparsable value is set by the developer via the value property, which is a slightly different issue. The issue described in this ticket occurs when the user enters an unparsable value and, for example, presses Enter. In this scenario, neither change nor blur are fired, so Binder isn't notified about the validation.

In our discussion with Anton, we agreed that a reasonable solution would be to replace the input, change, and blur event subscriptions with a subscription to the validated event when the field is a Vaadin component.

This ticket/PR has been released with Hilla 24.5.1.

This ticket/PR has been released with Hilla 24.6.0.alpha3 and is also targeting the upcoming stable 24.6.0 version.