Binder bean validation is not triggered properly in Vaadin 24

[jcgueriaud1]

Description

When I set a validator on the binder, the setValidationStatusHandler does not show the error.

In Vaadin 23, the error was displayed.

Expected outcome

The error should be displayed and the binder status should be in error.

Minimal reproducible example

public class HelloWorldView extends HorizontalLayout {

    private Binder<FakeBean> binder = new Binder<>();

    private TextField name = new TextField("Name");
    private TextField name2 = new TextField("Name2");

    private Span errorMessage = new Span();

    public HelloWorldView() {
        FakeBean fakeBean = new FakeBean();
        binder.forField(name).asRequired("name is required")
                .bind(FakeBean::getName, FakeBean::setName);
        binder.forField(name2).asRequired("name2 is required")
                .bind(FakeBean::getName2, FakeBean::setName2);
        binder.setBean(fakeBean);
        binder.withValidator(bean ->
                        Objects.equals(bean.getName(), "test") || Objects.equals(bean.getName2(), "test"),
                "At least one field should be test"
        );
        binder.setValidationStatusHandler(status -> {
            System.out.println("Errors " + status.getValidationErrors().size());
            if (!status.getBeanValidationErrors().isEmpty()) {
                errorMessage.setText(status.getBeanValidationErrors().get(0).getErrorMessage());
                errorMessage.setVisible(true);
            } else {
                errorMessage.setVisible(false);
            }
        });
        add(name, name2, errorMessage);
    }

}

See these 2 branches:
https://github.com/jcgueriaud1/spring-proxy-issue/tree/bean-validation-v24
https://github.com/jcgueriaud1/spring-proxy-issue/tree/bean-validation-v23

Steps to reproduce

Open the view type xx as no field value = test the error should be displayed.

Environment

Vaadin version(s): 24.1.4

Browsers

No response

[vursen]

The issue goes away when I remove the validated event subscription from addValidationStatusChangeListener. It appears Binder doesn't run top-level validators when revalidating on ValidationStatusChangeEvent that we dispatch in addValidationStatusChangeListener:

https://github.com/vaadin/flow-components/blob/a33f718985c95d28f95899ee1cbf93b40d8389d0/vaadin-text-field-flow-parent/vaadin-text-field-flow/src/main/java/com/vaadin/flow/component/textfield/TextArea.java#L325-L330

Although, it does run them when the revalidation is caused by ValueChangeEvent.

This gives me the impression that it might be a bug in Binder. @mshabarov Could you check that please?

[mshabarov]

@vursen the behaviour described above doesn't seem correct to me.
status.getValidationErrors() returns non-empty collection of errors in V23 and V24.3 and the error message is shown properly.
However, with V24.1 and V24.2, the validationStatusHandler is called 3 times, giving 1 error for the first call, and 0 errors for subsequent last two calls.
Only this single fact makes me think that it's a buggy behavior.

I would expect that if I set the binder-level validator with withValidator, then status.getValidationErrors() should return non-zero errors, if this validator predicate returns false.

So far I think this is a bug in Flow Binder.

By the way, I didn't get how addValidationStatusChangeListener impacts the status handler? They are kind of separate hooks.

[mshabarov]

Similar behaviour is described here by the way.

[vaadin-bot]

This ticket/PR has been released with Vaadin 24.3.4.

[rolfwoll]

I have a similar problem to this related to DateTimePickers in Vaadin 24.4.7

If I change Jean-Christophe Gueriaud's code snipplet above to use LocalDateTimes and DateTimePickers, then I get the same problem again.

`public class HelloWorldView extends HorizontalLayout {

private Binder<FakeBean> binder = new Binder<>();

private DateTimePicker date1 = new DateTimePicker("Date1");
private DateTimePicker date2 = new DateTimePicker("Date2");

private IntegerField field = new IntegerField("test");

private Span errorMessage = new Span();

public HelloWorldView() {
    FakeBean fakeBean = new FakeBean();
    binder.forField(date1).asRequired("date1 is required")
            .bind(FakeBean::getDate1, FakeBean::setDate1);
    binder.forField(date2).asRequired("date2 is required")
            .bind(FakeBean::getDate2, FakeBean::setDate2);
    binder.setBean(fakeBean);
    binder.withValidator(bean ->
                    bean.getDate1() == null || bean.getDate2()== null || bean.getDate1().isBefore(bean.getDate2()),
            "date1 should be before date 2"
    );
    binder.setValidationStatusHandler(status -> {
        System.out.println("Errors " + status.getValidationErrors().size());
        if (!status.getBeanValidationErrors().isEmpty()) {
            errorMessage.setText(status.getBeanValidationErrors().get(0).getErrorMessage());
            errorMessage.setVisible(true);
        } else {
            errorMessage.setVisible(false);
        }
    });
    field.setMin(0);
    add(date1, date2, errorMessage, field, new Button("Clear", e-> field.clear()));
}

}
`
LocalDateTime date1 and date2 properties are added to FakeBean of course.

In this case, validationStatusHandler is called 2 times, first time with the error from the bean level validator and the second time without any errors which clears the previous error message, so it matches the behaviour of this ticket even though it is marked as closed.