Binder.removeBinding issue

[nbabb]

In Vaadin flow 1.0.5, I have several fields bound to a Binder instance. When I remove a binding (where there are still other bound properties) it is calling unbind. It seems like it should only call unbind when the count of bound properties is zero? Here is the code.

public void removeBinding(String propertyName) {
    Objects.requireNonNull(propertyName, "Property name may not be null");
    Optional.ofNullable(boundProperties.get(propertyName))
            .ifPresent(Binding::unbind);
}

I end up receiving errors after I remove the binding

java.lang.NullPointerException: This Binding is no longer attached to a Binder
at java.base/java.util.Objects.requireNonNull(Objects.java:246) ~[na:na]
at com.vaadin.flow.data.binder.Binder$BindingImpl.validate(Binder.java:1027) ~[flow-data-1.0.5.jar:na]

from my other bound fields that are still using the binding.

Perhaps I'm misunderstanding how this should work? See vaadin/framework#11280 for reference

[ZheSun88]

The first thing i would suggest you is updating your flow version to the latest ones, ( if you are using flow separately, the version number is 1.0.10). could you try with that one?

[atistrcsn]

vaadin/framework#11280

The WorkaroundBinder mentioned in @lulnope's answer is actually a good temporary solution.
It should be included in a bugfix. I don't have experience how to prepare one.

@ZheSun88 This WorkaroundBinder was worked for me, I have flow version 1.4.4.

[denis-anisimov]

Looks like this is a bug in Binder.

Refer to vaadin/framework#11280 (comment) to fix it:

The issue is located in Binder class in its protected void removeBindingInternal(Binding<T, ?> binding) method. Currently it looks as follows:

protected void removeBindingInternal(Binding<BEAN, ?> binding) {
        if (bindings.remove(binding)) {
            boundProperties.entrySet()
                    .removeIf(entry -> entry.getValue().equals(binding));
        }
    }

it's missing: changedBindings.remove(binding)
which should resolve this error:
java.lang.NullPointerException: This Binding is no longer attached to a Binder