ko.validation.group unexpected null entry

[tomalec]

I'm not sure if I'm using group correctly, but

I try to get array of errors from my observableArray elements
http://jsfiddle.net/tomalec/DWACW/
The problem is that if you enter both invalid values, null appears in ko.validation.group(self.rows, { deep: true, observable: true });

I found that null comes from self.rows.isValid(), but I didn't set any validator on observableArray itself.
If it is cascading effect, then why it doesn't appear in case on one invalid field?

Is there a way to get array without that effect? As I would say that array itself is fine for me, as it have proper length, etc.

[tomalec]

Same problem appears even in sipler case with required rule
http://jsfiddle.net/tomalec/RWza9/
and there is even bigger one.

When I have two fileds, empty by default, that requires value, errors count is equal to 2 (as desired),
but after I have filled both of them, the error count is still 1 ([null]).

[stlk]

I don't know if this behavior is desired, but I found a solution. To force validation.group to behave correctly you need to call observable instead of just passing it.

Using previous example:

ko.validation.group(self.rows()); // add parentheses 

[danjohnso]

I figured this out for anyone that comes across this. if your group is an observableArray, you need to just pass the unwrapped array as the group.

My app uses a validation function because I have groups attached to Tab objects, so I just check if the group coming in is an observable array and then call the observable in that scenario.

var TabValidation = function (tab) {
if (tab.IsValidatable) {
var group = tab.ValidationGroup;

            if (ko.isObservable(tab.ValidationGroup) && Object.prototype.toString.call(tab.ValidationGroup()) === '[object Array]') {
                group = tab.ValidationGroup();
            }

            var errors = ko.validation.group(group, { deep: true });
            tab.Errors(errors().length);
            errors.showAllMessages();
        }
    };

[crissdev]

The real problem is in collectErrors - this function is executed from a computed which creates dependencies on error and isValid properties. When any of the observables in the group is validated, validateObservable invokes setError or clearError thus triggering a change to error property then to isValid. This is why the computed returned by ko.validation.group is notified many times and with intermediary states.
The solution to this is to use peek for error property to prevent a dependency to be created - this will not break the existing functionality because isValid is set whenever error is set through setError or clearError.

    function collectErrors(array) {
        var errors = [];
        ko.utils.arrayForEach(array, function (observable) {
            if (!observable.isValid()) {
                // Use peek to prevent a dependency to 'error' property because it
                // changes before 'isValid' does. (Issue #99)
                errors.push(observable.error.peek());
            }
        });
        return errors;
    }

[crissdev]

Working example http://jsfiddle.net/tnj6u5fs/