ngAria disables tabbing to a radio set when no default value selected

[OverZealous]

• Overview of the Issue - When a radio set is configured with no default selected value (ie: the value starts out as undefined), all the radio buttons will have their tabindex set to -1, making it impossible to tab to the radio set.
• Motivation for or Use Case - This makes it difficult to use a normal radio set for focus when you don't want to preselect the value for the user.
• Angular Version - 1.4.1
• Browsers and Operating System - Tested on FF39 on Mac OS X 10.10.4
• Reproduce the Error - View on Plunkr
• Related Issues - A partial attempt to fix this was issue ngAria - incorrect "aria-checked" and "tabindex" applied to checkbox/radio #10212
• Suggest a Fix - I'm not sure what the right solution here is. Some ideas:
  • I don't know what the purpose of setting the tabindex to -1 is, if it's not critical, it probably should be removed.
  • Another option would be to find the entire set of radios with a matching name, and if none are selected, then all should be active, otherwise only the selected on is active.

[OverZealous]

Note: I added tabindex="0" to all of the radios, and tabbing worked as expected (it only tabbed to the selected radio once one was checked), so it seems like there is no good reason to set tabindex to anything other than 0 if the input is enabled.

[marcysutton]

ngAria shouldn't be adding tabindex to radio inputs at all–I will be sure to account for that in #12262.

[marcysutton]

Closing as duplicate of #11500.

[mmaday]

@marcysutton This problem is still happening in Angular 1.4.7. See the plunkr at http://plnkr.co/edit/f58uFdkxKNsHFcbIN1nm?p=preview. The problematic code is in the aria ngModel directive:

          function getRadioReaction() {
            if (needsTabIndex) {
              needsTabIndex = false;
              return function ngAriaRadioReaction(newVal) {
                var boolVal = (attr.value == ngModel.$viewValue);
                elem.attr('aria-checked', boolVal);
                elem.attr('tabindex', 0 - !boolVal);
              };

[gkalpak]

Seems like a valid issue. WDYT, @marcysutton ?

[marcysutton]

Totally a bug! ngAria shouldn't be adding tabindex to native inputs at all. That should have gone into #11500.

[marcysutton]

@gkalpak I wrote a test that reproduced the problem and got a fix submitted in #13095.