datepicker - initDate getting updated when navigating control

[arcdev]

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Bug description: As the user navigates the datepicker control, the initDate is updated. This causes issues if you use the the current date of one datepicker as the initDate of another.

Also, note how the Start Date control itself doesn't change, but the model value does.

Expected: initDate is essentially readonly.

Link to minimally-working plunker that reproduces the issue:

https://plnkr.co/edit/tvelT5r6ho59zcPzPvIH?p=preview

Steps to reproduce the issue:

As noted in the Plunker, simply navigate forward or backward by month in the End Date datepicker and note how the Start Date value changes.

Version of Angular, UIBS, and Bootstrap

Angular: 1.6.1

UIBS: 2.5.0

Bootstrap: 3.3.7

[arcdev]

It seems the root cause is that activeDate is set to initDate and since this is a reference type object (Date), any updates to activeDate also update initDate. And if initDate is the scope/model value of another control, then that other control's scope/model value is also updated.

Maybe because it's a reference type the other control doesn't get a watch fired?

[arcdev]

I might recommend changing the init method to this:

  this.init = function(ngModelCtrl_) {
    ngModelCtrl = ngModelCtrl_;
    ngModelOptions = extractOptions(ngModelCtrl);

    if ($scope.datepickerOptions.initDate) {
      var newInitDate = dateParser.fromTimezone($scope.datepickerOptions.initDate, ngModelOptions.getOption('timezone')) || new Date();
      self.activeDate = angular.isDate(newInitDate) ? new Date(newInitDate.getTime()) : newInitDate;
      $scope.$watch('datepickerOptions.initDate', function(initDate) {
        if (initDate && (ngModelCtrl.$isEmpty(ngModelCtrl.$modelValue) || ngModelCtrl.$invalid)) {
          var updatedInitDate = dateParser.fromTimezone(initDate, ngModelOptions.getOption('timezone'));
          self.activeDate = angular.isDate(updatedInitDate) ? new Date(updatedInitDate.getTime()) : updatedInitDate;
          self.refreshView();
        }
      });
    } else {
      self.activeDate = new Date();
    }

    var date = ngModelCtrl.$modelValue ? new Date(ngModelCtrl.$modelValue) : new Date();
    this.activeDate = !isNaN(date) ?
      dateParser.fromTimezone(date, ngModelOptions.getOption('timezone')) :
      dateParser.fromTimezone(new Date(), ngModelOptions.getOption('timezone'));

    ngModelCtrl.$render = function() {
      self.render();
    };
  };

That way activeDate is always a copy rather than a reference.

[arcdev]

check out pull request https://github.com/angular-ui/bootstrap/pull/6638