angular/angular.js — pull request #9016 by tbosch (2014-09-10 17:26:04+00:00)
Title: fix(ngModel): don’t clear the model when an external validator failed

Calling `ctrl.$setValidity()` with a an error key that
does not belong to a validator in `ctrl.$validator` should
not result in setting the model to `undefined` on the next
input change. This bug was introduced in 1.3.0-beta.12.

Closes #8357
Fixes #8080