setting location with trailing hash causes $digest() iterations reached exception

[patrickdyson]

in angular 1.2.23
to get the browser to scroll to an anchor tag (using the $anchorScroll service), we set $location.hash('foo'). When an event triggers (like a mouseclick), the digest exceptions reached triggers with a message like

Error: [$rootScope:infdig] 10 $digest() iterations reached. Aborting!
Watchers fired in the last 5 iterations: [["fn: $locationWatch; newVal: 152; oldVal: 151"],["fn: $locationWatch; newVal: 153; oldVal: 152"],["fn: $locationWatch; newVal: 154; oldVal: 153"],["fn: $locationWatch; newVal: 155; oldVal: 154"],["fn: $locationWatch; newVal: 156; oldVal: 155"]]
http://errors.angularjs.org/1.2.23/$rootScope/infdig?p0=10&p1=%5B%5B%22fn%3…n%3A%20%24locationWatch%3B%20newVal%3A%20156%3B%20oldVal%3A%20155%22%5D%5D

The root cause is the location Watch looking at oldUrl != $location.absUrl() to determine a change but absUrl returns the URL without the trailing hash, i.e.

oldUrl = $browser.url() = http://host.com/Dashboard#!/#foo"
$location.absUrl() = "http://host.com/Dashboard#!/"

var changeCounter = 0;
$rootScope.$watch(function $locationWatch() {
  var oldUrl = $browser.url();
  var currentReplace = $location.$$replace;

  if (!changeCounter || oldUrl != $location.absUrl()) {
    changeCounter++;
    $rootScope.$evalAsync(function() {
      if ($rootScope.$broadcast('$locationChangeStart', $location.absUrl(), oldUrl).
          defaultPrevented) {
        $location.$$parse(oldUrl);
      } else {
        $browser.url($location.absUrl(), currentReplace);
        afterLocationChange(oldUrl);
      }
    });
  }
  $location.$$replace = false;

  return changeCounter;
});

[btford]

Can you please provide a reproduction via jsbin, plnkr.co or jsfiddle. This saves us a lot of time. Thanks!

[patrickdyson]

We have not been able to reproduce it on plnkr yet. By going back to 1.2.21 with our app, the problems go away. We have seen several instances and it was a bit confusing, but they all have the same core issue that the code in $browser.url has a cached version of the current url (lastBrowserUrl), but location.href is different.

So $location.absUrl gets set to /bar, locationWatch fires, it checks browser.url which returns location.href (which is /foo), sees that it is different, calls browser.url(/bar). That checks lastBrowserUrl, but that is already /bar, so it does nothing. That then iterates until the iteration limit is reached.

We will try to create a simple reproducible case but I'm not hopeful. I can give access to a dev server that does make the issue happen reliably, lmk if that is interesting.

hmm, this has very similar symptoms #6976

[patrickdyson]

1.2.24 fixes our issue, appears that the bug fix for #6976 gets our issue also. I will close this as a dup of that one