Sorting by a draggable view causes duplicates if multiple sorts are called 'weight'

Here's the attached patch file. Basically in the draggable_views_join_handler.inc file where we're getting the sort field it's like this

$view_query->view->sort['weight']->options['draggableviews_setting_view']

However, using the key "weight" is unreliable because other modules or fields might be named weight. For example, the taxonomy weight field, which is what was causing the break in my environment. I've rewritten this file to more intelligently determine exactly which field is the draggable views field instead of just relying on "weight".

Put a bunch of taxonomy terms and nodes in a site, then order a view by both taxonomy term weight and draggable views weight.

Since both fields are named "weight", conflicts will occur because draggable views doesn't know which "weight" field to use in the handler.

Sorry if I'm being unclear. The issue can be seen most clearly in the code itself. This is in draggable_views_join_handler.inc

  $view_query->view->sort['weight']->options['draggableviews_setting_view']

Lines like this, where we're selecting a member of the $view_query->view->sort array using the key ['weight'], is where the problem lies. ['weight'] is a vague selector that can match multiple sort criteria, not just the draggable views weight sort. If you add "Taxonomy: Weight" to your sort criteria first, then "Taxonomy: Weight" gets the ['weight'] key in the sort array and draggable views gets the key ['weight_1'].

It's the fact that we're using the vague selector ['weight'] to determine which field is the draggable field that causes a lot of errors like duplicates.

Attached is a view for reference. Import it, then put a dsm() or some kind of variable dump in draggable_views_join_handler.inc right above line 31

      dsm($view_query->view->sort);
      if (!empty($view_query->view->sort['weight']->options['draggableviews_setting_view'])) {

You'll see in the variable dump that the draggable views handler has the key ['weight_1'] but the if statement is using the key ['weight'] (which is the taxonomy weight sort), which is causing the view to bug out and fail in weird ways (one of which is creating duplicates).

The solution proposed in the patch is to find the draggable sort field's key in a more robust way instead of just $view_query->view->sort['weight'] (which will fail).