entity collector selector only shows bundle, not entity type and is thus ambiguous

You may wish to check out my patch over on this thread:
Improving usability - Name/machine name for relations instead of using the label (comment #12)

Duplicate to #1856210: Improving usability - Name/machine name for relations instead of using the label

Re-opening this issue since it really isn't a duplicate of #1856210. Copying my patch file here and renaming it so that it is applied in the correct place. Several comments in #1856210 apply here and are worth a read.

Also putting my patch here after stopping discussing it in #1856210: Improving usability - Name/machine name for relations instead of using the label.

Woops.

Some of the changes might not be needed.

-          $options["$entity_type:$entity_id"] = "$entity_bundle: " . entity_label($entity_type, $entity);
+          $bundle_label = _relation_get_bundle_label($entity_type, $entity_bundle);
+          $options["$entity_type:$entity_bundle:$entity_id"] = $bundle_label . ': ' . entity_label($entity_type, $entity);

It looks like $entity_bundle is not needed in option keys at all. As of now it's used in relation_entity_collector_validate:

+      // Get entity info from key ('{entity_type}:{entity_bundle}:{entity_id}').
+      $entity_info = explode(':', $entity_key);

Outside of that validate function there is no use for it. Yes, previously it was there as well but bundle information is not needed when endpoints are saved.

In addition to that I think the following would be more readable here.

list($entity_type, $entity_id) = explode(':', $entity_key);

Updated patch, changes from comment 7 applied.

committed