EntityEmbedDialog causes undefined index notice if no embed display settings are presented to the user

Recently we changed the name of the attribute: #2760801: Rename data-entity-embed-settings attribute.

I see that Lightning is hard-coding some settings in lightning_media_form_entity_embed_dialog_alter(). I suspect that this is where error comes from.

I can't reproduce this on Lightning 8.x-1.x, unfortunately...I followed the steps in the failing test exactly, but no dice.

We can definitely reproduce this. It looks like a little more than fixing the hard-coded settings, but that's the crux. Thanks slashrsm.

I have traced the problem, and it's not actually Lightning's fault. (I know this partially because I traced it, and partially because I completely disabled the form_alter hook that @slashrsm mentioned and the problem still occurred.)

The problem is that it's very possible for nothing to be present in the attributes section of the Entity Embed dialog form. (In Lightning's case, it's because only one view mode is allowed for the media_browser embed button, so the select list for picking a view mode is never displayed.) The trouble is in EntityEmbedDialog::submitEmbedStep() -- line 735 -- which assumes that attributes[data-entity-embed-display-settings] is always present in the form (it uses the ?: operator, which emits an undefined index notice). It needs to do an isset() check or something similar.

I saw this error in my logs. This works for me.

+++ b/src/Form/EntityEmbedDialog.php
@@ -575,7 +575,7 @@ class EntityEmbedDialog extends FormBase {
+    $plugin_settings = !empty($entity_element['data-entity-embed-display-settings']) ?: array();

I don't think the ?: syntax works with a function call which returns a boolean, because we want to actually return the value.

Oh, right. Here is a new version.

Looks good to me.

Committed. Thank you all. Assuming Lightning will do its stuff in a separate issue so closing.