When a region has a region_class set to empty, it nevertheless gets an empty Attributes object.
For example, this is a default content node export:
regions_classes:
sidebar: ''
highlighted: form-highlighted
highlighted_bottom: ''
main: ''
content: ''
The saved value for highlighted_bottom is '' and the region has no blocks placed, but the current code will still create the content.region with an Attributes object only with an empty '' class.
This means any check on twig will fail and output the region, even if empty. Example:
{% if content.highlighted_bottom %}
<h1>I will render no matter the emptyness of the region</h1>
{{ content.highlighted_bottom }}
</div>
Perform an additional check to discern if the region_class is actually populated.
Needs review
2.1
Code
Created a MR with the same solution than the region_attributes: an empty() check.
I'm uploading a patch based on the MR to apply safety from composer