Drupal entities containing optional or multiple fields do not render patterns correctly

Hi Marc-Antoine,

There are 2 distinct topics in your ticket.

Looping on slots (fields) values

As you already know, it is the scope of ✨ Make the Twig loops safer Postponed and we hope it will be fixed upstream, at Twig level.

Testing if a render array is true or false

It is a huge issue in Drupal https://www.drupal.org/project/drupal/issues/953034 🌱 [meta] Themes improperly check renderable arrays when determining visibility Needs work a nightmare for some, but it was not a big deal with UI Patterns usually. However, your issue seems related to this, so let's investigate.

Nothing wrong with the component itself. And nothing wrong with ui_suite_dsfr. It is about the render API.

Let's do some tests with this slot:

{% if description %}<p class="fr-tile__desc">{{ description }}</p>{% endif %}

From https://git.drupalcode.org/project/ui_suite_dsfr/-/blob/1.0.x/templates/...

We expect description to be false.

Test 1: empty array

$variables['description'] = [];

OK: description is false, because in PHP an empty array is false

Test 2: non renderable properties

[
  "#cache" => [
    "contexts" => [
      "user.permissions"
    ],
    "tags" => [],
    "max-age" => -1
  ]
]

OK: description is false. i don't know which mechanism do that, but it works OK

Test 3: non renderable properties wrapped in a mapping

Layout Builder is sometimes wrapping the render array in a mapping where the key is the block UUID:

[
"cf124739-3274-41cc-829d-c3465ee4eaa5" => [
  "#cache" => [
    "contexts" => [
      "user.permissions"
    ],
    "tags" => [],
    "max-age" => -1
  ]
]
]

KO: description is true. it must be false because there are only non renderable properties here. it seems Drupal is only testing the first level

Marc-Antoine, you tested with Display Suite, so it was another wrapping with another key (the field name, i guess), but it was the same issue. What do you think about this?

Hi Pierre,
Yes, I reproduce test 4 (Test 4: non renderable properties wrapped in a mapping) with Display Suite / Display Suite Ui Patterns. But instead of having the uuid generated by Layout Builder, I have the machine name of the field.

This issue is not specific to DSFR and has been moved elsewhere: ✨ Empty field values when not renderable Active