Empty field values when not renderable

Not sure if this is the right approach, but we fixed it in our setup with the attached patch.
We would love to discuss this if there are other ways to fix this.

Hi Tim,

Your proposal is interesting. It works only for layouts but maybe it is enough and we don't need a more generic solution. For exeample, this issue is about layouts: 🐛 Drupal entities containing optional or multiple fields do not render patterns correctly Closed: won't fix

However, you are dealing only with empty #cache and #weight values:

['#cache' => [], '#weight' => NULL];

We need to deal also with non empty #cache values, and bubble them.keys

Not sure of the issue, but I've you try simply using the |render filter, like this :
{% if description|render %}

{{ description }}

{% endif %}

{% if description.0 is not empty %}<p class="fr-tile__desc">{{ description }}</p>{% endif %}

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

Hey Pierre,

I did not have the full context there on what could all be possible, so just made something so our team had something working.
Happy to discuss this approach and see if we get there with this approach or if it does something different.

I understand what you say with none empty #cache and maybe non empty #weight values.
You have an idea on how to bubble the cache keys?

@fb-multimedia and @ravi kant Those are not solutions as you can read in the original D.O. core issue.

@Tim-Diels
You're right, sorry.

Let's move this to 2.x now the development rbanch is open and active.

However, not in the scope of 2.0.0, so let's target 2.1.x

If the issue is found only in Layout Builder, we can do the fix in:

• https://www.drupal.org/project/ui_patterns_layout_builder → for UI Patterns 1.x
• ui_patterns_layout for UI Patterns 2.x

We also have this weird behaviour with empty markup:

  $variables['test'] =  [
    "#markup" => "",
  ];

{{ test ? "true" : "false" }}

Result:
true

Maybe we have to create an issue for Drupal Core.

Following

Target: 1.9

(let's create another ticket for 2.x)

Let's do it in 2.x finally

This is actually a SDC Issue. We are doing an ugly workaround here.

The main problem is still there is no real good method to check if the array is empty. The way described in the issue only works in a list of cases but there will be cases where which it doesn't work.

Maybe we switch the scope of this issue and only checking slots as fields in layout builder and with field formatter and nothing more. Because this array guessing if it is maybe empty works only sometimes.

Yes, it is a SDC issue, and Core team has the same worries as you: 🐛 SDC: Make empty render arrays evaluate to false in component templates Active

But it is also doable at a UIP2 level IMHO, and we can propose to move the fix to Core later

I implemented a empty check for render arrays for 1 slots.

I have added a few coding related comments, but my main concern is the logic being located in ComponentElementBuilder instead of ComponentElementAlter.

Because those 2 methods are only called from ComponentElementAlter for now, and we want to keep the calls here so all renderables will benefit from the logic instead of only the renderables built from ComponentElementBuilder .

Am I missing something?

I moved the stuff to ComponentElementAlter and made them protected. My initial idea was that maybe other consumers using this method before they provide the slot. For example if layout builder surround the slots with an container. But it is better to make it first protected and if there is a need we introduce it as an API.

That looks great. I will add a few comments for the future us, and I will merge.

I am doing a big rebase because 📌 [2.0.0-alpha3] Replace component() function by native Twig mechanisms? Active was merged before.

With this rebase, I may lose this MR comment from @duaelfr:

suggestion (perfs): merge metadata without using the renderer service by directly calling BubbleableMetadata::createFromRenderArray, BubbleableMetadata::merge and BubbleableMetadata::applyTo methods

Christian, have you seen this comment?

I checked BubbleableMetadata right now. There is only BubbleableMetadata::createFromRenderArray static. All other methods are not static. Do I miss somtehing?

@christian.wiedemann Sorry my comment was unclear.
The idea was to replicate the feature of \Drupal\Core\Render\Renderer::mergeBubbleableMetadata() without calling the renderer service, which is not needed here.
I added a commit to the MR to illustrate.