Styleguide causes fatal if some image style needs the image dimensions

Dave Reid → made their first commit to this issue’s fork.

I'm not able to replicate the issue, I have a site using Focal Point and I'm not seeing any fatal errors on the current 2.x branch.

(I'll try to find time to reproduce that tomorrow. In the meantime I rerolled the MR)

@Dave Reid Thank you for trying to reproduce. I found out that this has been fixed in the Focal point module by "chance" (D10 compatibility issue)
https://git.drupalcode.org/project/focal_point/-/commit/d6f8823#035115c4...

I don't know if other image style extension modules have the same kind of issue or not but it seem safer to me to assume it could.
After digging a bit I now see two options:

1. Merge this MR as it is because it's kind of doing the same that Core does in template_preprocess_image_style_preview()
2. Use the '#theme' => 'image_style_preview' in your module instead of creating a custom preview so you don't have to worry about it anymore

What do you think?

I'm torn about this because I think not providing the height and width is generally the default behavior for theme_image_style. There are several usages in core itself that do not do this:

\Drupal\media\MediaListBuilder::buildRow()

        $row['thumbnail']['data'] = [
          '#theme' => 'image_style',
          '#style_name' => 'thumbnail',
          '#uri' => $thumbnail_uri,
          '#height' => 50,
          // Note no #width attribute provided.
        ];

\Drupal\media_library\Form\AddFormBase::buildEntityFormElement()

      $element['preview']['thumbnail'] = [
        '#theme' => 'image_style',
        '#style_name' => 'media_library',
        '#uri' => $thumbnail_uri,
      ];

I also find many uses of this in contrib as well. I am tempted to say this was a bug in Focal Point that was resolved and not here, as this seems to be a fairly common use without providing them.

No need to keep that open :)
Thanks Dave!