Ensure Drupal 11.4 fonts API compatibility in dxpr_theme.libraries.yml

[jjroelofs]

Summary

Drupal core 11.4 introduced a fonts: key in libraries.yml for native font preloading (core issue #3366561, change record https://www.drupal.org/node/3585574). A user reported PHP warnings when running Drupal 11.4.1 with the DXPR suite, including a grep result showing fonts: entries in dxpr_theme.libraries.yml at lines 211 and 219.

The current 8.x branch does not contain any fonts: entries in dxpr_theme.libraries.yml, so the user's installation appears to have been modified (possibly to mirror the font preloading entries added to dxpr_builder in PR dxpr/dxpr_builder#4745).

This issue tracks two concerns:

1. If fonts: entries are added to dxpr_theme in the future, they must use YAML mapping syntax (path: {preload: true}) rather than list syntax (- path). List syntax produces integer keys that cause "Undefined array key preload" errors in HtmlResponseAttachmentsProcessor. See dxpr/dxpr_builder#4775 for the equivalent fix in dxpr_builder.

2. The existing custom font preloading code in features/sooper-fonts/fonts-theme-settings-controller.inc uses #attached['html_head'] to add preload link tags. This approach is independent of the fonts: API and should continue to work, but should be evaluated for potential migration to the core fonts API in a future release.

Steps to reproduce

1. Install Drupal 11.4.1 with dxpr_theme
2. Add fonts: entries using YAML list syntax to dxpr_theme.libraries.yml (e.g., fonts:\n - path/to/font.woff2)
3. Clear caches and load any page

What is the current bug behavior?

PHP warning: Undefined array key "preload" in Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments() (line 132).

What is the expected correct behavior?

No PHP warnings. Font entries should use the mapping syntax expected by Drupal 11.4:

fonts:
  path/to/font.woff2:
    preload: true

Relevant logs and/or screenshots

Error from user report:

Warning: Undefined array key "preload" in Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments() (line 132 of core/lib/Drupal/Core/Render/HtmlResponseAttachmentsProcessor.php).

Possible fixes

If fonts: entries are needed, use mapping syntax with explicit preload flag. See dxpr/dxpr_builder#4776 for the equivalent fix pattern.

[jjroelofs]

Closing: the dxpr_theme 8.1.3 release on Drupal.org uses the correct YAML mapping syntax (path: {preload: true}) for its fonts: entries. The PHP warning Chris reported is caused by dxpr_builder's list-syntax entries, not dxpr_theme. See dxpr/dxpr_builder#4775.

Separate concern: the font.league-gothic and font.chunk-five libraries from the 8.1.3 release are missing from the GitHub 8.x branch; a follow-up issue will track syncing those.