One media reference field for the episode audio

Problem/Motivation

The podcast episode carried two separate audio fields: field_audio, a local file upload, and field_audio_url, a link. An editor had to choose between them with nothing saying which one the page would render, and the two were bound to two separate components in the Canvas full template, one of which rendered empty on every episode.

Drupal already has a well understood pattern for exactly this: a single media reference field, where the editor picks the bundle from the media library, the way Video and Remote video already work.

Steps to reproduce

1. Install a Varbase Starter site on Varbase 11.
2. Apply the Varbase Podcasts Base recipe from 1.0.x-dev.
3. Go to /node/add/podcast. The form offers two audio fields, Audio (a file upload) and Audio URL (a link), and nothing on the form says which one the episode page will render.
4. Fill in only Audio URL, save, and view the episode. The Canvas full template still renders the component bound to the file field, and it renders empty.

Proposed resolution

• field_audio becomes an entity reference to media, targeting the audio and remote_audio bundles.
• field_audio_url is removed, storage and instance.
• The default form display uses the Media Library widget.
• The full view display renders the referenced media with entity_reference_entity_view, so each bundle renders through its own media display: a local file gives an audio controls player, a remote one gives the provider's embed, without the node display needing to know which bundle it got.
• The Canvas node.podcast.full content template walks node to media to file for the local case, and drops the component that was bound to the removed link field.
• Test content gains an audio media entity, and all twelve episodes reference it.

Dependency

The remote_audio bundle comes from Varbase Media Base, issue #3624670. This issue's field config depends on media.type.remote_audio, so #3624670 has to land first.

Verification

Done on a fresh Drupal CMS plus Varbase Starter install:

• The recipe applies cleanly to a freshly installed Varbase Starter site.
• field_audio is entity_reference to media with target bundles audio,remote_audio, and field_audio_url is absent.
• The test-content recipe applies and all 12 episodes resolve to a real audio media entity, with no dangling references.
• The local audio media entity renders audio controls with a source pointing at varbase-example-episode.wav, type audio/wav, through its own default display.
• The Canvas template's media to file walk resolves to the right file URL.

Remaining tasks

Known limitation, not solved here: Canvas can only render a field through an SDC, and Vartheme BS5 ships no audio component. So inside the Canvas full template the local audio still renders through the video component (a video element in a 21:9 frame), and a remote-audio episode renders nothing there. A follow-up issue on Vartheme BS5 for a proper audio component is needed, alongside #3622961.

• ✅ File an issue
• ✅ Addition/Change/Update/Fix
• ✅ Testing to ensure no regression
• ❌ Automated unit/functional testing coverage
• ➖ Developer Documentation support
• ➖ User Guide Documentation support
• ➖ UX/UI designer responsibilities
• ➖ Accessibility and Readability
• ❌ Reviewed by a human
• ❌ Code review by maintainers
• ❌ Full testing and approval
• ❌ Credit contributors
• ❌ Review with the product owner
• ❌ Update Release Notes
• ❌ Release

User interface changes

• The episode form no longer offers two audio fields. It offers one Audio field with the Media Library widget, where the editor picks an Audio or a Remote audio media item.

API changes

• N/A

Data model changes

• field_audio on the Podcast content type changes from a file field to an entity reference to media, targeting the audio and remote_audio bundles.
• field_audio_url is removed from the Podcast content type, both the field instance and its storage.
• New dependency on media.type.remote_audio from Varbase Media Base.

Release notes snippet

• A podcast episode now carries one Audio field referencing a media item, so an editor picks an uploaded audio file or a remote one from the media library instead of choosing between a file field and a link field. The Audio URL field is removed. Remote audio comes from Varbase Media Base.