[jorgefilipecosta]

Follow up to https://core.trac.wordpress.org/changeset/64388. Builds on #14643, whose commit is included here until it lands.

What

• The where.author_slug filter of core/content-query is replaced by a where.author object with the optional properties id and slug, the keys the author field of a post returns.
• An ID or a slug that names no user matches no post and gives the empty result, as an unknown slug already does, and so do an ID and a slug that name different users.
• A value that is not an object with an id or a slug, an id that is not a positive integer, and a slug that is not a non-empty string are rejected as invalid filters, with where[author], where[author][id] and where[author][slug] as the parameter.

Why

• A post's author comes back as author: { id, name, slug }, so a caller can now pass that object back as the filter instead of translating it to a differently named string. @gziolo asked for this shape in Abilities API: Return the empty result for an author_slug that names no user #14643 (comment).
• The REST API posts collection filters by author ID; the ability only took a slug. An ID needs no user lookup.

How

• The input schema describes author as an object with additionalProperties: false, minProperties: 1, id (integer, minimum 1) and slug (string, minLength 1), in the position author_slug had.
• The execute callback checks the filter in order: post type support, object shape, id through the existing integer parsing (0 fails closed, since WP_Query reads author => 0 as no author filter), then slug looked up as given. The query argument stays a single author user ID.
• Descriptions and docblocks that named author_slug now name author.
• Tests: the existing author_slug tests are converted, with data providers for the invalid shapes, IDs and slugs, the ID-and-slug combinations, filtering by ID, and the schema shape.

Example input, filtering the posts by their author's slug:

{
  "where": {
    "type": "post",
    "author": { "slug": "cq_author" }
  },
  "fields": [ "id", "title", "author" ]
}

The same author can be given by ID, "author": { "id": 3 }, or by both, "author": { "id": 3, "slug": "cq_author" }. The run endpoint takes the input as query arguments:

wp.apiFetch( {
	path: '/wp-abilities/v1/abilities/core/content-query/run?input[where][type]=post&input[where][author][slug]=cq_author&input[fields][]=id&input[fields][]=title&input[fields][]=author',
} );

Example output:

{
  "items": [
    {
      "id": 7,
      "title": { "raw": "Ann published", "rendered": "Ann published" },
      "author": { "id": 3, "name": "Ann Author", "slug": "cq_author" }
    }
  ],
  "pagination": { "total": 1, "total_pages": 1 }
}

An author that names no user, "author": { "slug": "nobody-here" }, or an ID and a slug naming different users, gives the empty result:

{ "items": [], "pagination": { "total": 0, "total_pages": 0 } }

The change was drafted with AI assistance and reviewed by me.

Trac ticket: https://core.trac.wordpress.org/ticket/66268

Testing

Verify unit tests are passing:

npm run test:php -- --filter author

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