[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 matches the author ID stored on the post, without looking the user up, so the posts of a deleted user are still found by the author.id their output returns. A slug that names no user gives the empty result, as before, 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 }
}

A slug 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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Props jorgefilipecosta, gziolo.

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[gziolo]

Thank you, Jorge! The author object uses the same keys as the author field in the output, so the input and output now fit together well. Approving.

Before this is committed, please look at the two inline comments. They are about the same thing: the id filter also matches posts of a deleted user, but the schema description and a code comment say it matches no post. The behavior is good, only the text needs a fix, plus one test to keep the behavior.

[gziolo]

This comment is not correct for IDs. WP_Query matches the author ID saved on the post (the post_author column). It does not check if the user exists. If a user is deleted, their posts can keep the old ID, and { id: <old ID> } still returns them.

I think this is good behavior. The output still returns author.id for these posts, so the caller can use it as a filter. Let's only fix the comment:

Suggested change

	/*
	* An author filter that names no user matches no post, like IDs and slugs that name
	* no post, rather than failing the query. An `id` that names no user needs no lookup:
	* the query matches no post on its own.
	*/
	/*
	* A slug that names no user, or an ID and a slug that name different users, match no
	* post, like IDs and slugs that name no post, rather than failing the query. An `id` is
	* not looked up: the query matches the stored author ID, so the posts of a deleted user
	* still match it.
	*/

Could you also add a test? Create a post with post_author => REST_TESTS_IMPOSSIBLY_HIGH_NUMBER (like in test_author_object_describes_the_author()), then check that { id: REST_TESTS_IMPOSSIBLY_HIGH_NUMBER } returns it.

[jorgefilipecosta]

Hi @gziolo, thank you. The suggestion was applied, and test_author_filter_by_id_matches_the_posts_of_a_deleted_user() now checks that { id: REST_TESTS_IMPOSSIBLY_HIGH_NUMBER } returns the post with that stored author ID.

[gziolo]

Same problem as above, but this text is part of the public schema. Agents and MCP clients read it, so it should match the real behavior.

Suggested change

	'description' => __( 'Filter by the post author, given as the `id` or the `slug` the `author` field of a post returns. An ID or slug that names no user, or an ID and a slug that name different users, match no post. Only supported for post types that support authors.' ),
	'description' => __( 'Filter by the post author, given as the `id` or the `slug` the `author` field of a post returns. An `id` matches the author ID stored on the post, even when that user no longer exists. A `slug` that names no user, or an `id` and a `slug` that name different users, match no post. Only supported for post types that support authors.' ),

Please also update the 'ID' case in data_author_filters_that_name_no_user(). It passes only because no post has that ID. The new test above covers IDs better, so this case can go.

[jorgefilipecosta]

Hi @gziolo, thank you. The suggestion was applied, and the ID case was dropped: the test now covers the slug only, as test_author_filter_with_a_slug_that_names_no_user_matches_no_post().

[jorgefilipecosta]

Committed at e29e51d.