Docs: Describe the shape of post type, taxonomy and capability data

[swissspidy]

Documents the types of several values that are currently only described as array, stdClass or bool[], so their contents are visible both to anyone reading the docs and to static analysis. Docblock changes only, no behavior change.

Three of these look like genuine documentation bugs rather than gaps:

• get_taxonomy_labels() omits two labels its object always carries. _get_custom_object_labels() always sets name_admin_bar, and both label builders add menu_name to the defaults before merging. Core itself reads $taxonomy->labels->menu_name in wp-admin/menu.php. get_post_type_labels() documents menu_name, but not name_admin_bar, and not template_name either, which its own @since 6.6.0 line mentions.
• Labels that can be null are documented as string. WP_Post_Type::get_default_labels() and WP_Taxonomy::get_default_labels() are both typed (string|null)[][], and for eight taxonomy labels and one post type label the default really is null for one of the two hierarchies: popular_items on a hierarchical taxonomy, parent_item_colon on a non-hierarchical post type, and so on. Those become string|null.
• get_registered_settings() omits the group key. register_setting() always stores it through its defaults. The same docblock, and register_setting() itself, describe sanitize_callback as callable when its default is null.

Alongside those:

• get_post_type_labels() describes its return value with the same hash notation get_taxonomy_labels() already uses, instead of a prose list, so the two read alike.
• WP_Taxonomy::$cap lists the four capabilities it holds, mirroring the capabilities argument of register_taxonomy(). WP_Post_Type::$cap gains a @see get_post_type_capabilities(), where its own list already lives.
• WP_User::$caps, WP_User::$allcaps and WP_Role::$capabilities are keyed by capability name, so array<string, bool> rather than bool[].

Verified with composer phpstan, at the configured level 5 with the existing baselines and reportUnmatchedIgnoredErrors: true: no new errors, and no baseline drift.

Trac ticket: https://core.trac.wordpress.org/ticket/65817

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Used for: comparing the existing docblocks against the code that builds these objects, and drafting the documentation changes in this pull request.

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[westonruter]

I really want to figure out a way to type this.

[westonruter]

I think we should add the PHPStan type as well, as otherwise this cannot help with static analysis.

[westonruter]

Correcting the WP dev docs is good, but what would be greater is adding the PHPStan types. Or, I wonder if we could add an extension that would teach PHPStan how to interpret the WordPress flavor of phpdoc.

[swissspidy]

Good point. To a degree it's possible. Normally the WP flavor is transformed into PHPStan types in the wordpress-stubs project, that's how I use it. But adding PHPStan types directly would help both internally and externally. And an extension could be reusable too and help reduce docs duplication.