Documentation for add_meta_boxes hook is incorrect

[johnbillion]

The documentation for the add_meta_boxes hook states that the $post parameter is a WP_Post object. This is incorrect because the object can be any type. On the comment editing screen for example, this parameter is a WP_Comment object.

[danieltj]

The add_meta_boxes hook doesn't have a parameter for a $post, at least not in function I found. Am I looking at the wrong one? I didn't see anything that referenced posts.

Reference: https://core.trac.wordpress.org/browser/tags/4.9/src/wp-admin/includes/template.php#L886

[danieltj]

Sorry @SergeyBiryukov my comment overwrote the changes. I reverted back.

[SergeyBiryukov]

Replying to danieltj:

The add_meta_boxes hook doesn't have a parameter for a $post, at least not in function I found. Am I looking at the wrong one? I didn't see anything that referenced posts.

It's about the add_meta_boxes filter, not the add_meta_box() function :) There are 3 instances of the hook:

• https://core.trac.wordpress.org/browser/tags/4.9/src/wp-admin/edit-form-advanced.php#L326
• https://core.trac.wordpress.org/browser/tags/4.9/src/wp-admin/edit-form-comment.php#L175
• https://core.trac.wordpress.org/browser/tags/4.9/src/wp-admin/edit-link-form.php#L32

[danieltj]

Replying to SergeyBiryukov:

Replying to danieltj:

The add_meta_boxes hook doesn't have a parameter for a $post, at least not in function I found. Am I looking at the wrong one? I didn't see anything that referenced posts.

It's about the add_meta_boxes filter, not the add_meta_box() function :) There are 3 instances of the hook:
[...]

Ah, thank you for pointing that out. Was very confused when I saw the docs.

I'll take a look.

[danieltj]

Patch to include all three object types.

[SergeyBiryukov]

In 42796:

Docs: Improve documentation for add_meta_boxes and do_meta_boxes actions.

Props danieltj, johnbillion, SergeyBiryukov.
Fixes #43229.