Update the `wp_print_scripts` filter in default-filters.php to be an action

[davidbaumwald]

Original reporter is @cybr.

In src/wp-includes/default-filters.php, wp_print_scripts is added as a filter, but is actually an action. Underneath they are the same, but this should be updated to use the correct alias with add_action.

This would be a great first bug for a newer contributor, so marking as such.

[Cybr]

Action 'customize_controls_print_styles' has the same issue, only a few lines down.

[abhi3315]

I am a first-time contributor to the WordPress core. I believe this issue will be good to get started.

I am working to create a patch for this issue.

Trac ticket: 58665

• Added add_action for the below action hooks:
  • customize_controls_print_styles
  • wp_print_scripts

[davidbaumwald]

In 56140:

Default Filters: Correct hook type for wp_print_scripts and customize_controls_print_styles.

Props Cybr, bhi3315.
Fixes #58665.

Thanks for the PR @abhi3315! I was able to merge this into Core in https://core.trac.wordpress.org/changeset/56140, so this will be a part of the 6.3 release!

[davidbaumwald]

@stevenlinx I don't think this should be added to the field guide. That's usually reserved for larger changes that Devs should be aware of.

In this case, this isn't adding or changing the root hooks. The do_actions have been in place forever. This change simply corrected the hook type in a place where Core was hooking in itself.

[stevenlinx]

I'm indifferent to whether the field guide includes it.

My rational to add the label was that it's been modified.

Per "Publishing the Field Guide" | Core Handbook:
​https://make.wordpress.org/core/handbook/tutorials/publishing-the-field-guide/
"Ideally all new and modified hooks are noted in a bulleted list (e.g., 4.8)."

If you look at v4.8 guide
​https://make.wordpress.org/core/2017/05/26/wordpress-4-8-field-guide/

There is a "Modified Filter Hooks" section at the bottom.

In my current draft guide, I noted it as "The filter hooks wp_print_scripts and customize_controls_print_styles have been fixed to become action hooks."
(my understanding: a filter expects a return value, action does not; so a third party developer may need to change their code? if their code no longer need to expect a return value)

In this case, the original code was wrong to begin with, so it's a good thing to let the developers know the code have been fixed?

As the owner of the ticket, if you feel it's insignificant, then feel free to remove the label.

[davidbaumwald]

@stevenlinx Thanks for the context. However, the changes there are to the apply_filters and do_action sides of each hook. In this ticket, these were not changed. This changed two instances of add_filter to add_action where Core was hooking into itself. As such, there's nothing to note for developers as the name/signature of the hooks themselves remain unchanged.