Permit unbounded per_page=-1 requests for Categories and Tags

[danielbachhuber]

Description

Permits requests of per_page=-1 to /wp/v2/categories and /wp/v2/tags in order to fetch all available items; updates corresponding Gutenberg components to fetch all items.

Fixes #5820
Fixes #4022
Related #6627 #6657
See #6180 (comment)

How has this been tested?

I generated 200 categories with:

wp term generate category --count=200

When I access the category selection UI, I see all 200 categories:

Similarly, when I insert a category block, I see all categories:

It also works with a custom taxonomy:

add_action( 'init', function(){
	register_taxonomy( 'section', array( 'post' ), array(
		'hierarchical' => true,
		'show_in_rest' => true,
		'rest_base'    => 'sections',
	));
});

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.

[danielbachhuber]

Going ahead and landing this. Happy to own any follow-up issues that come up.

[tofumatt]

I am away on holiday (in Japan, trying not to do too much work 😅) this week and next so couldn’t review, sorry about that.

Is it usual to land un-reviewed PRs? Doesn’t seem like this was sitting here that long. It is dangerous to land unreviewed code; little mistakes happen and peer review often catches them.

[tofumatt]

FWIW the code seems similar to other patches around this and is fine (with all the existing caveats about unbounded results, etc).

But I don’t think we should be landing unreviewed code.

[danielbachhuber]

Is it usual to land un-reviewed PRs?

Nope. I needed to be able to move on to #6761 though.

It is dangerous to land unreviewed code; little mistakes happen and peer review often catches them.

I agree. I'm willing to own any post-merge code review in a follow-up PR.