Template Types in patterns not working

[bgardner]

Description

Using the following code in my patterns to make certain patterns available for creation of templates:

<?php
/**
 * Title: Post content with gradient cover
 * Slug: powder/template-single-gradient-cover
 * Categories: powder-template
 * Template Types: single
 */
?>

With WordPress 6.4.2, here is a screenshot taken after following the steps below:

With WordPress 6.4.2 and Gutenberg 17.6.0 RC1 active, here is a screenshot taken after following the steps below:

I have two patterns in my theme which use * Template Types: single.

Step-by-step reproduction instructions

1. Go to Editor > Templates > Add New Template > Single item: Post
2. Select All Posts
3. See available templates.

Screenshots, screen recording, code snippet

No response

Environment info

WordPress 6.4.2
Gutenberg 17.6.0 RC1

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[bgardner]

I can also replicate this issue with the TT4 default theme.

[bgardner]

Also worth noting, this issue does NOT exist with Gutenberg 17.5.2 active:

[colorful-tones]

I'm sleuthing on this now to see where code was introduced to cause this regression.

Steps for testing and verifying:

1. Open Site Editor > Templates > Add New Template: 'Single item: Post' > All Posts
2. The 'Choose a Pattern' modal should pop up and with TT4 activated there should be two patterns available.

Before	After (w/ regression)

[colorful-tones]

Something was introduced in #57999 that caused this regression. Maybe @ellatrix might have some insight. I'm now peeking at the code that was altered in the PR.

[colorful-tones]

I suspect that one of the two patterns in our testing scenario comes from the WP core and not the Twenty Twenty-Four theme. There is only one pattern in the Twenty Twenty-Four theme that has a single template target Template Types: posts, single in twentytwentyfour/patterns/template-single-portfolio.php. The other pattern is probably not a pattern per se, and likely showing the twentytwentyfour/templates/single.html?

[ellatrix]

Does this fix the problem by any chance? #58661

[ellatrix]

Thanks for providing minimal steps to reproduce. I indeed see two patterns for 17.5 but online 1 in trunk and even with that branch. I'll investigate further.

[colorful-tones]

Thanks @ellatrix for digging in. I meant to dig on the code but did not make it that far. I’m happy to test any follow up.