Can't register Block Templates for CPTs with an underscore "_" character in the key

[alexandrebuffet]

After several days of using the new Block Templates API, I’ve noticed that we can’t register a template for a CPT that has underscore "_" in its key, it displays the error "Template names must contain a namespace prefix. Example: my-pluginmy-custom-template".

For example, I have a plugin that declares a CPT "school_course" and if I declare its associated templates "my-pluginarchive-school_course" and/or "my-pluginsingle-school_course" I get the error.

This error seems to be displayed because the test on the template name via the RegEx "/^{[a-z0-9-]+\/\/[a-z0-9-]+$/" returns false in register method from WP_Block_Templates_Registry class.}

Related issue in Gutenberg: ​https://github.com/WordPress/gutenberg/issues/67066

[karthickmurugan]

Allow underscore in register_block_template function patch.

[karthickmurugan]

Hello all.,

The above patch fixes the underscore issue in register_block_type function. Please have a look at this video for clear explanation and testing before and after the fix.

​https://share.cleanshot.com/qknmwCwGjX5tBWbCdFX5

[alexandrebuffet]

Thanks @karthickmurugan, I tested your patch and it corrects the problem.

[ankitkumarshah]

Test Report

Description

This report validates whether the indicated patch works as expected.

Patch tested: https://core.trac.wordpress.org/attachment/ticket/62523/62523.patch

Environment

• WordPress: 6.7.1
• PHP: 8.1.29
• Server: nginx/1.16.0
• Database: mysqli (Server: 8.0.16 / Client: mysqlnd 8.1.29)
• Browser: Chrome 131.0.0.0
• OS: macOS
• Theme: Twenty Twenty-Five 1.0
• MU Plugins: None activated
• Plugins:
  • Test Reports 1.2.0

Actual Results

1. ✅ Issue resolved with patch.

Supplemental Artifacts

Before Patch

​https://utfs.io/f/TnWMEUzoUd85e63Opo59in4IP8W2ScxrkUYbqyg7DsGdaTzp

After Patch

​https://utfs.io/f/TnWMEUzoUd85ETTGOEgxzLduKa2yRBnh7lb60Gwq5Sgc9H8V

[oglekler]

@noisysocks can you please look at this one?

This ticket was discussed during the Test team triage session.

According to WPCS
"Files should be named descriptively using lowercase letters. Hyphens should separate words."
​https://developer.wordpress.org/coding-standards/wordpress-coding-standards/php/

From this, it looks like all underscores in post type names should be filtered to hyphens, but if we don't have it yet, it can make braking change, so, it looks like the best option is to allow underscores in the template names.

[karthickmurugan]

@poena - Can you please take a look at this patch and move forward. Thanks in advance.

[gaambo]

register_post_type uses sanitize_key to sanitize the post type key, which in turn uses the following regex pattern: /[^a-z0-9_\-]/ I would recommend, to use the same regex and also comment/document that this must be the same as in register_post_type/sanitize_key so that it works for all post types.
I don't think there should be any problems with file names, since the same works for existing .php templates in classic themes as well.