Potential fatal error when previewing Customizer drafts

[aaemnnosttv]

Bug Description

The theme customizer provides the ability to preview drafts using a special URL. While previewing, it is possible for Site Kit to raise an error such as the one below

PHP message: PHP Fatal error:  Uncaught Error: Call to undefined function Google\\Site_Kit\\Core\\Util\\get_plugin_data() in /.../google-site-kit/includes/Core/Util/Auto_Updates.php:105
Stack trace:
#0 /.../google-site-kit/includes/Core/Util/Auto_Updates.php(56): Google\\Site_Kit\\Core\\Util\\Auto_Updates::sitekit_forced_autoupdates_status()
#1 /.../google-site-kit/includes/Core/Authentication/Authentication.php(902): Google\\Site_Kit\\Core\\Util\\Auto_Updates::is_plugin_autoupdates_enabled()
#2 /.../google-site-kit/includes/Core/Util/Method_Proxy_Trait.php(25): Google\\Site_Kit\\Core\\Authentication\\Authentication->inline_js_base_data()
#3 /.../example.com/public_html/...', referer: https://example.com/wp-admin/customize.php?return=%2Fwp-admin%2Fthemes.php

This is because the WP core function get_plugin_data is not loaded in this specific scenario.

Steps to reproduce

1. Set up Site Kit
2. Enable a theme that supports the customizer, e.g. Twenty Twenty
3. Go into the customizer and make any change
4. Click the cog next to Publish and choose Save Draft
5. Follow the URL given to preview the draft
6. See error

Screenshots

Additional Context

Related support request
https://wordpress.org/support/topic/i-get-a-critical-error-but-only-through-customizer/

---

Do not alter or remove anything below. The following sections will be managed by moderators only.

Acceptance criteria

• No errors should be raised by Site Kit while previewing a customizer draft

Implementation Brief

• Update Auto_Updates::sitekit_forced_autoupdates_status to conditionally load wp-admin/includes/plugin.php if the get_plugin_data does not exist prior to calling

Test Coverage

• No changes necessary

QA Brief

• Follow the "Steps to reproduce" in the issue description.
• Verify that the reported error no longer occurs.

Changelog entry

• Fix error when previewing Customizer drafts.

[techanvil]

IB ✅

[wpdarren]

QA Update: ✅

Verified:

• Tested to ensure I could recreate the error message in the issue description on the latest release.
• On the develop branch, I followed the steps to reproduce and the reported error no longer occurs.

Screenshots