Connectors: plugin.file does not account for mu-plugins.

[peterwilsoncc]

Description

The connectors screen uses plugin.file to determine whether a Core connector should be displayed for an installed but inactive plugin. For plugins installed as mu-plugins, this can result in the connector not being displayed when the plugin is in use.

Connector registration should account for plugins activated via mu-plugins.

Follow up to #76909.

Step-by-step reproduction instructions

Note

I've created a PR to remove the Akismet connector for both the GB and wp-dev repos. If these have been merged you will need to use the commits below

1. Install WordPress trunk, I used WordPress/WordPress@67fe063
2. Install, build and activate Gutenberg. I used 309dfc2
3. Ensure the Akismet plugin is installed in the plugins directory but not activated
4. Visit Settings > Connectors
5. Observe Akismet is shown as an option
6. Move the plugins/akismet folder to mu-plugins/akismet
7. Add the one line file mu-plugins/a.php with the content require_once __DIR__ . '/akismet/akismet.php';
8. Reload Settings > Connectors
9. Observe that the Akismet option is not displayed, despite the plugin being active.

Screenshots, screen recording, code snippet

Installed as mu-plugin

Environment info

• WordPress: 7.1-alpha-62193
• PHP: 8.3.30
• Server: nginx/1.24.0
• Database: mysqli (Server: 8.0.44-0ubuntu0.24.04.2 / Client: mysqlnd 8.3.30)
• Browser: Firefox 149.0
• OS: macOS
• Theme: Twenty Twenty-Five 1.4
• MU Plugins:
  • Allow filtering of syncing frequencies in polling client #76517 Sync rates filters.
  • akm.php
  • auto-activate-plugins.php
  • query-monitor-file-mappings.php
  • _admin_bar_gb_status.php
• Plugins:
  • Gutenberg 22.9.0-rc.1
  • Query Monitor 3.20.2
  • Test Reports 1.2.1

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

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure

[jorgefilipecosta]

Thank you a lot for catching this issue @peterwilsoncc and providing guidance on #76994.