is-active/deactivate should also check the "active_plugins" option

[kkmuffme]

Bug Report

• Yes, I reviewed the contribution guidelines.
• Yes, more specifically, I reviewed the guidelines on how to write clear bug reports.

Describe the current, buggy behavior

When a plugin file/directory is removed by the user (and not by WP), the "active_plugins" option will still contain that plugin.
Various plugins (and WP core?) use this "active_plugins" option for dependency checks, loading of compatibitility data,...

However wp plugin is-active and wp plugin deactivate will report that the plugin isn't active/the plugin could not be found.

WP core has a function https://developer.wordpress.org/reference/functions/validate_active_plugins/ to update this option (and deactivate all those not found ones), however it will deactivate ALL of those plugins, not necessarily only the one passed to CLI. However it's trivial copy and port that to CLI.

Describe how other contributors can replicate this bug

wp plugin activate whatever
rm -rf wp-content/plugins/whatever
wp plugin deactivate whatever
wp eval "echo array_values( preg_grep( '#^whatever#', get_option( 'active_plugins' ) ) )[0];"

Describe what you would expect as the correct outcome

is-active and deactivate should deactivate the plugin if it's still in active_plugins but the directory does not exist.

Provide a possible solution

See validate_active_plugins()

[swissspidy]

Updating wp plugin deactivate sounds reasonable at first glance, but we shouldn't change is-active to make destructive actions. That sounds very unexpected when you just want to check the status.

[swissspidy]

What about wp plugin is-active emitting a warning if the plugin does not exist but is still in the active_plugins option?