wp 5.1 broke some themes working perfectly before, cause found

[bufny]

In wp-settings.php from wp5.1 there are the following lines of code (not present before):

<?php

// Load the functions for the active theme, for both parent and child theme if applicable.
foreach ( wp_get_active_and_valid_themes() as $theme ) {
        if ( file_exists( $theme . '/functions.php' ) ) {
                include $theme . '/functions.php';
        }
}
unset( $theme );

If the active theme is using the $theme as a global variable things mess up. I don't know who should refactor this (the wp core team or the hundreds theme creators), but the name of the variable here is unfortunately chosen.

[TimothyBlynJacobs]

Thank you for the report bufny, we're already tracking this issue in #46313