The theme editor does not work

[ntavares]

After the latest WP Core update, the theme editor is not working, if I try to edit any file it shows the following error: “Sorry, that file cannot be edited.”
We do comment “$file = wp_normalize_path( $file );” in the wp-includes/functions.php file and it works again with the same configuration (active plugins, active theme, etc.).
After calling the wp_normalize_path function, the $file no longer exists in $allowed_files. This in_array( $file, $allowed_files, true ) return false. I think it is due to the absolute path in windows with backslashes.

It will probably only happen on a Windows server.

[mukesh27]

Duplicate of #61488.