I manage to broke the default theme in development and now could not access the administration interface nor could I change the theme via drush.
The way I broke the default theme is by changing the name of the theme inside yml files and folder and function names without disabling it first. After changing it back to default and flushing the cache this does not fix the error.
No matter what drush command is run the result is the same:
In ThemeHandler.php line 491: The theme my_theme does not exist.
Folder is there and all files are there but drush returns always this error.
I try to run:
drush config-set system.theme default bartik
but the result is the same.
Could I fix this some other way?