cool - I will indeed rework the upcoming dpkg-source class to use this. 
Thanks a bunch for the hint!

On Thursday, November 22, 2018 at 10:38:21 AM UTC+1, Henning Schild wrote:
>
> From: Henning Schild <hen...@hennsch.de <javascript:>> 
>
> Instead of using "su" use "chroot --userspec". That should also be the 
> pattern for other chroot users that do not need root. i.e. kernel build 
> and upcoming "apt-get source" fetcher. 
> This way we can skip all the chowning we had/have to do otherwise. 
>
> Signed-off-by: Henning Schild <henning...@siemens.com <javascript:>> 
>