Comment # 11 on bug 1159195 from Jeff Kowalczyk

(In reply to Andreas Stieger from comment #8)
> Mounting tmpfs to (here) /var/tmp works around the issue.

Expanding on the workaround described by Andreas:

WSL will mount /var/tmp as tmpfs configured in /etc/fstab:

tmpfs /var/tmp tmpfs defaults 0 0

An alternate workaround is to persistently set the environment variable
ZYPPTMPDIR to a mounted tmpfs:

ZYPPTMPDIR=/mnt/zypptmp

with ZYPPTMPDIR preserved in calls to sudo:

cat /etc/sudoers.d/env-keep-zypptmpdir
Defaults env_keep += "ZYPPTMPDIR"