I’ve been trying to install snapcraft in parallel with itself so that I can use snapcraft 7 alongside snapcraft 6.
Snapd refuses to install a parallel instance when you specify a channel:
$ snap install --channel 7.x/stable snapcraft snapcraft_7
error: a single snap name is needed to specify channel flags
Snapd refuses to install a classic snap in parallel:
$ snap install snapcraft snapcraft_7
error: This revision of snap "snapcraft_7" was published using classic
confinement and thus may perform arbitrary system changes outside of the
security sandbox that snaps are usually confined to, which may put your
system at risk.
If you understand and want to proceed, repeat the command including
--classic.
$ snap install --classic snapcraft snapcraft_7
error: cannot specify mode for multiple store snaps (only for one store snap or several local ones)