I'm generally imagining we'll get something like this in the Blueprint configuration:

Submodules: [ Yes! (Slower)         V ]
            [ Sort of?                ]
            [ No (Faster)             ]
          
     Clean: [ Everything! (Slower)  V ]
            [ Some stuff?             ]
            [ Nothing (Faster)        ]

...where full submodule support / full clean are the defaults.

I don't know if 3 levels is the right number of options for either of these. Maybe submodules only have "yes" or "no", or maybe running the commands costs so little in any reasonable setup that we just always do it. On the other hand, maybe there are 4 or more meaningful levels of cleaning available.

There could also be a "Complete Reclone" clean option which destroys the resource after a single use, or this could maybe be an option elsewhere ("[X] These resources are one-time use."). I suspect the tradeoffs by reusing resources are highly desirable for most reasonable workflows, but if you have a many-minutes-long build process anyway maybe shaving startup time from 2 minutes to 2 seconds doesn't really matter.

if you have a many-minutes-long build process anyway maybe shaving startup time from 2 minutes to 2 seconds doesn't really matter

that's the boat i'm in, we also do things like generate a .deb from the build output, so eliminating any possibility of cruft from previous working copies is important to us.

@epriestley : is making /var/drydock non hard written or just documented part of this ??