Hi,
> It's fine, but it would be better for both function's argument to follow 
> projectile-add-known-project (meaning, call it 'project-root').

See attached patch.

>
> Regarding report-message, I figured it would just be a separate 
> 'message' call in both caller functions. Apparently that might to this 
> message appearing more often (due to the requested project not actually 
> appearing in project--list?), but I wonder if we shouldn't replace that 
> when-let with a presence assertion instead.

Yeah, we could do that. However, the nice thing now is at least that the
behavior is bundled together, so we don't need to remember to
report. Not sure what is best :)

>
> Anyway, the latter is not a big deal; project--remove-from-project-list 
> can be changed at any time later.

Sure! Do the manual later, or now?

--
Theo