"usd clone" is not fatal when lpusip is empty

23:53 <nacc> rbasak: for `usd clone`'s usage of fetch_remote, shouldn't lpusip not existing be fatal?

23:53 <nacc> rbasak: lpmep not existing is whatever, but i'm not sure we have a reasonable usecase for
             using usd without having an imported tree?

01:23 <rbasak> nacc: agreed. Did I screw that up when refactoring?

15:05 <nacc> rbasak: looks like it is explicitly set to ignore_nonexistent=True in both cases
             (lpusip/lpmep)

15:06 <nacc> rbasak: i wonder if we can also rather than simply raise the CalledProcessError in the case
             of ignore_nonexistent=False, logging.exception('a useful message') and sys.exit(1)?

15:45 <nacc> rbasak: yeah taht would be fine with me -- just thinking that the exception backtrace is
             not going to be that useful to end-users or us, as it's a potentially clear issue (probably
             a mis-typed srcpkg)

15:46 <rbasak> nacc: we can catch CLIError at the top level, print the string and exit the exit code
               only.

15:46 <rbasak> I don't know what others think of that method. I've used it in the past as it feels the
               cleanest (eg. with testing).

15:47 <rbasak> assertRaises(CliError...) instead of having to mock out sys.exit, etc.

15:47 <nacc> rbasak: i think i'd be happy with that

15:47 <nacc> rbasak: if you don't have time for it right now, i'd also be happy with
             ignore_nonexistent=True for lpusip and a bug filed for refactoring :)