Harmless copy.c bug: Fail if no files match

[eduardocasino]

This was making copy.com to end silently when using wildcards if no files matched. Pretty harmless, but a bug is a bug 😉

[davidgiven]

Thanks --- merging. I actually think the copy logic for wildcards is pretty broken, but I'm not sure what the right behaviour should be so don't know how to fix it. What should 'copy foo.txt *.txt b:' do? Try to copy the same file twice? Error out? Deduplicate?

[eduardocasino]

For that particular case, I think that copy the same file twice and deduplicate are equally valid. The first is not efficient in terms of disk io, but it simplifies the logic. The later would be ideal, but then you have to transverse the stash for every new match. I would never error out.