Comment 8 for bug 1833229

@james-page I think the thing being overlooked is what it is doing, not wether or not the exception is correct. In our case, we have repositories that have some artifacts, and repositories that may have other artifacts... (and once in a rare while, overlap with different versions).. If we request a package that does *not* exist in the custom urls, then it will fail completely, instead of passing with the only failure being on that one repository. By default, it should check each of the repositories, see if they have it, etc.. It seems to be checking them all, but if *any* of them fails to have an artifact being requested, the entire pip operation implodes, even if the package *is* available in a different repository successfully prior to the fetching of the failed repo.