Morgan Adamiec authored Jul 11, 2021 and Allan McRae committed Sep 04, 2021

archweb's download links all ended in /download. This cause all the temp
files to be named download.part. With parallel downloads this results in
multiple downloads to go to the same temp file and breaks the transaction.

Assign random temporary filenames to downloads from URLs that are either
missing a filename, or if the filename does not contain at least three
hyphens (as a well formed package filename does).

While this approach to determining when to use a temporary filename is
not 100% foolproof, it does keep nice looking download progress bar names
when a proper package filename is given. The only downside of not using
temporary files when provided with a filename  with three or more hyphens
is URLs created specifically to bypass temporary filename usage can not
be downloaded in parallel. We probably do not want to download packages
from such URLs anyway.

Fixes FS#71464

Modified-by: Allan McRae (do not use temporary files for realish URLs)
Signed-off-by: Allan McRae <allan@archlinux.org>