Arch Linux

Summary and Info:
-U only downloads the first package when using XferCommand.

Steps to Reproduce:
XferCommand = /usr/bin/wget --passive-ftp -c -O %o %u

$ sudo ./build/pacman -U --cachedir=/tmp/cache https://arch.hu.fo/archlinux/core/os/x86_64/pacman-5.2.2-3-x86_64.pkg.tar.zst https://arch.hu.fo/archlinux/core/os/x86_64/pacman-mirrorlist-20210405-1-any.pkg.tar.zst
:: Retrieving packages...
--2021-04-26 19:19:34-- https://arch.hu.fo/archlinux/core/os/x86_64/pacman-5.2.2-3-x86_64.pkg.tar.zst
Loaded CA certificate '/etc/ssl/certs/ca-certificates.crt'
Resolving arch.hu.fo (arch.hu.fo)... 185.190.82.139, 2403:5180:6:cafe::
Connecting to arch.hu.fo (arch.hu.fo)|185.190.82.139|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 858693 (839K) [application/zstd]
Saving to: ‘/tmp/cache/pacman-5.2.2-3-x86_64.pkg.tar.zst.part’

/tmp/cache/pacman-5.2.2-3-x86_64.pkg.tar.zst.part 100%[==========================================================================================================================================>] 838.57K --.-KB/s in 0.08s

2021-04-26 19:19:34 (10.4 MB/s) - ‘/tmp/cache/pacman-5.2.2-3-x86_64.pkg.tar.zst.part’ saved [858693/858693]

warning: download completed successfully but no file in the cache

$ ls /tmp/cache
pacman-5.2.2-3-x86_64.pkg.tar.zst