The installation media should not even be offered as a choice to install Arch Linux to

[dylanmtaylor]

I saw someone hit this last night (Eastern time) in the help channel on Discord.

Scenario:

• Arch ISO burned to USB drive mounted on /dev/sda
• /dev/sda chosen as target, and user chose to format /dev/sda and install there thinking it was their hard drive (their real drive was an NVMe SSD, on nvme0n1 - they didn't notice the sizes)
• parted mklabel command failed due to mounted partitions
• Manual unmount of /dev/sda partitions failed due to it being the Arch ISO

I propose that, if we can somehow detect the installer is running off of a block device, not listing that device as an option in guided.

[Torxed]

We should be able to map /dev/loop0 (when ISO is used) or /dev/sda (if USB is used) against the logical device and filter the real device out. I believe archinstall.Partition('/run/archiso/airrootfs').real_device will turn out to be /dev/sda in this case, in which case we can filter out /dev/sda as it maps against the airrootfs device.

Pesudo code but .real_device exists in the library and could potentially be utilized.