4 ms·

I think the definition should be: Installing any number of packages, then removing them in any order, at any future point(s) in time, is equivalent to never ha

by pkulak 3y ago

I think the definition should be: Installing any number of packages, then removing them in any order, at any future point(s) in time, is equivalent to never having installed them at all. This leaves some distros out, but I feel like it’s the important part of the concept.

infogulch 3y ago
I like that. Maybe you could say the package collection forms a lattice, where there is only one state for any subset of packages no matter how you got there.
colordrops 3y ago
This is called "reproduceability", meaning the same config always results in the same system state.
eru 3y ago
How deep do you want that property to apply? Have a look at 'uniquely represented datastructures' and 'History Independent Data Structures'. You'd need to take special care to make sure that your block device (eg SSD) allocates blocks independent of history.
nonameiguess 3y ago
As far as I can tell, her point is this is effectively impossible, at least for a user-facing system. Do you want all the files you wrote in your word processor program or text editor gone when you uninstall those? All the files you downloaded from your browser gone if you uninstall it? If not, there is no reliable way to tell what files are created by a program automatically and which are created by a human using that program. You can easily enough remove everything that was created during the installation process, but not all future changes. Beyond that, consider other changes, like say you decide to change DNS implementations and then later decide to change your default DNS server. If you uninstall the provider to change back to previous one, do you also want to change back to the old server you were using or do you want to retain that change? Personally, I'd want to only change the provider but keep the new server. Then consider difficulties with directories shared across multiple machines. Let's say you have /home/${USER} set up as an NFS or Samba mount so you can keep the same files across multiple workstations. If a program respects XDG config dirs and stores stuff in there and you uninstall on one workstation, should it remove the files from all of them? Do you want all your devices to be identical or do you only want the home directory to be identical? There is no possible way for a package manager on a single system to know this.
- pkulak 3y ago
  I'm saying that installing and removing packages is equivalent to not installing them at all, not that if your boyfriend leaves you, uninstalling LibreOffice should undo it.

by pkulak 3y ago

infogulch 3y ago

I like that. Maybe you could say the package collection forms a lattice, where there is only one state for any subset of packages no matter how you got there.

colordrops 3y ago

This is called "reproduceability", meaning the same config always results in the same system state.

eru 3y ago

How deep do you want that property to apply? Have a look at 'uniquely represented datastructures' and 'History Independent Data Structures'. You'd need to take special care to make sure that your block device (eg SSD) allocates blocks independent of history.

nonameiguess 3y ago

As far as I can tell, her point is this is effectively impossible, at least for a user-facing system. Do you want all the files you wrote in your word processor program or text editor gone when you uninstall those? All the files you downloaded from your browser gone if you uninstall it? If not, there is no reliable way to tell what files are created by a program automatically and which are created by a human using that program. You can easily enough remove everything that was created during the installation process, but not all future changes. Beyond that, consider other changes, like say you decide to change DNS implementations and then later decide to change your default DNS server. If you uninstall the provider to change back to previous one, do you also want to change back to the old server you were using or do you want to retain that change? Personally, I'd want to only change the provider but keep the new server. Then consider difficulties with directories shared across multiple machines. Let's say you have /home/${USER} set up as an NFS or Samba mount so you can keep the same files across multiple workstations. If a program respects XDG config dirs and stores stuff in there and you uninstall on one workstation, should it remove the files from all of them? Do you want all your devices to be identical or do you only want the home directory to be identical? There is no possible way for a package manager on a single system to know this.

pkulak 3y ago
I'm saying that installing and removing packages is equivalent to not installing them at all, not that if your boyfriend leaves you, uninstalling LibreOffice should undo it.