4 ms·

But which version should they provide? The dependency resolution still needs to happen somewhere ;)

by chriswarbo 3y ago

PhilipRoman 3y ago
The latest one obviously; any issues are left to the user as an exercise
- menaerus 3y ago
  That's quite surprising but I haven't delved into this topic basically never. Is it true that yum (dnf), apt and zypper took the approach by having SAT solvers under the hood? If so, why does arch take a different route?
  - rcxdude 3y ago
    Because it's easier for the developers. Arch's philosophy very much based on reducing the workload for maintainers. So they package things as close to vanilla as possible (and expect the users to make any adjustments, like enabling any services), package only one version, and have a rolling release which doesn't support older versions or even partial upgrades, so maintainers only really have to worry about making things work with the current version. They were one of the first distros to go exclusively systemd for the same reason of it allowed them to ditch their current init scripts and supporting both is a huge burden.
    - menaerus 3y ago
      Interesting. If I have a program A and if I run ldd on it, it outputs dep1, dep2, dep3 and dep4. Now I do the same on program B and ldd shows that it depends on dep1 and dep2, the same ones as from program A. If I want to update both of them, in the context of program A that would be partial update which AFAIU does not support? But in the context of program B that would be a "full" update. I'm not sure I understand what arch is going to do in this case?
      - rcxdude 3y ago
        "partial update" in this case means you update some packages without updating all of them (i.e. do 'pacman -Sy' followed by installing or upgrading any individual package). Usually what will happen is pacman will update those packages and any dependencies but not update any other packages will may now have been broken by that update . So if you were to pacman -Sy <program A> in this case then program B would probably be broken, and vice-versa (assuming any of the common deps have updated as well). If you were to update both then they might be fine but something else may break. https://wiki.archlinux.org/title/System_maintenance#Partial_upgrades_are_unsupported https://wiki.archlinux.org/title/System_maintenance#Partial_...
  - assbuttbuttass 3y ago
    I do not think yum or apt use a SAT solver. Instead, if they need multiple versions of a package, they just give them different names https://packages.debian.org/bookworm/guile-2.2 https://packages.debian.org/bookworm/guile-2.2 https://packages.debian.org/bookworm/guile-3.0 https://packages.debian.org/bookworm/guile-3.0
    - menaerus 3y ago
      From https://fedoraproject.org/wiki/Features/DNF#Including_libsolv_in_Fedora https://fedoraproject.org/wiki/Features/DNF#Including_libsol... > DNF is a fork of Yum 3.4 that uses libsolv via hawkey for a backend. The main goals of the project are: > using a SAT solver for dependency resolving allowing us to eventually use the same solver in rpm too > ...
- skummetmaelk 3y ago
  Interesting though that Arch users on the whole seem to experience less system problems than for example Ubuntu users.
  - rcxdude 3y ago
    a lot of that comes from the expectation that the user gets their hands dirty in actually configuring most packages in the first place. There's relatively little magic in arch. So both there's less stuff to break and when something does break the user usually can figure out the issue more easily (this is also helped by the selection pressure that is implied by the first expectation).

But which version should they provide? The dependency resolution still needs to happen somewhere ;)

PhilipRoman 3y ago

The latest one obviously; any issues are left to the user as an exercise

menaerus 3y ago
That's quite surprising but I haven't delved into this topic basically never. Is it true that yum (dnf), apt and zypper took the approach by having SAT solvers under the hood? If so, why does arch take a different route?
- rcxdude 3y ago
  Because it's easier for the developers. Arch's philosophy very much based on reducing the workload for maintainers. So they package things as close to vanilla as possible (and expect the users to make any adjustments, like enabling any services), package only one version, and have a rolling release which doesn't support older versions or even partial upgrades, so maintainers only really have to worry about making things work with the current version. They were one of the first distros to go exclusively systemd for the same reason of it allowed them to ditch their current init scripts and supporting both is a huge burden.
  - menaerus 3y ago
    Interesting. If I have a program A and if I run ldd on it, it outputs dep1, dep2, dep3 and dep4. Now I do the same on program B and ldd shows that it depends on dep1 and dep2, the same ones as from program A. If I want to update both of them, in the context of program A that would be partial update which AFAIU does not support? But in the context of program B that would be a "full" update. I'm not sure I understand what arch is going to do in this case?
    - rcxdude 3y ago
      "partial update" in this case means you update some packages without updating all of them (i.e. do 'pacman -Sy' followed by installing or upgrading any individual package). Usually what will happen is pacman will update those packages and any dependencies but not update any other packages will may now have been broken by that update . So if you were to pacman -Sy <program A> in this case then program B would probably be broken, and vice-versa (assuming any of the common deps have updated as well). If you were to update both then they might be fine but something else may break. https://wiki.archlinux.org/title/System_maintenance#Partial_upgrades_are_unsupported https://wiki.archlinux.org/title/System_maintenance#Partial_...
- assbuttbuttass 3y ago
  I do not think yum or apt use a SAT solver. Instead, if they need multiple versions of a package, they just give them different names https://packages.debian.org/bookworm/guile-2.2 https://packages.debian.org/bookworm/guile-2.2 https://packages.debian.org/bookworm/guile-3.0 https://packages.debian.org/bookworm/guile-3.0
  - menaerus 3y ago
    From https://fedoraproject.org/wiki/Features/DNF#Including_libsolv_in_Fedora https://fedoraproject.org/wiki/Features/DNF#Including_libsol... > DNF is a fork of Yum 3.4 that uses libsolv via hawkey for a backend. The main goals of the project are: > using a SAT solver for dependency resolving allowing us to eventually use the same solver in rpm too > ...
skummetmaelk 3y ago
Interesting though that Arch users on the whole seem to experience less system problems than for example Ubuntu users.
- rcxdude 3y ago
  a lot of that comes from the expectation that the user gets their hands dirty in actually configuring most packages in the first place. There's relatively little magic in arch. So both there's less stuff to break and when something does break the user usually can figure out the issue more easily (this is also helped by the selection pressure that is implied by the first expectation).