Arch Linux

archie_atlas

Member

Registered: 2021-05-08

Posts: 4

[SOLVED]Downgrade icu lightdm broken

Hi everyone,
I screwed up when upgrading icu (libicuuc.so.72) to version 73.2-1, similarly harfbuzz-icu 7.3.0-2 and now my lightdm fail to start so I access my laptop from tty (I'm posting from my phone).

Trying to debug I'm convinced it will all be solved by downgrading to libicuuc.so.72.

But I'm stuck in the following:

$ sudo pacman -U file:///var/cache/pacman/pkg/icu-72.1-2-x86_64.pkg.tar.zst
loading packages...
warning: downgrading package icu (73.2-1 => 72.1-2)
resolving dependencies...
looking for conflicting packages...
error: failed to prepare transaction (could not satisfy dependencies)
installing icu (72.1-2) breaks dependency 'libicuuc.so=73-64' required by harfbuzz-icu

When I try to downgrade harfbuzz-icu

$ sudo pacman -U file:///var/cache/pacman/pkg/harfbuzz-icu-7.1.0-1x86_64.pkg.tar.zst
loading packages...
warning: downgrading package harfbuzz-icu (7.3.0-2 => 7.1.0-1)
resolving dependencies...
warning: cannot resolve "libicuuc.so=72-64", a dependency of "hardbuzz-icu"
the following package cannot be upgraded due to unresolvable dependencies:
    harfbuzz-icu
Do you want to skip the above package for this upgrade [y/N]
error: failed to prepare transaction (could not satisfy dependencies)
Unable to satisfy dependency 'libicuuc.so=72-64' required by harfbuzz-icu

So I can't downgrade harfbuzz because I need a downgraded version of icu, for which I need a downgraded version of harfbuzz?

Both are dependencies of other packages so I'm not sure removing and reinstalling them is adequate. Should I run the above commands as chroot?

/var/log/lightdm/lightdm.log

Returns Required seat (seat0) has stopped and same as

sudo systemcl status lightdm.service

Returns failed, that display manger failed to start

Last edited by archie_atlas (2023-07-07 08:41:14)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,285

Re: [SOLVED]Downgrade icu lightdm broken

Partial upgrades are unsupported: https://wiki.archlinux.org/title/System … nsupported

You need to update your entire system not parts of it or you are going to have problems. In particular icu is a dependency of A LOT of stuff, all of which gets rebuilt when a new version of icu is released as necessary

If you really think you need to downgrade instead of upgrade pass all three packages to the same pacman -U invocation, which will hopefully make pacman recognize that that dep chain is safe.

Last edited by V1del (2023-07-07 02:45:47)

archie_atlas

Member

Registered: 2021-05-08

Posts: 4

Re: [SOLVED]Downgrade icu lightdm broken

thank you! issue was solved by calling both downgrades in same pacman -U invocation

Last edited by archie_atlas (2023-07-07 08:40:16)

Scimmia

Fellow

Registered: 2012-09-01

Posts: 13,729

Re: [SOLVED]Downgrade icu lightdm broken

No, worked around with that. The fix, as was already mentioned, is fully updating your system.