GNOME 3.14 requires new fontconfig

[lucabrunox]

As per pango expression:

name = "pango-1.32.5"; #.6 and higher need fontconfig-2.11.* which is troublesome

However now newer gtk requires pango 1.36. Any ideas how can we work on upgrading fontconfig? @vcunat

[vcunat]

Oh, well, this is a nightmare. Just updating it should not be a problem, but systems with mixed versions behave very bad (including any non-nixos usage). The problem should be well-explained in #2050.

I have patches that were supposed to fix the problems, but they don't work and I couldn't find out why (so I laid it to rest ATM). The branch is topgit-style, pushed on https://github.com/vcunat/nixpkgs/tree/v/fonts.

[lucabrunox]

Sorry, asking here to not clutter #2050. Didn't understand much the problem. Does nix fontconfig currently use /etc? Why is a problem that /etc is "new" and fontconfig is "old" if we keep fontconfig up-to-date?

[vcunat]

@lethalman: /etc is set by nixos, but people will certainly keep some packages linked against older fontconfig versions, at least for some time. These will stop working at all (crash, IIRC). Similarly on non-nixos, you can very easily have incompatible /etc, as it is completely out of control.

[lucabrunox]

@vcunat about non-nixos wouldn't it be a problem already given /etc on non-nixos is probably against a more recent fontconfig?

[vcunat]

Yes, I think it may already be a problem on some distros that use 2.11 /etc/fonts*. I didn't investigate any details.

[lucabrunox]

So if I've understood correctly, it's about adding an /etc/fonts{fontconfig_major_breaker_version_here} as one of the fontconfig directories? I'm asking because I'd like to look at your branch, but know nothing about fontconfig.

[vcunat]

Yes, it's about config location. It should put the default config into ${fontconfig}/etc (each fontconfig its own version of default), and only read overrides from /etc/fonts-nix where the user is responsible to put stuff compatible with all versions (s)he uses.

[vcunat]

@lethalman: I'm planning to push several rebuild updates to staging, so it's better tested. (I'm running on those myself, only the commits need a little cleanup.) I did major updates of glib, cairo, and pango, but waited with gtk3 bump (and close dependencies) to sync them with gnome-3.14 switch. Is that right?

[vcunat]

OK, included the GTK+ 3.14 stack, after IRC discussion. In case someone wants to look at the commits before I clean&push them, vcunat/nixpkgs@NixOS:staging...vcunat:v/staging.

Closing in favor of #4410 which seems solved anyway, I think.