fontconfig_210: remove package

[flokli]

This removes the fontconfig_210 package, as well as the only remaining usage, the rendering of 2.10.x config and cache.

I switched my system to this, and didn't spot any breakages.

Motivation for this change

Closes #88289

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[flokli]

There's a lot more of (now possibly unused) code - there's make-fonts-conf.xsl used to post-massage fontconfigs /etc/fonts/font.conf file to include fontDirectories - and to load files from the versioned subdir.

This is also exposed as makeFontsConf (which seems to be used in various places)

For now I decide to keep this, to not change too much at once, but I assume we might want to remove the configVersion parts in there, too.

[jtojnar]

This looks great but I would like to hold off on merging this until we have dealt with the possible fallback from #73795

[jtojnar]

There's a lot more of (now possibly unused) code - there's make-fonts-conf.xsl used to post-massage fontconfigs /etc/fonts/font.conf file to include fontDirectories - and to load files from the versioned subdir.

This is also exposed as makeFontsConf (which seems to be used in various places)

For now I decide to keep this, to not change too much at once, but I assume we might want to remove the configVersion parts in there, too.

Yeah, the XSL stylesheet does two things at once. The reason why it is used in the fontconfig derivation is precisely to introduce the versioned include so we cannot remove the fontconfigConfigVersion variable or fontconfig would no longer load its global configuration.

[flokli]

@jtojnar has there been any breakage reported already, or do you mean you just want to await one staging cycle?

[flokli]

Yeah, the XSL stylesheet does two things at once. The reason why it is used in the fontconfig derivation is precisely to introduce the versioned include so we cannot remove the fontconfigConfigVersion variable or fontconfig would no longer load its global configuration.

I'd propose removing the fontconfigConfigVersion parts from the xslt stylesheet, if the support fontconfig was the only (remaining?) consumer of it. (But in a followup PR after this one)

[jtojnar]

@jtojnar has there been any breakage reported already, or do you mean you just want to await one staging cycle?

Yeah, I would like to wait one staging cycle, or maybe slightly more since the channels lag a bit behind.

I'd propose removing the fontconfigConfigVersion parts from the xslt stylesheet, if the support fontconfig was the only (remaining?) consumer of it. (But in a followup PR after this one)

The current fontconfig needs it too, since it is the mechanism that makes it load the global config.

[flokli]

We had enough some staging rounds since #93562 (review).

Rebased to latest master.

[flokli]

Edit: moved over into #95319.

[NickHu]

NixOS module fonts.fontconfig.penultimate still relies on fontconfig_210 and will trip the assertion. I suppose that the code which generates the fontconfig 2.10 caches in that module can be deleted.

[jtojnar]

This is another section that should remain removed from edf2541. See #86601 (comment)

[flokli]

Not sure I grok this. Can you file a PR to master on what's needed to change?

[jtojnar]

These six lines should have remained removed. I will not get to filing PR before tomorrow.