depot/doc/packages/xorg.section.md

X.org

The Nix expressions for the X.org packages reside in pkgs/servers/x11/xorg/default.nix. This file is automatically generated from lists of tarballs in an X.org release. As such it should not be modified directly; rather, you should modify the lists, the generator script or the file pkgs/servers/x11/xorg/overrides.nix, in which you can override or add to the derivations produced by the generator.

Katamari Tarballs

X.org upstream releases used to include katamari releases, which included a holistic recommended version for each tarball, up until 7.7. To create a list of tarballs in a katamari release:

export release="X11R7.7"
export url="mirror://xorg/$release/src/everything/"
cat $(PRINT_PATH=1 nix-prefetch-url $url | tail -n 1) \
  | perl -e 'while (<>) { if (/(href|HREF)="([^"]*.bz2)"/) { print "$ENV{'url'}$2\n"; }; }' \
  | sort > "tarballs-$release.list"

Individual Tarballs

The upstream release process for X11R7.8 does not include a planned katamari. Instead, each component of X.org is released as its own tarball. We maintain pkgs/servers/x11/xorg/tarballs.list as a list of tarballs for each individual package. This list includes X.org core libraries and protocol descriptions, extra newer X11 interface libraries, like xorg.libxcb, and classic utilities which are largely unused but still available if needed, like xorg.imake.

Generating Nix Expressions

The generator is invoked as follows:

cd pkgs/servers/x11/xorg
<tarballs.list perl ./generate-expr-from-tarballs.pl

For each of the tarballs in the .list files, the script downloads it, unpacks it, and searches its configure.ac and *.pc.in files for dependencies. This information is used to generate default.nix. The generator caches downloaded tarballs between runs. Pay close attention to the NOT FOUND: $NAME messages at the end of the run, since they may indicate missing dependencies. (Some might be optional dependencies, however.)

Overriding the Generator

If the expression for a package requires derivation attributes that the generator cannot figure out automatically (say, patches or a postInstall hook), you should modify pkgs/servers/x11/xorg/overrides.nix.