As requested in #99553. Closes#99553.
Libraries that install python modules as part of the build are
problematic, because they either
- only support a single python version, because the input for
pythonPackages gets fixed in all-packages.nix, or
- need to be rebuild the underlying C code for *every* python version
resulting in libfoo-python37, libfoo-python38, and so on
We would prefer to use the second approach because it works correctly
for all versions of python. However, it creates duplicate copies of
libseccomp.so and that can be expensive. Instead we 'deduplicate' the
copies of libseccomp.so by
- attaching a new $pythonsrc output to the libseccomp deriv, and
- exposing a new 'seccomp' package in python-packages.nix using
libseccomp as input, and
- having a custom python.nix derivation that builds the cython
extension using libseccomp to get the python source and the
package version
This means we build 1 copy of the seccomp python package, one for each
version of python, but all of those packages refer to a single instance
of the libseccomp C library, giving us the best of both worlds.
NOTE: because this requires changing the postInstall of libseccomp, it
requires a mass rebuild.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
TLDR: default.nix was pointing to an unmaintained code base whereas stable.nix is up-to-date and maintained.
History
1. At first their was one Python version of vdirsyncer that had been working fine for years. Then, maintenance decreased and the package was marked as broken in nixpkgs.
2. The original author (@untitaker on github.com) of vdirsyncer decided to re-implement (part of) vdirsyncer in Rust. Nixpkgs made `vdirsyncer` point to the Rust version and renamed the Python historical version to `vdirsyncerStable`.
3. Eventually, @untitaker gave up on the Rust version.
4. Someone else (@WhyNotHugo on github.com) decided to take over maintenance of the Python version.
5. Mario Rodas (@marsam on github) and Damien Cassou updated the `vdirsyncerStable` to point to the work of @WhyNotHugo and mark the package as working again.
Sandro