configuration-nix.nix uses builtins.intersectAttrs to not any overrides
for packages not present in `super` (presumably for use outside of
nixpkgs?). To accomodate it, we pass an attribute set with every
attribute of haskellPackages, but set to `null` as `super`, and — while
we're at it — a fix point as `self`.
While being able to test them is neat (on x86_64-linux they work very
well, actually), we usually don't want to do this, since the set is
only (recommended to be) used to bootstrap GHC. Consequently there is
almost no binary cache and testing them mostly leads to unenlightening
and seemingly endless compilation.
The added nix expression allows maintainers to check for regressions in
the configuration overlays employed by haskellPackages and friends. The
reasoning behind this is that, if we add an override for something, it
should also build. To test this fact, we extract all attributes touched
by a configuration and obtain all relevant derivations corresponding to
it which can then be thrown into nix-build --keep-going.
I've been using this expression to verify configuration-ghc-9.2.x.nix
for a week or so which works quite well. The amount of stale overrides
in other configuration makes it a bit more painful for other use cases
at the moment.
Allow setting the HACKAGE2NIX environment variable to change the
hackage2nix the script uses to an absolute path to a local build. Useful
to test local changes in a realistic environment.
We split configuration-hackage2nix.yaml into multiple files. We bump
cabal2nix-unstable to get support for multiple config files in
hackage2nix.
* The file main.yaml is only supposed to be edited by humans.
* The file stackage.yaml is only supposed to be updated by the
update-stackage.sh
* The file broken.yaml can be edited by humans, but probably future
helpers will want to insert broken packages into this file based on
hydra reports.
* The file transitive-broken.yaml is newly introduced to be generated
by regenerate-transitive-broken-packages.sh
regenerate-transitive-broken-packages.sh makes a nix query (in
transitive-broken-packages.nix) which evaluates all haskellPackages
once with and once without "allowBroken" this way it get's a list of
packages which are broken by some transitive dependency, but does not
disable packages which have eval errors not caused by a broken package.
This is the preferred format for things fetched from git or similar that
are not proper releases: https://nixos.org/manual/nixpkgs/stable/#sec-package-naming
Also we should think about making name and attribute name more
consistent: cabal2nix-latest -> cabal2nix-unstable
Introduces a script that can be used to update the Nix expressions for
the Haskell package set. In service of that, also
- introduces cabal2nix-latest, which pins the hackage2nix version used
- changes all-cabal-hashes to use fetchFromGitHub
- adds update-hackage.sh & update-cabal2nix-latest.sh & update-stackage.sh maintainer scripts
