If the nix store lives on NFS, `ghc 8.2.1` is unable to build a package
database. This bug was fixed by @bgamari in `ghc 8.2.2` here:
https://ghc.haskell.org/trac/ghc/ticket/13945
This commit upgrades the unpacked bootstrap GHC version, so that we can build
newer versions of GHC even if the store is on NFS.
We keep the latest minor release of each one of the last 3 major releases,
which currently are GHC versions 8.2.2, 8.4.4, and 8.6.1. We also have
ghc-HEAD, but this doesn't count.
Dropping these compilers implied that we have to drop the corresponding
versions of ghcjs, too. We can also drop a shitload of obsolete compiler
patches that newer versions no longer need.
At some point, we can probably simplify the generic builder, too.
The per-version `default.nix`es just fill in default arguments. It is
much more useful to have the `.override` from the inner `callPackage`,
for finer control. Converting the outer `callPackage` to a plain import
makes the inner one the only one, revealing its `.override`.
The compilers themselves can pull them from `bootPkgs`, where they
should always come from anyways. This enforces that, simplifies that
code, and allows use to avoid more `rec { ... }` too.
Fixes mass build failures in these package sets,
due to "unknown pacakge: integer-simple".
Attributes that demonstrate this (see before/after):
* haskell.packages.integer-simple.ghc843.hello
* haskell.packages.integer-simple.ghc802.scientific
The second one is from the NixOS manual, FWIW.
Setting haskell.packageOverrides like so:
haskell = super.haskell // {
packageOverrides = self: super: {
my-package = ...;
my-other-package = ...;
};
};
causes all compiler-specific package sets to be overridden with those
overrides.
None of these old compilers are used anywhere in Nixpkgs, and keeping those
builds working in the face of regular updates of GCC, binutils, and whatnot is
too much effort for no obvious benefit.
- ghc versions 6.10.4, 6.12.3, and 7.2.2 are broken, and 6.10.2-binary is no
longer necessary after those versions have been dropped
- halvm version 2.4.0 hasn't compiled in a long time
- uhc version 1.1.9.4 hasn't compiled in a long time
We support only the last three major releases, i.e. 7.10.x is the latest
compiler we worry about.
The *compiler* is still there, though; it's just the package set that's been
removed.
This change brings development feedback loop improvement
from a couple of ghc rebuilds to only one for working on generic
builder.
To completely eliminate the rebuilds, use two nixpkgs clones
and point boot packages to the unmodified one.
