Yesterday with @infinisil on #nixos, he pointed me to: peti/jailbreak-cabal#7 after a good deal of time wrangling through a package to make it work.
The `nix-build -K` command, is very handy for debugging things like these, again I learnt from infinisil.
And after much experimenting and looking through, it turned out that jailbreaking wasn't working as expected, and its documentation could point it out to avoid future confusion.
webify needs a bump in the cabal file. As the last upstream commit is
two years ago, I think it makes sense to not wait for upstream to merge
the PR [0] and release a new version.
[0] https://github.com/ananthakumaran/webify/pull/27
This makes packages use lapack and blas, which can wrap different
BLAS/LAPACK implementations.
treewide: cleanup from blas/lapack changes
A few issues in the original treewide:
- can’t assume blas64 is a bool
- unused commented code
This closes#79441.
ghcWithPackages is using `ghc-pkg recache` to build its package
database. By doing so, it overrides the `package.cache[.lock]` files.
Details are unclear, but GHC 8.10 changed a bit the behavior.
Previously, it was unconditionally replacing the files by new ones. Now
it tries to open (for modification) the files. These files are symlinks
to another nix derivation, which is hence read-only.
This commit removes the files before running `ghc-pkg recache`, hence it
will just write the new files.
Tested with `haskellPackages.ghcWithPackages` (i.e. GHC 8.8) and
`haskell.packages.ghc8101.ghcWithPackages` (i.e GHC 8.10) with the
following nix file, at the root of the nixpkgs repository:
```
with import ./. {
overlays = [
(
self: super: {
haskellPackages = super.haskell.packages.ghc8101.override {
overrides = selfh: superh: {
th-lift-instances = super.haskell.lib.doJailbreak superh.th-lift-instances;
th-expand-syns = super.haskell.lib.doJailbreak superh.th-expand-syns;
th-reify-many = super.haskell.lib.doJailbreak superh.th-reify-many;
th-orphans = super.haskell.lib.doJailbreak superh.th-orphans;
haskell-src-meta = super.haskell.lib.doJailbreak superh.haskell-src-meta;
};
};
}
)
];
};
haskellPackages.ghcWithPackages(p:[p.PyF])
```
This will test with GHC 8.10. Comment out the `overlays` to test with
GHC 8.8.
