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.
* ghcHEAD: bump to 8.11.20200403
* ghcHead: reduce diff vs. 8.10.1
dontAddExtraLibs was removed by accident (IMO) in ea19a8ed1e
* ghcHEAD: add ability to use system libffi
- enable nixpkgs' libffi
- minimise diffs against 8.10.1
- remove patching
* remove configure warning about --with-curses-includes
configure: WARNING: unrecognized options: --with-curses-includes
* nixos/k3s: simplify config expression
* nixos/k3s: add config assertions and trim unneeded bits
* nixos/k3s: add a test that k3s works; minor module improvements
This is a single-node test. Eventually we should also have a multi-node
test to verify the agent bit works, but that one's more involved.
* nixos/k3s: add option description
* nixos/k3s: add defaults for token/serveraddr
Now that the assertion enforces their presence, we dont' need to use the typesystem for it.
* nixos/k3s: remove unneeded sudo in test
* nixos/k3s: add to test list
The patch phase runs after the build phase. Which means than when
using an override to override both 'conf' and 'patches' to provide
a custom config file and apply some patches, it doesn't work:
- first the patches applied (optionally changing config.def.h)
- then preBuild is run which overrides config.def.h with the user
supplied one (effectively cancelling previously applied patches)
By copying the config file in the prePatch phase instead, changes
are kept and applied in order.
