Before, we'd always use `cc = null`, and check for that. The problem is
this breaks for cross compilation to platforms that don't support a C
compiler.
It's a very subtle issue. One might think there is no problem because we
have `stdenvNoCC`, and presumably one would only build derivations that
use that. The problem is that one still wants to use tools at build-time
that are themselves built with a C compiler, and those are gotten via
"splicing". The runtime version of those deps will explode, but the
build time / `buildPackages` versions of those deps will be fine, and
splicing attempts to work this by using `builtins.tryEval` to filter out
any broken "higher priority" packages (runtime is the default and
highest priority) so that both `foo` and `foo.nativeDrv` works.
However, `tryEval` only catches certain evaluation failures (e.g.
exceptions), and not arbitrary failures (such as `cc.attr` when `cc` is
null). This means `tryEval` fails to let us use our build time deps, and
everything comes apart.
The right solution is, as usually, to get rid of splicing. Or, baring
that, to make it so `foo` never works and one has to explicitly do
`foo.*`. But that is a much larger change, and certaily one unsuitable
to be backported to stable.
Given that, we instead make an exception-throwing `cc` attribute, and
create a `hasCC` attribute for those derivations which wish to
condtionally use a C compiler: instead of doing `stdenv.cc or null ==
null` or something similar, one does `stdenv.hasCC`. This allows quering
without "tripping" the exception, while also allowing `tryEval` to work.
No platform without a C compiler is yet wired up by default. That will
be done in a following commit.
luarocks defines by default the following mirrors:
83093e7da7/src/luarocks/core/cfg.lua (L205)
Let's add them to nixpkgs. I have modified luarocks-nix to generate the
proper nixpkgs urls.
I bump luarocks-nix in the following commits.
This is a new package that provides a shell hook to make it easy to
declare manpages and shell completions in a manner that doesn't require
remembering where to actually install them. Basic usage looks like
{ stdenv, installShellFiles, ... }:
stdenv.mkDerivation {
# ...
nativeBuildInputs = [ installShellFiles ];
postInstall = ''
installManPage doc/foobar.1
installShellCompletion --bash share/completions/foobar.bash
installShellCompletion --fish share/completions/foobar.fish
installShellCompletion --zsh share/completions/_foobar
'';
# ...
}
See source comments for more details on the functions.
applyPatches applies a list of patches to a source directory.
For example to patch nixpkgs you can use:
applyPatches {
src = pkgs.path;
patches = [
(pkgs.fetchpatch {
url = "1f770d2055.patch";
sha256 = "1nlzx171y3r3jbk0qhvnl711kmdk57jlq4na8f8bs8wz2pbffymr";
})
];
}
There ver very many conflicts, basically all due to
name -> pname+version. Fortunately, almost everything was auto-resolved
by kdiff3, and for now I just fixed up a couple evaluation problems,
as verified by the tarball job. There might be some fallback to these
conflicts, but I believe it should be minimal.
Hydra nixpkgs: ?compare=1538299
They always can be regenerated during the actual build, and they are sometimes
random, e.g in Tensorflow;
platforms -> NIX_BUILD_TOP/tmp/install/35282f5123611afa742331368e9ae529/_embedded_binaries/platforms
This setup hook modifies a Perl script so that any "-I" flags in its shebang
line are rewritten into a "use lib ..." statement on the next line. This gets
around a limitation in Darwin, which will not properly handle a script whose
shebang line exceeds 511 characters.
