A separate function for building Bazel-bazed packages. Internally it splits the
build into two phases, fetching and building.
Users are expected to provide `fetchArgs.sha256` -- checksum of fetched
dependencies. Local dependencies should be removed in `fetchArgs.preInstall`.
Overall `fetchArgs` and `buildArgs` can be used to add specific steps to fetch
and build.
I originally wrote this for packaging proprietary games in Vuizvui[1]
but I thought it would be generally useful as we have a fair amount of
proprietary software lurking around in nixpkgs, which are a bit tedious
to maintain, especially when the library dependencies change after an
update.
So this setup hook searches for all ELF executables and libraries in the
resulting output paths after install phase and uses patchelf to set the
RPATH and interpreter according to what dependencies are available
inside the builder.
For example consider something like this:
stdenv.mkDerivation {
...
nativeBuildInputs = [ autoPatchelfHook ];
buildInputs = [ mesa zlib ];
...
}
Whenever for example an executable requires mesa or zlib, the RPATH will
automatically be set to the lib dir of the corresponding dependency.
If the library dependency is required at runtime, an attribute called
runtimeDependencies can be used to list dependencies that are added to
all executables that are discovered unconditionally.
Beside this, it also makes initial packaging of proprietary software
easier, because one no longer has to manually figure out the
dependencies in the first place.
[1]: https://github.com/openlab-aux/vuizvui
Signed-off-by: aszlig <aszlig@nix.build>
Closes: #34506
Among other things, this will allow *2nix tools to output plain data
while still being composable with the traditional
callPackage/.override interfaces.
Summary:
According to git-submodule manpage,
"git submodule status" prefixes the hash with a '-' if it is not
initialized, and other chars in other circumstances.
(this is consistent on the various git versions tested)
nix-prefetch-git runs "git submodule init" which does you'd think,
but apparently despite this earlier versions of git before 2.16
would still give the hash the '-' suffix.
In particular this is the behavior when using 2.15 and 2.14.1
from the nixos-17.09 and nixos-17.03 channels respectively.
The script then used awk to drop the first char of the first field
which does the wrong thing when there is no prefix emitted:
while there is a space character before the hash, this is not
part of the field and so we ended up eating the first character
of the hash.
To fix this in a way that also works with the previous behavior,
this commit instead uses awk to grab the hash field
and uses tr to delete any '-' chars should they be present.
This seems to work in my testing, and for example can now
successfully fetch the source for "nginxModules.brotli"
where previously it would generate an error:
fatal: '22564a95d9ab58865a096b8d9f7324ea5f2e03e' is not a commit and a branch 'fetchgit' cannot be created from it
(we dropped a '2' from the beginning of the hash)
We still ensure the old and new ones start, respectfully, with `a/` and
`b/`. Use with `stripLen` to ensure tha the old `a/` and `/b` are gone
if a new prefix is added.
