We shouldn’t force the user to have a C compiler in scope, just
because the derivation is forced to build locally. That can’t be
counted as “lightweight” anymore.
Co-Authored-By: Silvan Mosberger<contact@infinisil.com>
A definition I’ve been copy-pasting everywhere so far, so it’s finally
time to add it to nixpkgs.
I’m using a remote builder for my regular nix builds, so trivial
`runCommand`s which first try a substitution and then copy the inputs
to the builder to run for 0.2s are quite noticable.
If we just always build these, we gain some build time, so let’s make
it easy to switch from remote to local.
tensorflow assumes $USER to be set to something, otherwise it complains
like this:
```
FATAL: $USER is not set, and unable to look up name of current user: (error: 0): Success
Traceback (most recent call last):
File "./configure.py", line 1602, in <module>
main()
File "./configure.py", line 1399, in main
_TF_MAX_BAZEL_VERSION)
File "./configure.py", line 478, in check_bazel_version
['bazel', '--batch', '--bazelrc=/dev/null', 'version'])
File "./configure.py", line 156, in run_shell
output = subprocess.check_output(cmd)
File "/nix/store/drr8qcgiccfc5by09r5zc30flgwh1mbx-python3-3.7.5/lib/python3.7/subprocess.py", line 411, in check_output
**kwargs).stdout
File "/nix/store/drr8qcgiccfc5by09r5zc30flgwh1mbx-python3-3.7.5/lib/python3.7/subprocess.py", line 512, in run
output=stdout, stderr=stderr)
```
Spotted while changing the hash of its fixed-output derivation on
purpose.
We could also set this in the tensorflow-specific part, but very likely,
other programs will fail as well.
This cuts down the dependency tree on some rust builds where a crate not
just exposes a binary but also a library. `$out/lib` contained a bunch
of extra support files that among other information carry linker flags
(including the full path to link-time dependencies). Worst case this led
to some binary outputs depending on the full build closure of rust
crates.
Moving all the `$out/lib` files to `$lib/lib` solves this nicely.
`lib` might be a bit weird here as they are most of the time just rlib
files (rust libraries). Those are essential only required during
compilation but they can also be shared objects (like with traditional
C-style packages). Which is why I went with `lib` for the new output.
One of the caveats we are running into here is that we do not (always)
know ahead of time of a crate produces just a library or just a binary.
Cargo allows for some ambiguity regarding whether or not a crate
provides one, two, … binaries and libraries as it's outputs. Ideally we
would be able to rely on the `crateType` entirely but so far that isn't
the case. More work on that area might show how difficult that actually
is.
Go beyond the obvious setup hooks now, with a bit of sed, with a skipped case:
- cc-wrapper's `dontlink`, because it already is handled.
Also, in nix files escaping was manually added.
EMP
Using wrapProgram adds a call to `bash` around every call
of `execline`, which clearly misses the basic idea behind
`execline` in the first place …
This reverts commit b64d25c447.
