We are replicating one mechanism behind `-Z build-std`.
There isn't yet crate2nix support for this, but one can (and I do) add
the missing stdlib deps (for this feature to pick up) with overrides.
With Rust 1.61, it is necessary to link to external static/dynamic libaries
when building the rlib that uses them, rather than when linking the final
binary. In fact, it is no longer necessary to specify the libraries to link
when building the final binary, but the library search path flags must still
be included.
This parameter is being set to `$NIX_BUILD_CORES` by default. This is a
standard practice but there's a suspicion that this can produce broken
builds. For some details see
https://github.com/cargo2nix/cargo2nix/issues/184 . As a
work-around/test, it'd be good if codegen-units can be set to something
constant, such as `1`. This PR allows it.
Note that the default of `$NIX_BUILD_CORES` is preserved so this MR
causes no change in default behaviour and no rebuilds.
These features are internal-only, have special characters that bash
doesn't support in variable names, and aren't normally given
environment variables by cargo as far as I can tell.
According to rustc implementation[1], `-C incremental=no` enables
incremental builds with directory name `no`. This patch removes the
`-C incremental` argument to disable incremental builds.
[1]: ee86f96ba1/compiler/rustc_session/src/options.rs (L918-L919)
As @lopsided98 points out in #105305, since the hashes are now target
sensative, and until we find reason to actually care to test what they
are exactly, we are best just normalizing them away in the tests.
Bofore this change, NUM_JOBS was set to 1. Some crates for building
C/C++ code (e.g. the cc and cmake crates), rely on this variable to
set the number of jobs. As a consequence, we were compiling embedded
libraries serially. Change this to NIX_BUILD_CORES to permit parallel
builds.
Prior discussion:
https://github.com/NixOS/nixpkgs/pull/50452#issuecomment-439407547
Cargo sets `CARGO_FEATURE_*` for all features when running a build
script:
https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-build-scripts
Some crates have build scripts (e.g. openblas-src) that rely on the
feature variables being properly set.
Since we now need several representations of features, this change
also updates `createFeatures` to be a list of features, rather than
`rustc` feature arguments. `configureCrate` and `buildCrate` then
build the required representations as-needed.
Fixes#68978
I know, heretic, but...
I also know that this is not perfect but it is a good start, I think. It
would be nice if this were part of the automatic "nixdoc" function
reference. I'd like guidance if this should be part of the rust section
or something else.
As it turns out Darwin does most of the things differently then "normal"
systems. They are using a different shared library extension and require
an obscure commandline parameter that has to be added to every build
system out there. That issue seems to be with clang on Darwin as on
Linux that flag isn't required to build the very same tests (when using
clang).
After adjusting these two details the tests are running fine on the
darwin box that I was able to obtain.
According to the Cargo documentation:
> The build script does not have access to the dependencies listed in
> the dependencies or dev-dependencies section (they’re not built
> yet!). Also, build dependencies are not available to the package
> itself unless also explicitly added in the [dependencies] table.
https://doc.rust-lang.org/cargo/reference/build-scripts.html
This change separates linkage of regular dependencies and build
dependencies.
* Make errors include the crate name and make them much more prominent.
* Move more code into lib.sh
* Already source generated logging code and lib.sh in configure
By overriding each dependency on every level of the dependency tree we
are creating a lot of unnecessary instances of the same derivation
Looking at the output size of `nix-instantiate --trace-function-calls
-vvvv …` and the execution time I got about a 10x improvement after
applying this change.
It was probably good intentions that lead to these overrides but in
practice no tooling (that I know of) really needs this. `carnix` and
`crate2nix` are fine without those overrides. Furthermore I believe that
it is the job of the tooling around `buildRustCrate` to provide a
coherent set of overrides. By not enforcing all of the overrides, debug
flags, verbosity, … to be the same throughout the closure we also allow
consumers to override specific aspects of the crates. Some (older?)
crates might need different `crateOverrides` then newer crates with the
same name. Currently such situations can not (easily) be implemented
with the override in-place.
Previously I did use `runCommand` to do the same. Using
releaseTools.aggregate seems a lot saner and we might get nicer hydra
output of the tests that are failing.
It used to be the case (ref missing) that cargo did treat
`src/$libName.rs` as an alternative to `src/lib.rs` when the latter
wasn't present. Recently I failed to reproduce that with vanilla cargo
and it started to cause pain with some crates of the form:
some_crate/
`- src
`- main.rs
`- some_crate.rs
We would build `src/some_crate.rs` and thing it is a library while that
might not be the actual case. This crate is a valid `bin` crate not a
`lib` crate as far as I can tell from the samples I took.
I removed support for the previously required heuristic and commented
out the test cases in case we will need them again. We could crawl in
the Git history but chances are that the next person looking into this
doesn't know about the history.
