CLN rust dependency won't build on ppc64le

[grubles]

Rocky Linux 9's rustc and cargo versions:

$ rustc --version
rustc 1.58.1 (Red Hat 1.58.1-1.el9)

$ cargo --version
cargo 1.58.0

I've recently been hitting this error building CLN master:

genidx doc/index.rst
(cd plugins; cargo build --quiet --examples)
error: failed to parse manifest at `/home/user/builds/lightning/Cargo.toml`

Caused by:
  feature `strip` is required

  The package requires the Cargo feature called `strip`, but that feature is not stabilized in this version of Cargo (1.58.0).
  Consider trying a newer version of Cargo (this may require the nightly release).
  See https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#profile-strip-option for more information about the status of this feature.
make: *** [plugins/Makefile:210: target/debug/examples/cln-plugin-startup] Error 101

[vincenzopalazzo]

yeah, this is bad because we do not have the control over distribution version, what about installing rust from the official install script?
https://www.rust-lang.org/tools/install

[whitslack]

My Gentoo ebuild for Core Lightning deletes the strip = "debuginfo" line from Cargo.toml because stripping binaries for installation is the responsibility of the package manager, not of the build system, and stripping can be suppressed through Portage's nostrip feature flag, which doesn't work if the build system has already done it. Presumably if you delete that line as well, then your antique version of Cargo won't complain about it.

[grubles]

Commenting out the strip = "debuginfo" helps the build progress some, but then errors again. Looks like I'll have to reinstall rust using rustup in order to get a more recent version.

(cd plugins; cargo build --quiet --examples)
error: failed to run custom build command for `ring v0.16.20`

Caused by:
  process didn't exit successfully: `/home/user/builds/lightning/target/debug/build/ring-4dd82f7f52552798/build-script-build` (exit status: 101)
  --- stderr
  thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/ring-0.16.20/build.rs:358:10
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
error: build failed
make: *** [plugins/Makefile:210: target/debug/examples/cln-plugin-startup] Error 101
rm external/ppc64le-redhat-linux/libwally-core-build/src/secp256k1/libsecp256k1.la

[grubles]

Hrmmm even with a newer rustc, I get the same error:

error: failed to run custom build command for `ring v0.16.20`

Caused by:
  process didn't exit successfully: `/home/user/builds/lightning/target/debug/build/ring-7f3889cbf68c3d25/build-script-build` (exit status: 101)
  --- stderr
  thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/ring-0.16.20/build.rs:358:10
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
make: *** [plugins/Makefile:210: target/debug/examples/cln-plugin-startup] Error 101
rm external/ppc64le-redhat-linux/libwally-core-build/src/secp256k1/libsecp256k1.la

$ rustc --version
rustc 1.65.0 (897e37553 2022-11-02)

[cdecker]

We could use HAVE_CARGO configure value reflect whether we have a rustc that is recent enough.

[vincenzopalazzo]

I think it is not a version problem but ring does not support some platform briansmith/ring#562 and the error is a little bit cryptic because it is caused by this unwrap.

I think the only solution is disabling rust?

[grubles]

I was starting to suspect that was the case since I'm running on powerpc64le rather than ARM or x86. :-/

[cdecker]

Ok, then we might get away by setting RUST=0 in config.vars, that'll tell make to skip Rust components. Sadly that means that the cln-grpc will also not be compiled.

[grubles]

The --disable-rust configure flag seems to work for this.

[whitslack]

The --disable-rust configure flag seems to work for this.

That's how we disable building+installing the Rust components on Gentoo when the user configures USE="-rust" despite having Rust installed. Works perfectly.

[cdecker]

Yeah, sorry about that, hopefully ring adds support to ppc, alternatively we could fall back on openssl rather than rustls (which then pulls in ring as a transitive dependency). Though not quite sure how to realize that type of config changes from the ./configure script to the Cargo.toml in plugins/grpc-plugin, but we'll find a way.