Question regarding rustc override

[ritchie46]

Hi, I am using maturin to build a library. Now there has been a change in the nightly compiler.

rust-lang/packed_simd#321

The CI of other projects can fix this by setting a nightly version from before 2021-03-24. However, if with maturin==0.9.4 this doesn't help and it keeps failing on the feature gate introduced in a recent feature of nightly.

This is the failing pipeline. Could this be related to anything maturin does? Could I see which rustc version maturin gets?

[messense]

Can you try cd py-polars && rustup override set nightly-2021-03-05 && ./tasks.sh test && cd .. ?

maturin does nothing special regarding Rust toolchain channel when building cdylib:

maturin/src/compile.rs

Lines 103 to 227 in 5b7efcc

	fn compile_target(
	context: &BuildContext,
	python_interpreter: Option<&PythonInterpreter>,
	bindings_crate: &BridgeModel,
	) -> Result<HashMap<String, PathBuf>> {
	let mut shared_args = vec!["--manifest-path", context.manifest_path.to_str().unwrap()];
	shared_args.extend(context.cargo_extra_args.iter().map(String::as_str));
	if context.release {
	shared_args.push("--release");
	}
	let mut rustc_args: Vec<&str> = context
	.rustc_extra_args
	.iter()
	.map(String::as_str)
	.collect();
	let mut rust_flags = env::var_os("RUSTFLAGS").unwrap_or_default();
	// We need to pass --bins / --lib to set the rustc extra args later
	// TODO: What do we do when there are multiple bin targets?
	match bindings_crate {
	BridgeModel::Bin => shared_args.push("--bins"),
	BridgeModel::Cffi | BridgeModel::Bindings(_) | BridgeModel::BindingsAbi3(_, _) => {
	shared_args.push("--lib");
	// https://github.com/rust-lang/rust/issues/59302#issue-422994250
	// We must only do this for libraries as it breaks binaries
	// For some reason this value is ignored when passed as rustc argument
	if context.target.is_musl_target() {
	rust_flags.push(" -C target-feature=-crt-static");
	}
	}
	}
	let module_name = &context.module_name;
	let so_filename = match python_interpreter {
	Some(python_interpreter) => python_interpreter.get_library_name(module_name),
	// abi3
	None => {
	format!("{base}.abi3.so", base = module_name)
	}
	};
	// Change LC_ID_DYLIB to the finaly .so name for macOS targets to avoid linking with
	// non-existent library.
	// See https://github.com/PyO3/setuptools-rust/issues/106 for detail
	let macos_dylib_install_name = format!("link-args=-Wl,-install_name,@rpath/{}", so_filename);
	// https://github.com/PyO3/pyo3/issues/88#issuecomment-337744403
	if context.target.is_macos() {
	if let BridgeModel::Bindings(_) | BridgeModel::BindingsAbi3(_, _) = bindings_crate {
	let mac_args = &[
	"-C",
	"link-arg=-undefined",
	"-C",
	"link-arg=dynamic_lookup",
	"-C",
	&macos_dylib_install_name,
	];
	rustc_args.extend(mac_args);
	}
	}
	if context.strip {
	rustc_args.extend(&["-C", "link-arg=-s"]);
	}
	let pythonxy_lib_folder;
	if let BridgeModel::BindingsAbi3(_, _) = bindings_crate {
	// NB: We set PYO3_NO_PYTHON further below.
	// On linux, we can build a shared library without the python
	// providing these symbols being present, on mac we can do it with
	// the `-undefined dynamic_lookup` we use above anyway. On windows
	// however, we get an exit code 0xc0000005 if we try the same with
	// `/FORCE:UNDEFINED`, so we still look up the python interpreter
	// and pass the location of the lib with the definitions.
	if context.target.is_windows() {
	let python_interpreter = python_interpreter
	.expect("Must have a python interpreter for building abi3 on windows");
	pythonxy_lib_folder = format!("native={}", python_interpreter.libs_dir.display());
	rustc_args.extend(&["-L", &pythonxy_lib_folder]);
	}
	}
	let cargo_args = vec!["rustc", "--message-format", "json"];
	let build_args: Vec<_> = cargo_args
	.iter()
	.chain(&shared_args)
	.chain(&["--"])
	.chain(&rustc_args)
	.collect();
	let command_str = build_args
	.iter()
	.fold("cargo".to_string(), |acc, x| acc + " " + x);
	let mut let_binding = Command::new("cargo");
	let build_command = let_binding
	.env("RUSTFLAGS", rust_flags)
	.args(&build_args)
	// We need to capture the json messages
	.stdout(Stdio::piped())
	// We can't get colored human and json messages from rustc as they are mutually exclusive,
	// but forwarding stderr is still useful in case there some non-json error
	.stderr(Stdio::inherit());
	if let BridgeModel::BindingsAbi3(_, _) = bindings_crate {
	// This will make pyo3's build script only set some predefined linker
	// arguments without trying to read any python configuration
	build_command.env("PYO3_NO_PYTHON", "1");
	}
	if let Some(python_interpreter) = python_interpreter {
	// `python_interpreter.executable` could be empty when cross compiling
	if python_interpreter.executable != PathBuf::new() {
	if bindings_crate.is_bindings("pyo3") {
	build_command.env("PYO3_PYTHON", &python_interpreter.executable);
	}
	// rust-cpython, and legacy pyo3 versions
	build_command.env("PYTHON_SYS_EXECUTABLE", &python_interpreter.executable);
	}
	}
	let mut cargo_build = build_command.spawn().context("Failed to run cargo")?;

[ritchie46]

That did the trick, I assumed that all subdirectories also were included. Thank you.