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|
use std::env;
use std::ffi::OsString;
use std::path::Path;
use std::process::{self, Command, Stdio};
use std::str;
#[cfg(all(feature = "backtrace", not(feature = "std")))]
compile_error! {
"`backtrace` feature without `std` feature is not supported"
}
fn main() {
let mut error_generic_member_access = false;
if cfg!(feature = "std") {
println!("cargo:rerun-if-changed=build/probe.rs");
let consider_rustc_bootstrap;
if compile_probe(false) {
// This is a nightly or dev compiler, so it supports unstable
// features regardless of RUSTC_BOOTSTRAP. No need to rerun build
// script if RUSTC_BOOTSTRAP is changed.
error_generic_member_access = true;
consider_rustc_bootstrap = false;
} else if let Some(rustc_bootstrap) = env::var_os("RUSTC_BOOTSTRAP") {
if compile_probe(true) {
// This is a stable or beta compiler for which the user has set
// RUSTC_BOOTSTRAP to turn on unstable features. Rerun build
// script if they change it.
error_generic_member_access = true;
consider_rustc_bootstrap = true;
} else if rustc_bootstrap == "1" {
// This compiler does not support the generic member access API
// in the form that anyhow expects. No need to pay attention to
// RUSTC_BOOTSTRAP.
error_generic_member_access = false;
consider_rustc_bootstrap = false;
} else {
// This is a stable or beta compiler for which RUSTC_BOOTSTRAP
// is set to restrict the use of unstable features by this
// crate.
error_generic_member_access = false;
consider_rustc_bootstrap = true;
}
} else {
// Without RUSTC_BOOTSTRAP, this compiler does not support the
// generic member access API in the form that anyhow expects, but
// try again if the user turns on unstable features.
error_generic_member_access = false;
consider_rustc_bootstrap = true;
}
if error_generic_member_access {
println!("cargo:rustc-cfg=std_backtrace");
println!("cargo:rustc-cfg=error_generic_member_access");
}
if consider_rustc_bootstrap {
println!("cargo:rerun-if-env-changed=RUSTC_BOOTSTRAP");
}
}
let rustc = match rustc_minor_version() {
Some(rustc) => rustc,
None => return,
};
if rustc < 51 {
// core::ptr::addr_of
// https://blog.rust-lang.org/2021/03/25/Rust-1.51.0.html#stabilized-apis
println!("cargo:rustc-cfg=anyhow_no_ptr_addr_of");
}
if rustc < 52 {
// core::fmt::Arguments::as_str
// https://blog.rust-lang.org/2021/05/06/Rust-1.52.0.html#stabilized-apis
println!("cargo:rustc-cfg=anyhow_no_fmt_arguments_as_str");
// #![deny(unsafe_op_in_unsafe_fn)]
// https://github.com/rust-lang/rust/issues/71668
println!("cargo:rustc-cfg=anyhow_no_unsafe_op_in_unsafe_fn_lint");
}
if !error_generic_member_access && cfg!(feature = "std") && rustc >= 65 {
// std::backtrace::Backtrace
// https://blog.rust-lang.org/2022/11/03/Rust-1.65.0.html#stabilized-apis
println!("cargo:rustc-cfg=std_backtrace");
}
}
fn compile_probe(rustc_bootstrap: bool) -> bool {
if env::var_os("RUSTC_STAGE").is_some() {
// We are running inside rustc bootstrap. This is a highly non-standard
// environment with issues such as:
//
// https://github.com/rust-lang/cargo/issues/11138
// https://github.com/rust-lang/rust/issues/114839
//
// Let's just not use nightly features here.
return false;
}
let rustc = cargo_env_var("RUSTC");
let out_dir = cargo_env_var("OUT_DIR");
let probefile = Path::new("build").join("probe.rs");
// Make sure to pick up Cargo rustc configuration.
let mut cmd = if let Some(wrapper) = env::var_os("RUSTC_WRAPPER") {
let mut cmd = Command::new(wrapper);
// The wrapper's first argument is supposed to be the path to rustc.
cmd.arg(rustc);
cmd
} else {
Command::new(rustc)
};
if !rustc_bootstrap {
cmd.env_remove("RUSTC_BOOTSTRAP");
}
cmd.stderr(Stdio::null())
.arg("--edition=2018")
.arg("--crate-name=anyhow")
.arg("--crate-type=lib")
.arg("--emit=dep-info,metadata")
.arg("--out-dir")
.arg(out_dir)
.arg(probefile);
if let Some(target) = env::var_os("TARGET") {
cmd.arg("--target").arg(target);
}
// If Cargo wants to set RUSTFLAGS, use that.
if let Ok(rustflags) = env::var("CARGO_ENCODED_RUSTFLAGS") {
if !rustflags.is_empty() {
for arg in rustflags.split('\x1f') {
cmd.arg(arg);
}
}
}
match cmd.status() {
Ok(status) => status.success(),
Err(_) => false,
}
}
fn rustc_minor_version() -> Option<u32> {
let rustc = cargo_env_var("RUSTC");
let output = Command::new(rustc).arg("--version").output().ok()?;
let version = str::from_utf8(&output.stdout).ok()?;
let mut pieces = version.split('.');
if pieces.next() != Some("rustc 1") {
return None;
}
pieces.next()?.parse().ok()
}
fn cargo_env_var(key: &str) -> OsString {
env::var_os(key).unwrap_or_else(|| {
eprintln!(
"Environment variable ${} is not set during execution of build script",
key,
);
process::exit(1);
})
}
|
