95 lines
2.6 KiB
Rust
95 lines
2.6 KiB
Rust
use std::env;
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use std::fs;
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use std::path::Path;
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use std::process::{Command, ExitStatus, Stdio};
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use std::str;
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// This code exercises the surface area that we expect of the Error generic
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// member access API. If the current toolchain is able to compile it, then
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// thiserror is able to provide backtrace support.
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const PROBE: &str = r#"
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#![feature(error_generic_member_access)]
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use std::error::{Error, Request};
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use std::fmt::{self, Debug, Display};
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struct MyError(Thing);
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struct Thing;
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impl Debug for MyError {
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fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
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unimplemented!()
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}
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}
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impl Display for MyError {
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fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
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unimplemented!()
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}
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}
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impl Error for MyError {
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fn provide<'a>(&'a self, request: &mut Request<'a>) {
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request.provide_ref(&self.0);
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}
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}
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"#;
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fn main() {
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match compile_probe() {
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Some(status) if status.success() => println!("cargo:rustc-cfg=error_generic_member_access"),
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_ => {}
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}
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}
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fn compile_probe() -> Option<ExitStatus> {
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if env::var_os("RUSTC_STAGE").is_some() {
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// We are running inside rustc bootstrap. This is a highly non-standard
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// environment with issues such as:
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//
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// https://github.com/rust-lang/cargo/issues/11138
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// https://github.com/rust-lang/rust/issues/114839
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//
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// Let's just not use nightly features here.
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return None;
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}
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let rustc = env::var_os("RUSTC")?;
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let out_dir = env::var_os("OUT_DIR")?;
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let probefile = Path::new(&out_dir).join("probe.rs");
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fs::write(&probefile, PROBE).ok()?;
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// Make sure to pick up Cargo rustc configuration.
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let mut cmd = if let Some(wrapper) = env::var_os("RUSTC_WRAPPER") {
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let mut cmd = Command::new(wrapper);
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// The wrapper's first argument is supposed to be the path to rustc.
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cmd.arg(rustc);
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cmd
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} else {
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Command::new(rustc)
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};
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cmd.stderr(Stdio::null())
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.arg("--edition=2018")
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.arg("--crate-name=thiserror_build")
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.arg("--crate-type=lib")
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.arg("--emit=metadata")
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.arg("--out-dir")
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.arg(out_dir)
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.arg(probefile);
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if let Some(target) = env::var_os("TARGET") {
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cmd.arg("--target").arg(target);
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}
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// If Cargo wants to set RUSTFLAGS, use that.
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if let Ok(rustflags) = env::var("CARGO_ENCODED_RUSTFLAGS") {
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if !rustflags.is_empty() {
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for arg in rustflags.split('\x1f') {
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cmd.arg(arg);
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}
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}
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}
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cmd.status().ok()
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}
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