| use std::env; |
| use std::fs; |
| use std::path::Path; |
| use std::process::{Command, ExitStatus, Stdio}; |
| use std::str; |
| |
| // This code exercises the surface area that we expect of the Error generic |
| // member access API. If the current toolchain is able to compile it, then |
| // thiserror is able to provide backtrace support. |
| const PROBE: &str = r#" |
| #![feature(error_generic_member_access)] |
| |
| use std::error::{Error, Request}; |
| use std::fmt::{self, Debug, Display}; |
| |
| struct MyError(Thing); |
| struct Thing; |
| |
| impl Debug for MyError { |
| fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result { |
| unimplemented!() |
| } |
| } |
| |
| impl Display for MyError { |
| fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result { |
| unimplemented!() |
| } |
| } |
| |
| impl Error for MyError { |
| fn provide<'a>(&'a self, request: &mut Request<'a>) { |
| request.provide_ref(&self.0); |
| } |
| } |
| "#; |
| |
| fn main() { |
| match compile_probe() { |
| Some(status) if status.success() => println!("cargo:rustc-cfg=error_generic_member_access"), |
| _ => {} |
| } |
| } |
| |
| fn compile_probe() -> Option<ExitStatus> { |
| 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 None; |
| } |
| |
| let rustc = env::var_os("RUSTC")?; |
| let out_dir = env::var_os("OUT_DIR")?; |
| let probefile = Path::new(&out_dir).join("probe.rs"); |
| fs::write(&probefile, PROBE).ok()?; |
| |
| // 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) |
| }; |
| |
| cmd.stderr(Stdio::null()) |
| .arg("--edition=2018") |
| .arg("--crate-name=thiserror_build") |
| .arg("--crate-type=lib") |
| .arg("--emit=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); |
| } |
| } |
| } |
| |
| cmd.status().ok() |
| } |