5edaa7eefd
This commit fixes an issue where if `eprintln!` is used in a TLS destructor it can accidentally cause the process to abort. TLS destructors are executed after `main` returns on the main thread, and at this point we've also deinitialized global `Lazy` values like those which store the `Stderr` and `Stdout` internals. This means that despite handling TLS not being accessible in `eprintln!`, we will fail due to not being able to call `stderr()`. This means that we'll double-panic quickly because panicking also attempt to write to stderr. The fix here is to reimplement the global stderr handle to avoid the need for destruction. This avoids the need for `Lazy` as well as the hidden panic inside of the `stderr` function. Overall this should improve the robustness of printing errors and/or panics in weird situations, since the `stderr` accessor should be infallible in more situations.
49 lines
1023 B
Rust
49 lines
1023 B
Rust
// run-pass
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// ignore-emscripten no processes
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use std::cell::RefCell;
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use std::env;
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use std::process::Command;
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fn main() {
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let name = "YOU_ARE_THE_TEST";
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if env::var(name).is_ok() {
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std::thread::spawn(|| {
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TLS.with(|f| f.borrow().ensure());
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})
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.join()
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.unwrap();
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} else {
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let me = env::current_exe().unwrap();
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let output = Command::new(&me).env(name, "1").output().unwrap();
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println!("{:?}", output);
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assert!(output.status.success());
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let stderr = String::from_utf8(output.stderr).unwrap();
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assert!(stderr.contains("hello new\n"));
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assert!(stderr.contains("hello drop\n"));
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}
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}
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struct Stuff {
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_x: usize,
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}
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impl Stuff {
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fn new() -> Self {
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eprintln!("hello new");
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Self { _x: 0 }
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}
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fn ensure(&self) {}
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}
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impl Drop for Stuff {
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fn drop(&mut self) {
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eprintln!("hello drop");
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}
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}
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thread_local! {
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static TLS: RefCell<Stuff> = RefCell::new(Stuff::new());
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}
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