diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs index d410faca30d9e..0fb0757792ed7 100644 --- a/src/libstd/io/stdio.rs +++ b/src/libstd/io/stdio.rs @@ -792,10 +792,14 @@ fn print_to( { let result = local_s .try_with(|s| { - if let Ok(mut borrowed) = s.try_borrow_mut() { - if let Some(w) = borrowed.as_mut() { - return w.write_fmt(args); - } + // Note that we completely remove a local sink to write to in case + // our printing recursively panics/prints, so the recursive + // panic/print goes to the global sink instead of our local sink. + let prev = s.borrow_mut().take(); + if let Some(mut w) = prev { + let result = w.write_fmt(args); + *s.borrow_mut() = Some(w); + return result; } global_s().write_fmt(args) }) diff --git a/src/test/ui/panic-while-printing.rs b/src/test/ui/panic-while-printing.rs new file mode 100644 index 0000000000000..7e9fa16b0847a --- /dev/null +++ b/src/test/ui/panic-while-printing.rs @@ -0,0 +1,24 @@ +// run-pass +// ignore-emscripten no subprocess support + +#![feature(set_stdio)] + +use std::fmt; +use std::fmt::{Display, Formatter}; +use std::io::set_panic; + +pub struct A; + +impl Display for A { + fn fmt(&self, _f: &mut Formatter<'_>) -> fmt::Result { + panic!(); + } +} + +fn main() { + set_panic(Some(Box::new(Vec::new()))); + assert!(std::panic::catch_unwind(|| { + eprintln!("{}", A); + }) + .is_err()); +} diff --git a/src/test/ui/test-panic-while-printing.rs b/src/test/ui/test-panic-while-printing.rs new file mode 100644 index 0000000000000..23f45407c1af3 --- /dev/null +++ b/src/test/ui/test-panic-while-printing.rs @@ -0,0 +1,24 @@ +// compile-flags:--test +// run-pass +// ignore-emscripten no subprocess support + +use std::fmt; +use std::fmt::{Display, Formatter}; + +pub struct A(Vec); + +impl Display for A { + fn fmt(&self, _f: &mut Formatter<'_>) -> fmt::Result { + self.0[0]; + Ok(()) + } +} + +#[test] +fn main() { + let result = std::panic::catch_unwind(|| { + let a = A(vec![]); + eprintln!("{}", a); + }); + assert!(result.is_err()); +}