diff --git a/library/std/src/io/stdio.rs b/library/std/src/io/stdio.rs index 61ccc6f13c8..814e0dfda54 100644 --- a/library/std/src/io/stdio.rs +++ b/library/std/src/io/stdio.rs @@ -9,21 +9,24 @@ use crate::cell::RefCell; use crate::fmt; use crate::io::{self, BufReader, Initializer, IoSlice, IoSliceMut, LineWriter}; use crate::lazy::SyncOnceCell; +use crate::sync::atomic::{AtomicBool, Ordering}; use crate::sync::{Mutex, MutexGuard}; use crate::sys::stdio; use crate::sys_common; use crate::sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard}; use crate::thread::LocalKey; +static LOCAL_STREAMS: AtomicBool = AtomicBool::new(false); + thread_local! { - /// Stdout used by print! and println! macros + /// Used by the test crate to capture the output of the print! and println! macros. static LOCAL_STDOUT: RefCell>> = { RefCell::new(None) } } thread_local! { - /// Stderr used by eprint! and eprintln! macros, and panics + /// Used by the test crate to capture the output of the eprint! and eprintln! macros, and panics. static LOCAL_STDERR: RefCell>> = { RefCell::new(None) } @@ -890,10 +893,14 @@ impl fmt::Debug for StderrLock<'_> { #[doc(hidden)] pub fn set_panic(sink: Option>) -> Option> { use crate::mem; - LOCAL_STDERR.with(move |slot| mem::replace(&mut *slot.borrow_mut(), sink)).and_then(|mut s| { - let _ = s.flush(); - Some(s) - }) + let s = LOCAL_STDERR.with(move |slot| mem::replace(&mut *slot.borrow_mut(), sink)).and_then( + |mut s| { + let _ = s.flush(); + Some(s) + }, + ); + LOCAL_STREAMS.store(true, Ordering::Release); + s } /// Resets the thread-local stdout handle to the specified writer @@ -913,10 +920,14 @@ pub fn set_panic(sink: Option>) -> Option>) -> Option> { use crate::mem; - LOCAL_STDOUT.with(move |slot| mem::replace(&mut *slot.borrow_mut(), sink)).and_then(|mut s| { - let _ = s.flush(); - Some(s) - }) + let s = LOCAL_STDOUT.with(move |slot| mem::replace(&mut *slot.borrow_mut(), sink)).and_then( + |mut s| { + let _ = s.flush(); + Some(s) + }, + ); + LOCAL_STREAMS.store(true, Ordering::Release); + s } /// Write `args` to output stream `local_s` if possible, `global_s` @@ -937,20 +948,26 @@ fn print_to( ) where T: Write, { - let result = local_s - .try_with(|s| { - // 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) + let result = LOCAL_STREAMS + .load(Ordering::Acquire) + .then(|| { + local_s + .try_with(|s| { + // 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) + }) + .ok() }) - .unwrap_or_else(|_| global_s().write_fmt(args)); + .flatten() + .unwrap_or_else(|| global_s().write_fmt(args)); if let Err(e) = result { panic!("failed printing to {}: {}", label, e); diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index d03428dd082..410860b4a5d 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -226,6 +226,7 @@ #![feature(asm)] #![feature(associated_type_bounds)] #![feature(atomic_mut_ptr)] +#![feature(bool_to_option)] #![feature(box_syntax)] #![feature(c_variadic)] #![feature(cfg_accessible)]