SeqCst->Relaxed for FIRST_PANIC.

m-ou-se · m-ou-se · commit 9f25a04498fb · 2024-03-19T15:27:11.000+01:00
Relaxed is enough to make sure this `swap` results in `true` only once.
diff --git a/library/std/src/panicking.rs b/library/std/src/panicking.rs
@@ -272,7 +272,7 @@ fn default_hook(info: &PanicInfo<'_>) {
                 drop(backtrace::print(err, crate::backtrace_rs::PrintFmt::Full))
             }
             Some(BacktraceStyle::Off) => {
-                if FIRST_PANIC.swap(false, Ordering::SeqCst) {
+                if FIRST_PANIC.swap(false, Ordering::Relaxed) {
                     let _ = writeln!(
                         err,
                         "note: run with `RUST_BACKTRACE=1` environment variable to display a \

Original file line number	Diff line number	Diff line change
`@@ -272,7 +272,7 @@ fn default_hook(info: &PanicInfo<'_>) {`
`272`	`272`	`drop(backtrace::print(err, crate::backtrace_rs::PrintFmt::Full))`
`273`	`273`	`}`
`274`	`274`	`Some(BacktraceStyle::Off) => {`
`275`		`- if FIRST_PANIC.swap(false, Ordering::SeqCst) {`
	`275`	`+ if FIRST_PANIC.swap(false, Ordering::Relaxed) {`
`276`	`276`	`let _ = writeln!(`
`277`	`277`	`err,`
`278`	`278`	"note: run with `RUST_BACKTRACE=1` environment variable to display a \