Update thread spawn hooks.

1. Make the effect thread local.
2. Don't return a io::Result from hooks.

1 files changed, 2 insertions, 5 deletions

diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs
index c6b1e0de84c..79621e7fa6b 100644
--- a/library/std/src/thread/mod.rs
+++ b/library/std/src/thread/mod.rs
@@ -491,7 +491,7 @@ impl Builder {
             None => Thread::new_unnamed(id),
         };
 
-        let hooks = spawnhook::run_spawn_hooks(&my_thread)?;
+        let hooks = spawnhook::run_spawn_hooks(&my_thread);
 
         let their_thread = my_thread.clone();
 
@@ -539,12 +539,9 @@ impl Builder {
                 imp::Thread::set_name(name);
             }
 
-            for hook in hooks {
-                hook();
-            }
-
             let f = f.into_inner();
             let try_result = panic::catch_unwind(panic::AssertUnwindSafe(|| {
+                crate::sys::backtrace::__rust_begin_short_backtrace(|| hooks.run());
                 crate::sys::backtrace::__rust_begin_short_backtrace(f)
             }));
             // SAFETY: `their_packet` as been built just above and moved by the