std: don't abort in thread::set_current

Author: joboet

library/std/src/thread/mod.rs

@@ -684,14 +684,11 @@ thread_local! {
 
 /// Sets the thread handle for the current thread.
 ///
-/// Aborts if the handle has been set already to reduce code size.
+/// Does nothing if the thread was already set. This can only happen if some code
+/// runs pre-main, but it seems unnecessary to detect that, especially since
+/// adding `.unwrap()` here can add ~3kB to the binary size.
 pub(crate) fn set_current(thread: Thread) {
-    // Using `unwrap` here can add ~3kB to the binary size. We have complete
-    // control over where this is called, so just abort if there is a bug.
-    CURRENT.with(|current| match current.set(thread) {
-        Ok(()) => {}
-        Err(_) => rtabort!("should only be set once"),
-    });
+    let _ = CURRENT.with(|current| current.set(thread));
 }
 
 /// Gets a handle to the thread that invokes it.