revert change to see if it help ci failure

Author: hymm

crates/bevy_tasks/src/task_pool.rs

@@ -3,7 +3,7 @@ use std::{
     marker::PhantomData,
     mem,
     sync::Arc,
-    thread::{self, JoinHandle},
+    thread::{self, JoinHandle}, pin::Pin,
 };
 
 use async_task::FallibleTask;
@@ -279,8 +279,23 @@ impl TaskPool {
             // Pin the futures on the stack.
             pin!(get_results);
 
+            // SAFETY: This function blocks until all futures complete, so we do not read/write
+            // the data from futures outside of the 'scope lifetime. However,
+            // rust has no way of knowing this so we must convert to 'static
+            // here to appease the compiler as it is unable to validate safety.
+            let get_results: Pin<&mut (dyn Future<Output = Vec<T>> + 'static + Send)> = get_results;
+            let get_results: Pin<&'static mut (dyn Future<Output = Vec<T>> + 'static + Send)> =
+                unsafe { mem::transmute(get_results) };
+
+            // The thread that calls scope() will participate in driving tasks in the pool
+            // forward until the tasks that are spawned by this scope() call
+            // complete. (If the caller of scope() happens to be a thread in
+            // this thread pool, and we only have one thread in the pool, then
+            // simply calling future::block_on(spawned) would deadlock.)
+            let mut spawned = task_scope_executor.spawn(get_results);
+
             loop {
-                if let Some(result) = future::block_on(future::poll_once(&mut get_results)) {
+                if let Some(result) = future::block_on(future::poll_once(&mut spawned)) {
                     break result;
                 };