native: Protect against spurious wakeups on cvars

This is a very real problem with cvars on normal systems, and all of channels
will not work if spurious wakeups are accepted. This problem is just solved with
a synchronized flag (accessed in the cvar's lock) to see whether a signal()
actually happened or whether it's spurious.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstd/comm/mod.rs b/src/libstd/comm/mod.rs
index 7b464bc2f32..ae440894b4e 100644
--- a/src/libstd/comm/mod.rs
+++ b/src/libstd/comm/mod.rs
@@ -875,7 +875,7 @@ impl<T: Send> Port<T> {
         let data = self.try_recv_inc(false);
         if data.is_none() &&
            unsafe { (*packet).cnt.load(SeqCst) } != DISCONNECTED {
-            fail!("bug: woke up too soon");
+            fail!("bug: woke up too soon {}", unsafe { (*packet).cnt.load(SeqCst) });
         }
         return data;
     }