From 67bc47181c82d3cc5b3ad3ceb77acc6451b29bca Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Thu, 15 Jun 2023 22:24:58 -0400
Subject: [PATCH] fix: in blocking queue, `pop` works on a non empty closed
 queue

---
 src/bb_queue.ml | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/bb_queue.ml b/src/bb_queue.ml
index 1cec05db..df23d980 100644
--- a/src/bb_queue.ml
+++ b/src/bb_queue.ml
@@ -37,10 +37,12 @@ let push (self : _ t) x : unit =
 let pop (self : 'a t) : 'a =
   Mutex.lock self.mutex;
   let rec loop () =
-    if self.closed then (
-      Mutex.unlock self.mutex;
-      raise Closed
-    ) else if Queue.is_empty self.q then (
+    if Queue.is_empty self.q then (
+      if self.closed then (
+        Mutex.unlock self.mutex;
+        raise Closed
+      );
+
       Condition.wait self.cond self.mutex;
       (loop [@tailcall]) ()
     ) else (