From 78ab1f609a4fb2514d8223e8ce6bf9195c01b5d6 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Mon, 21 Dec 2020 18:23:47 -0700
Subject: [PATCH] apply kprotty's WaitGroup fix

---
 src/WaitGroup.zig | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/src/WaitGroup.zig b/src/WaitGroup.zig
index e5d4e600e2..6a0b12d050 100644
--- a/src/WaitGroup.zig
+++ b/src/WaitGroup.zig
@@ -32,19 +32,21 @@ pub fn stop(self: *WaitGroup) void {
 }
 
 pub fn wait(self: *WaitGroup) void {
-    const held = self.lock.acquire();
+    while (true) {
+        const held = self.lock.acquire();
+
+        if (self.counter == 0) {
+            held.release();
+            return;
+        }
+
+        var event = std.ResetEvent.init();
+        defer event.deinit();
+
+        std.debug.assert(self.event == null);
+        self.event = &event;
 
-    if (self.counter == 0) {
         held.release();
-        return;
+        event.wait();
     }
-
-    var event = std.ResetEvent.init();
-    defer event.deinit();
-
-    std.debug.assert(self.event == null);
-    self.event = &event;
-
-    held.release();
-    event.wait();
 }