From d3080ee3f09df446c1ab8ef9909394eae777f386 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Sumis=C5=82awski?=
 <rafal.sumislawski@gmail.com>
Date: Sun, 21 Feb 2021 21:01:23 +0100
Subject: [PATCH] synchronise access to stamps in testQuickFilter

---
 main/src/main/scala/sbt/Defaults.scala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index d8c9fedaf..033bbeb6e 100644
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -1375,7 +1375,7 @@ object Defaults extends BuildCommon {
       }
       def noSuccessYet(test: String) = succeeded.get(test) match {
         case None     => true
-        case Some(ts) => stamp(test) > ts
+        case Some(ts) => stamps.synchronized(stamp(test)) > ts
       }
       args =>
         for (filter <- selectedFilter(args))