From 2637311ef59a5f53c8f19c1b565d73f2b063b276 Mon Sep 17 00:00:00 2001
From: CalDescent <caldescent@protonmail.com>
Date: Wed, 9 Feb 2022 20:20:30 +0000
Subject: [PATCH] Prevent potential ConcurrentModificationException in the
 build queue

---
 .../arbitrary/ArbitraryDataBuilderThread.java        | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/main/java/org/qortal/controller/arbitrary/ArbitraryDataBuilderThread.java b/src/main/java/org/qortal/controller/arbitrary/ArbitraryDataBuilderThread.java
index f6c14669..1c03daed 100644
--- a/src/main/java/org/qortal/controller/arbitrary/ArbitraryDataBuilderThread.java
+++ b/src/main/java/org/qortal/controller/arbitrary/ArbitraryDataBuilderThread.java
@@ -36,11 +36,15 @@ public class ArbitraryDataBuilderThread implements Runnable {
                     continue;
                 }
 
+                Map.Entry<String, ArbitraryDataBuildQueueItem> next = null;
+
                 // Find resources that are queued for building
-                Map.Entry<String, ArbitraryDataBuildQueueItem> next = buildManager.arbitraryDataBuildQueue
-                        .entrySet().stream()
-                        .filter(e -> e.getValue().isQueued())
-                        .findFirst().orElse(null);
+                synchronized (buildManager.arbitraryDataBuildQueue) {
+                    next = buildManager.arbitraryDataBuildQueue
+                            .entrySet().stream()
+                            .filter(e -> e.getValue().isQueued())
+                            .findFirst().orElse(null);
+                }
 
                 if (next == null) {
                     continue;