1 files changed, 53 insertions, 0 deletions
diff --git a/patches/api/0195-Make-JavaPluginLoader-thread-safe.patch b/patches/api/0195-Make-JavaPluginLoader-thread-safe.patch
new file mode 100644
index 0000000000..be66a6a695
--- /dev/null
+++ b/patches/api/0195-Make-JavaPluginLoader-thread-safe.patch
@@ -0,0 +1,53 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Trigary <[email protected]>
+Date: Wed, 15 Apr 2020 01:24:55 -0400
+Subject: [PATCH] Make JavaPluginLoader thread-safe
+
+
+diff --git a/src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java b/src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java
+index f26303315c9c93356f0b04440136855dd54d32b7..ce751577623eaad0f31e2eb7bf0842d1ab73e845 100644
+--- a/src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java
++++ b/src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java
+@@ -52,6 +52,8 @@ import org.yaml.snakeyaml.error.YAMLException;
+ public final class JavaPluginLoader implements PluginLoader {
+     final Server server;
+     private final Pattern[] fileFilters = new Pattern[]{Pattern.compile("\\.jar$")};
++    private final Map<String, java.util.concurrent.locks.ReentrantReadWriteLock> classLoadLock = new java.util.HashMap<String, java.util.concurrent.locks.ReentrantReadWriteLock>(); // Paper
++    private final Map<String, Integer> classLoadLockCount = new java.util.HashMap<String, Integer>(); // Paper
+     private final List<PluginClassLoader> loaders = new CopyOnWriteArrayList<PluginClassLoader>();
+     private final LibraryLoader libraryLoader;
+ 
+@@ -201,12 +203,33 @@ public final class JavaPluginLoader implements PluginLoader {
+ 
+     @Nullable
+     Class<?> getClassByName(final String name, boolean resolve, PluginDescriptionFile description) {
++        // Paper start - make MT safe
++        java.util.concurrent.locks.ReentrantReadWriteLock lock;
++        synchronized (classLoadLock) {
++            lock = classLoadLock.computeIfAbsent(name, (x) -> new java.util.concurrent.locks.ReentrantReadWriteLock());
++            classLoadLockCount.compute(name, (x, prev) -> prev != null ? prev + 1 : 1);
++        }
++        lock.writeLock().lock();try {
++        // Paper end
+         for (PluginClassLoader loader : loaders) {
+             try {
+                 return loader.loadClass0(name, resolve, false, ((SimplePluginManager) server.getPluginManager()).isTransitiveDepend(description, loader.plugin.getDescription()));
+             } catch (ClassNotFoundException cnfe) {
+             }
+         }
++        // Paper start - make MT safe
++        } finally {
++            synchronized (classLoadLock) {
++                lock.writeLock().unlock();
++                if (classLoadLockCount.get(name) == 1) {
++                    classLoadLock.remove(name);
++                    classLoadLockCount.remove(name);
++                } else {
++                    classLoadLockCount.compute(name, (x, prev) -> prev - 1);
++                }
++            }
++        }
++        // Paper end
+         return null;
+     }
+