From 9a9d502d682439ba20859073146924bf826f3a37 Mon Sep 17 00:00:00 2001
From: Marcono1234 <Marcono1234@users.noreply.github.com>
Date: Sat, 25 Sep 2021 00:30:17 +0200
Subject: [PATCH 1/2] Improve TreeTypeAdapter thread-safety

Gson claims to be thread-safe so TreeTypeAdapter.delegate() might be
called by multiple threads. To guarantee that each thread sees a fully
constructed `delegate`, the field has to be `volatile`.
---
 .../java/com/google/gson/internal/bind/TreeTypeAdapter.java    | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java b/gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java
index a5c6c5dcda..bc26ea8898 100644
--- a/gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java
+++ b/gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java
@@ -47,7 +47,7 @@ public final class TreeTypeAdapter<T> extends TypeAdapter<T> {
   private final GsonContextImpl context = new GsonContextImpl();
 
   /** The delegate is lazily created because it may not be needed, and creating it may fail. */
-  private TypeAdapter<T> delegate;
+  private volatile TypeAdapter<T> delegate;
 
   public TreeTypeAdapter(JsonSerializer<T> serializer, JsonDeserializer<T> deserializer,
       Gson gson, TypeToken<T> typeToken, TypeAdapterFactory skipPast) {
@@ -83,6 +83,7 @@ public TreeTypeAdapter(JsonSerializer<T> serializer, JsonDeserializer<T> deseria
   }
 
   private TypeAdapter<T> delegate() {
+    // Allows racy initialization of `delegate` by multiple threads
     TypeAdapter<T> d = delegate;
     return d != null
         ? d

From c316f7d7e223509575d915a3f316ccb863cb1171 Mon Sep 17 00:00:00 2001
From: Marcono1234 <Marcono1234@users.noreply.github.com>
Date: Wed, 29 Sep 2021 00:34:35 +0200
Subject: [PATCH 2/2] Improve TreeTypeAdapter thread race comment

---
 .../java/com/google/gson/internal/bind/TreeTypeAdapter.java     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java b/gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java
index bc26ea8898..03dfc32631 100644
--- a/gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java
+++ b/gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java
@@ -83,7 +83,7 @@ public TreeTypeAdapter(JsonSerializer<T> serializer, JsonDeserializer<T> deseria
   }
 
   private TypeAdapter<T> delegate() {
-    // Allows racy initialization of `delegate` by multiple threads
+    // A race might lead to `delegate` being assigned by multiple threads but the last assignment will stick
     TypeAdapter<T> d = delegate;
     return d != null
         ? d