From d6eac54ccfa69220f7a3b78c391ec336e9bedf46 Mon Sep 17 00:00:00 2001
From: Jake Wharton <jw@squareup.com>
Date: Wed, 27 Mar 2024 10:45:03 -0400
Subject: [PATCH] Make optional converter public

---
 CHANGELOG.md                                  |  2 +-
 .../retrofit2/OptionalConverterFactory.java   | 19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 511a9e0516..ce0e77c017 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,7 +8,7 @@
 
 **Changed**
 
- - Nothing yet!
+ - The built-in `OptionalConverterFactory` is now public to allow installing it before other converters which consume all types (e.g., Moshi, Gson, Jackson, etc.).
 
 **Fixed**
 
diff --git a/retrofit/src/main/java/retrofit2/OptionalConverterFactory.java b/retrofit/src/main/java/retrofit2/OptionalConverterFactory.java
index 4c628b7c7c..6d50c83e32 100644
--- a/retrofit/src/main/java/retrofit2/OptionalConverterFactory.java
+++ b/retrofit/src/main/java/retrofit2/OptionalConverterFactory.java
@@ -25,9 +25,24 @@
 import okhttp3.ResponseBody;
 import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement;
 
+/**
+ * A {@link Converter.Factory} which supports Java's {@link Optional} to wrap null values from
+ * another converter.
+ * <p>
+ * This factory is installed by default on the JVM and Android API 24+. If you are using another
+ * converter which tries to serialize all types, such as Moshi or Gson, the default installation
+ * of this factory never gets a chance to run. To work around this, you can explicitly install this
+ * factory before your serialization library converter.
+ */
 @IgnoreJRERequirement // Only added when Optional is available (Java 8+ / Android API 24+).
 @TargetApi(24)
-final class OptionalConverterFactory extends Converter.Factory {
+public final class OptionalConverterFactory extends Converter.Factory {
+  public static OptionalConverterFactory create() {
+    return new OptionalConverterFactory();
+  }
+
+  OptionalConverterFactory() {}
+
   @Override
   public @Nullable Converter<ResponseBody, ?> responseBodyConverter(
       Type type, Annotation[] annotations, Retrofit retrofit) {
@@ -43,7 +58,7 @@ final class OptionalConverterFactory extends Converter.Factory {
 
   @IgnoreJRERequirement
   static final class OptionalConverter<T> implements Converter<ResponseBody, Optional<T>> {
-    final Converter<ResponseBody, T> delegate;
+    private final Converter<ResponseBody, T> delegate;
 
     OptionalConverter(Converter<ResponseBody, T> delegate) {
       this.delegate = delegate;