From 3af1a89c926c07c2a9d11edccdcfb798e898e9bf Mon Sep 17 00:00:00 2001
From: ashley-taylor <ashley.taylor@phocassoftware.com>
Date: Mon, 21 Jul 2025 14:12:40 +1200
Subject: [PATCH] AVRO-4169 fix bug with custom encoder

---
 .../org/apache/avro/reflect/ReflectData.java  |  8 +++++++
 .../apache/avro/reflect/TestAvroEncode.java   | 21 ++++++++++---------
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectData.java b/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectData.java
index 4b993c6fddc..916c15efbf9 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectData.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectData.java
@@ -683,6 +683,14 @@ protected Schema createSchema(Type type, Map<String, Schema> names) {
         setElement(result, component);
         return result;
       }
+      AvroEncode enc = ReflectionUtil.getAvroEncode(c);
+      if (enc != null) {
+        try {
+          return enc.using().getDeclaredConstructor().newInstance().getSchema();
+        } catch (Exception e) {
+          throw new AvroRuntimeException("Could not create schema from custom serializer for " + c.getName());
+        }
+      }
       AvroSchema explicit = c.getAnnotation(AvroSchema.class);
       if (explicit != null) // explicit schema
         return new Schema.Parser().parse(explicit.value());
diff --git a/lang/java/avro/src/test/java/org/apache/avro/reflect/TestAvroEncode.java b/lang/java/avro/src/test/java/org/apache/avro/reflect/TestAvroEncode.java
index daee2a39a96..7da7170e1b6 100644
--- a/lang/java/avro/src/test/java/org/apache/avro/reflect/TestAvroEncode.java
+++ b/lang/java/avro/src/test/java/org/apache/avro/reflect/TestAvroEncode.java
@@ -37,23 +37,23 @@ public class TestAvroEncode {
   @Test
   void testWithinClass() throws IOException {
 
-    var wrapper = new Wrapper(new R1("test"));
+    var wrapper = new Wrapper(new R1("321"));
 
     var read = readWrite(wrapper);
 
-    assertEquals("test", wrapper.getR1().getValue());
-    assertEquals("test used this", read.getR1().getValue());
+    assertEquals("321", wrapper.getR1().getValue());
+    assertEquals("321 used this", read.getR1().getValue());
   }
 
   @Test
   void testDirect() throws IOException {
 
-    var r1 = new R1("test");
+    var r1 = new R1("123");
 
     var read = readWrite(r1);
 
-    assertEquals("test", r1.getValue());
-    assertEquals("test used this", read.getValue());
+    assertEquals("123", r1.getValue());
+    assertEquals("123 used this", read.getValue());
   }
 
   @Test
@@ -127,14 +127,15 @@ public String getValue() {
   public static class R1Encoding extends CustomEncoding<R1> {
 
     {
-      schema = Schema.createRecord("R1", null, null, false,
-          Arrays.asList(new Schema.Field("value", Schema.create(Schema.Type.STRING), null, null)));
+      schema = Schema.createRecord("R1", null, "org.apache.avro.reflect.TestAvroEncode", false,
+          Arrays.asList(new Schema.Field("value", Schema.create(Schema.Type.INT), null, null)));
     }
 
     @Override
     protected void write(Object datum, Encoder out) throws IOException {
       if (datum instanceof R1) {
-        out.writeString(((R1) datum).getValue());
+        var value = ((R1) datum).getValue();
+        out.writeInt(Integer.parseInt(value));
       } else {
         throw new AvroTypeException("Expected R1, got " + datum.getClass());
       }
@@ -143,7 +144,7 @@ protected void write(Object datum, Encoder out) throws IOException {
 
     @Override
     protected R1 read(Object reuse, Decoder in) throws IOException {
-      return new R1(in.readString() + " used this");
+      return new R1(in.readInt() + " used this");
     }
   }