From b628238f541810705c35f42900fa6cd1984a4a7b Mon Sep 17 00:00:00 2001
From: Robert Yokota <rayokota@gmail.com>
Date: Wed, 10 Sep 2025 14:55:59 -0700
Subject: [PATCH 1/3] Add better Avro validation

---
 schemaregistry/serde/avro.ts           |  9 +++++++-
 schemaregistry/test/serde/avro.spec.ts | 29 ++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/schemaregistry/serde/avro.ts b/schemaregistry/serde/avro.ts
index 984d8bfb..43ebb946 100644
--- a/schemaregistry/serde/avro.ts
+++ b/schemaregistry/serde/avro.ts
@@ -3,7 +3,7 @@ import {
   FieldTransform,
   FieldType, Migration, RefResolver,
   RuleConditionError,
-  RuleContext, SchemaId, SerdeType,
+  RuleContext, SchemaId, SerdeType, SerializationError,
   Serializer, SerializerConfig
 } from "./serde";
 import {
@@ -93,6 +93,13 @@ export class AvroSerializer extends Serializer implements AvroSerde {
     const subject = this.subjectName(topic, info)
     msg = await this.executeRules(
       subject, topic, RuleMode.WRITE, null, info, msg, getInlineTags(info, deps))
+    if (!avroType.isValid(msg, {errorHook: (path, any, type) => {
+      throw new SerializationError(
+        `Invalid message at ${path.join('.')}, expected ${type}, got ${stringify(any)}`)
+    }})) {
+      throw new SerializationError(
+        `Invalid message, expected ${avroType}, got ${stringify(msg)}`)
+    }
     let msgBytes = avroType.toBuffer(msg)
     msgBytes = await this.executeRulesWithPhase(
       subject, topic, RulePhase.ENCODING, RuleMode.WRITE, null, info, msgBytes, null)
diff --git a/schemaregistry/test/serde/avro.spec.ts b/schemaregistry/test/serde/avro.spec.ts
index 7580939e..a48e21c1 100644
--- a/schemaregistry/test/serde/avro.spec.ts
+++ b/schemaregistry/test/serde/avro.spec.ts
@@ -75,6 +75,18 @@ const demoSchema = `
   ]
 }
 `
+const nameSchema = `
+{
+  "type": "record",
+  "namespace": "examples",
+  "name": "NameSchema",
+  "fields": [
+    { "name": "fullName", "type": "string" },
+    { "name": "lastName", "type": "string" }
+  ],
+  "version": "1"
+}
+`
 const demoSchemaSingleTag = `
 {
   "name": "DemoSchema",
@@ -369,6 +381,23 @@ describe('AvroSerializer', () => {
     expect(obj2.boolField).toEqual(obj.boolField);
     expect(obj2.bytesField).toEqual(obj.bytesField);
   })
+  it('bad serialization', async () => {
+    const conf: ClientConfig = {
+      baseURLs: [baseURL]
+    };
+    const client = SchemaRegistryClient.newClient(conf);
+    const ser = new AvroSerializer(client, SerdeType.VALUE, { useLatestVersion: true });
+    const info = {
+      schemaType: 'AVRO',
+      schema: nameSchema
+    };
+    await client.register(subject, info, false);
+    try {
+      await ser.serialize(topic, { lastName: "lastName" });
+    } catch (err) {
+      expect(err).toBeInstanceOf(SerializationError)
+    }
+  })
   it('guid in header', async () => {
     let conf: ClientConfig = {
       baseURLs: [baseURL],

From f299bc6b33821b4a9a1eff14b54d9dbc13ca11db Mon Sep 17 00:00:00 2001
From: Robert Yokota <rayokota@gmail.com>
Date: Wed, 10 Sep 2025 14:59:20 -0700
Subject: [PATCH 2/3] Minor cleanup

---
 schemaregistry/serde/avro.ts | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/schemaregistry/serde/avro.ts b/schemaregistry/serde/avro.ts
index 43ebb946..54bc262f 100644
--- a/schemaregistry/serde/avro.ts
+++ b/schemaregistry/serde/avro.ts
@@ -93,13 +93,10 @@ export class AvroSerializer extends Serializer implements AvroSerde {
     const subject = this.subjectName(topic, info)
     msg = await this.executeRules(
       subject, topic, RuleMode.WRITE, null, info, msg, getInlineTags(info, deps))
-    if (!avroType.isValid(msg, {errorHook: (path, any, type) => {
+    avroType.isValid(msg, {errorHook: (path, any, type) => {
       throw new SerializationError(
         `Invalid message at ${path.join('.')}, expected ${type}, got ${stringify(any)}`)
-    }})) {
-      throw new SerializationError(
-        `Invalid message, expected ${avroType}, got ${stringify(msg)}`)
-    }
+    }})
     let msgBytes = avroType.toBuffer(msg)
     msgBytes = await this.executeRulesWithPhase(
       subject, topic, RulePhase.ENCODING, RuleMode.WRITE, null, info, msgBytes, null)

From 39da52dbb762678a14b3b36428ba2f5adb278cea Mon Sep 17 00:00:00 2001
From: Robert Yokota <rayokota@gmail.com>
Date: Wed, 10 Sep 2025 15:21:15 -0700
Subject: [PATCH 3/3] Minor cleanup

---
 schemaregistry/test/serde/avro.spec.ts | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/schemaregistry/test/serde/avro.spec.ts b/schemaregistry/test/serde/avro.spec.ts
index a48e21c1..7d450af3 100644
--- a/schemaregistry/test/serde/avro.spec.ts
+++ b/schemaregistry/test/serde/avro.spec.ts
@@ -382,18 +382,19 @@ describe('AvroSerializer', () => {
     expect(obj2.bytesField).toEqual(obj.bytesField);
   })
   it('bad serialization', async () => {
-    const conf: ClientConfig = {
-      baseURLs: [baseURL]
-    };
-    const client = SchemaRegistryClient.newClient(conf);
-    const ser = new AvroSerializer(client, SerdeType.VALUE, { useLatestVersion: true });
-    const info = {
+    let conf: ClientConfig = {
+      baseURLs: [baseURL],
+      cacheCapacity: 1000
+    }
+    let client = SchemaRegistryClient.newClient(conf)
+    let ser = new AvroSerializer(client, SerdeType.VALUE, {useLatestVersion: true})
+    let info = {
       schemaType: 'AVRO',
       schema: nameSchema
-    };
-    await client.register(subject, info, false);
+    }
+    await client.register(subject, info, false)
     try {
-      await ser.serialize(topic, { lastName: "lastName" });
+      await ser.serialize(topic, { lastName: "lastName" })
     } catch (err) {
       expect(err).toBeInstanceOf(SerializationError)
     }