From dc96331c49985f264c7d129ca3d5604889eddd79 Mon Sep 17 00:00:00 2001
From: James Watkins-Harvey <james.watkinsharvey@temporal.io>
Date: Fri, 22 May 2026 17:40:00 -0400
Subject: [PATCH] fix: handle bytes in map and repeated fields in toProto3JSON

---
 .../test-fixtures/proto/test.json             | 10 +++++++++
 .../test-fixtures/proto/test.proto            |  2 ++
 .../typescript/src/toproto3json.ts            |  7 +++----
 .../typescript/test/unit/map.ts               | 10 +++++++++
 .../typescript/test/unit/repeated.ts          | 21 +++++++++++++++++++
 5 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/core/packages/proto3-json-serializer-nodejs/test-fixtures/proto/test.json b/core/packages/proto3-json-serializer-nodejs/test-fixtures/proto/test.json
index e107366b32af..5f9a37c68f3f 100644
--- a/core/packages/proto3-json-serializer-nodejs/test-fixtures/proto/test.json
+++ b/core/packages/proto3-json-serializer-nodejs/test-fixtures/proto/test.json
@@ -91,6 +91,11 @@
               "keyType": "string",
               "type": "Enum",
               "id": 6
+            },
+            "bytesMapField": {
+              "keyType": "string",
+              "type": "bytes",
+              "id": 7
             }
           }
         },
@@ -128,6 +133,11 @@
               "rule": "repeated",
               "type": "Enum",
               "id": 7
+            },
+            "repeatedBytes": {
+              "rule": "repeated",
+              "type": "bytes",
+              "id": 8
             }
           }
         },
diff --git a/core/packages/proto3-json-serializer-nodejs/test-fixtures/proto/test.proto b/core/packages/proto3-json-serializer-nodejs/test-fixtures/proto/test.proto
index a2cf06ff9cc8..0884d119f592 100644
--- a/core/packages/proto3-json-serializer-nodejs/test-fixtures/proto/test.proto
+++ b/core/packages/proto3-json-serializer-nodejs/test-fixtures/proto/test.proto
@@ -56,6 +56,7 @@ message MessageWithMap {
     map<string, string> string_map_field = 4;
     map<string, int64> long_map_field = 5;
     map<string, Enum> enum_map_field = 6;
+    map<string, bytes> bytes_map_field = 7;
 }
 
 message MapValue {
@@ -68,6 +69,7 @@ message MessageWithRepeated {
     repeated string one_more_repeated_string = 5;
     repeated int64 repeated_long = 6;
     repeated Enum repeated_enum = 7;
+    repeated bytes repeated_bytes = 8;
 }
 
 message RepeatedValue {
diff --git a/core/packages/proto3-json-serializer-nodejs/typescript/src/toproto3json.ts b/core/packages/proto3-json-serializer-nodejs/typescript/src/toproto3json.ts
index 3a441193fa6f..affeee3dad6d 100644
--- a/core/packages/proto3-json-serializer-nodejs/typescript/src/toproto3json.ts
+++ b/core/packages/proto3-json-serializer-nodejs/typescript/src/toproto3json.ts
@@ -47,6 +47,9 @@ function convertSingleValue(value: JSONValue | object): JSONValue {
     if (value?.constructor?.name === 'Long') {
       return (value as LongStub).toString();
     }
+    if (Buffer.isBuffer(value) || value instanceof Uint8Array) {
+      return bytesToProto3JSON(value);
+    }
     throw new Error(`toProto3JSON: don't know how to convert value ${value}`);
   }
   return value;
@@ -200,10 +203,6 @@ export function toProto3JSON(
       result[key] = value;
       continue;
     }
-    if (Buffer.isBuffer(value) || value instanceof Uint8Array) {
-      result[key] = bytesToProto3JSON(value);
-      continue;
-    }
     result[key] = convertSingleValue(value);
     continue;
   }
diff --git a/core/packages/proto3-json-serializer-nodejs/typescript/test/unit/map.ts b/core/packages/proto3-json-serializer-nodejs/typescript/test/unit/map.ts
index 05aa1ef60b6c..718c0622f2ea 100644
--- a/core/packages/proto3-json-serializer-nodejs/typescript/test/unit/map.ts
+++ b/core/packages/proto3-json-serializer-nodejs/typescript/test/unit/map.ts
@@ -40,6 +40,10 @@ function testMap(root: protobuf.Root) {
       'minus one': '-1',
       zero: '0',
     },
+    bytesMapField: {
+      key1: 'dmFsdWUgMQo=',
+      key2: 'dmFsdWUgMgo=',
+    },
   });
   const json = {
     mapField: {
@@ -61,6 +65,10 @@ function testMap(root: protobuf.Root) {
       zero: '0',
     },
     enumMapField: {},
+    bytesMapField: {
+      key1: 'dmFsdWUgMQo=',
+      key2: 'dmFsdWUgMgo=',
+    },
   };
 
   it('serializes to proto3 JSON', () => {
@@ -90,6 +98,7 @@ function testEnumMap(root: protobuf.Root) {
       key1: 'UNKNOWN',
       key2: 'KNOWN',
     },
+    bytesMapField: {},
   };
   const jsonWithNumericEnums = {
     mapField: {},
@@ -99,6 +108,7 @@ function testEnumMap(root: protobuf.Root) {
       key1: 0,
       key2: 1,
     },
+    bytesMapField: {},
   };
 
   it('serializes to proto3 JSON with string enums', () => {
diff --git a/core/packages/proto3-json-serializer-nodejs/typescript/test/unit/repeated.ts b/core/packages/proto3-json-serializer-nodejs/typescript/test/unit/repeated.ts
index 2df7cac67334..00d59b72dc92 100644
--- a/core/packages/proto3-json-serializer-nodejs/typescript/test/unit/repeated.ts
+++ b/core/packages/proto3-json-serializer-nodejs/typescript/test/unit/repeated.ts
@@ -160,6 +160,27 @@ function testRepeatedEnum(root: protobuf.Root) {
   });
 }
 
+function testRepeatedBytes(root: protobuf.Root) {
+  const MessageWithRepeated = root.lookupType('test.MessageWithRepeated');
+  const message = MessageWithRepeated.fromObject({
+    repeatedBytes: ['dmFsdWUgMQo=', 'dmFsdWUgMgo='],
+  });
+  const json = {
+    repeatedBytes: ['dmFsdWUgMQo=', 'dmFsdWUgMgo='],
+  };
+
+  it('serializes to proto3 JSON', () => {
+    const serialized = toProto3JSON(message);
+    assert.deepStrictEqual(serialized, json);
+  });
+
+  it('deserializes from proto3 JSON', () => {
+    const deserialized = fromProto3JSON(MessageWithRepeated, json);
+    assert.deepStrictEqual(deserialized, message);
+  });
+}
+
 testTwoTypesOfLoad('repeated fields', testRepeated);
 testTwoTypesOfLoad('empty repeated fields', testEmptyRepeated);
 testTwoTypesOfLoad('repeated enums', testRepeatedEnum);
+testTwoTypesOfLoad('repeated bytes', testRepeatedBytes);