Added C++ test for the bug.

tests/test.proto

@@ -11,3 +11,38 @@ message MessageName {
   optional int32 field1 = 1;
   optional int32 field2 = 2;
 }
+
+message HelloRequest {
+  optional uint32 id = 1;
+  optional uint32 random_name_a0 = 2;
+  optional uint32 random_name_a1 = 3;
+  optional uint32 random_name_a2 = 4;
+  optional uint32 random_name_a3 = 5;
+  optional uint32 random_name_a4 = 6;
+  optional uint32 random_name_a5 = 7;
+  optional uint32 random_name_a6 = 8;
+  optional uint32 random_name_a7 = 9;
+  optional uint32 random_name_a8 = 10;
+  optional uint32 random_name_a9 = 11;
+  optional uint32 random_name_b0 = 12;
+  optional uint32 random_name_b1 = 13;
+  optional uint32 random_name_b2 = 14;
+  optional uint32 random_name_b3 = 15;
+  optional uint32 random_name_b4 = 16;
+  optional uint32 random_name_b5 = 17;
+  optional uint32 random_name_b6 = 18;
+  optional uint32 random_name_b7 = 19;
+  optional uint32 random_name_b8 = 20;
+  optional uint32 random_name_b9 = 21;
+  optional uint32 random_name_c0 = 22;
+  optional uint32 random_name_c1 = 23;
+  optional uint32 random_name_c2 = 24;
+  optional uint32 random_name_c3 = 25;
+  optional uint32 random_name_c4 = 26;
+  optional uint32 random_name_c5 = 27;
+  optional uint32 random_name_c6 = 28;
+  optional uint32 random_name_c7 = 29;
+  optional uint32 random_name_c8 = 30;
+  optional uint32 random_name_c9 = 31;
+  optional string version = 32;
+}

tests/test_generated_code.cc

@@ -30,9 +30,10 @@
  * upb/def.c and tests/conformance_upb.c, respectively).
  */
 
+#include "gtest/gtest.h"
 #include "src/google/protobuf/test_messages_proto3.upb.h"
 #include "tests/test.upb.h"
-#include "gtest/gtest.h"
+#include "upb/upb.hpp"
 
 #define MIN(x, y) ((x) < (y) ? (x) : (y))
 
@@ -411,6 +412,16 @@ TEST(GeneratedCode, TestRepeated) {
   upb_Arena_Free(arena);
 }
 
+TEST(GeneratedCode, Issue9440) {
+  upb::Arena arena;
+  upb_test_HelloRequest* msg = upb_test_HelloRequest_new(arena.ptr());
+  upb_test_HelloRequest_set_id(msg, 8);
+  EXPECT_EQ(8, upb_test_HelloRequest_id(msg));
+  char str[] = "1";
+  upb_test_HelloRequest_set_version(msg, upb_StringView{str, strlen(str)});
+  EXPECT_EQ(8, upb_test_HelloRequest_id(msg));
+}
+
 TEST(GeneratedCode, NullDecodeBuffer) {
   upb_Arena* arena = upb_Arena_New();
   protobuf_test_messages_proto3_TestAllTypesProto3* msg =