From f9efbcd5d6798229455584843e1817ef44cb4ab0 Mon Sep 17 00:00:00 2001
From: Joshua Haberman <jhaberman@gmail.com>
Date: Fri, 13 Dec 2019 23:28:25 -0800
Subject: [PATCH] Added missing append fallback.

---
 tests/test_generated_code.c | 20 ++++++++++++++++++++
 upb/msg.c                   | 31 +++++++++++++++++++++++++++----
 2 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/tests/test_generated_code.c b/tests/test_generated_code.c
index 9d8be79ef2..3d1f518b4c 100644
--- a/tests/test_generated_code.c
+++ b/tests/test_generated_code.c
@@ -301,9 +301,29 @@ static void test_int32_map() {
   upb_arena_free(arena);
 }
 
+void test_repeated() {
+  upb_arena *arena = upb_arena_new();
+  protobuf_test_messages_proto3_TestAllTypesProto3 *msg =
+      protobuf_test_messages_proto3_TestAllTypesProto3_new(arena);
+  size_t size;
+  const int *elems;
+
+  protobuf_test_messages_proto3_TestAllTypesProto3_add_repeated_int32(
+      msg, 5, arena);
+
+  elems = protobuf_test_messages_proto3_TestAllTypesProto3_repeated_int32(
+      msg, &size);
+
+  ASSERT(size == 1);
+  ASSERT(elems[0] == 5);
+
+  upb_arena_free(arena);
+}
+
 int run_tests(int argc, char *argv[]) {
   test_scalars();
   test_string_map();
   test_int32_map();
+  test_repeated();
   return 0;
 }
diff --git a/upb/msg.c b/upb/msg.c
index 756c6b5cac..db4de0983a 100644
--- a/upb/msg.c
+++ b/upb/msg.c
@@ -137,21 +137,44 @@ bool _upb_array_realloc(upb_array *arr, size_t min_size, upb_arena *arena) {
   return true;
 }
 
-void *_upb_array_resize_fallback(upb_array **arr_ptr, size_t size,
-                                 upb_fieldtype_t type, upb_arena *arena) {
+static upb_array *getorcreate_array(upb_array **arr_ptr, upb_fieldtype_t type,
+                                    upb_arena *arena) {
   upb_array *arr = *arr_ptr;
   if (!arr) {
     arr = _upb_array_new(arena, type);
     if (!arr) return NULL;
     *arr_ptr = arr;
   }
+  return arr;
+}
 
+static bool resize_array(upb_array *arr, size_t size, upb_arena *arena) {
   if (size > arr->size && !_upb_array_realloc(arr, size, arena)) {
-    return NULL;
+    return false;
   }
 
   arr->len = size;
-  return _upb_array_ptr(arr);
+  return true;
+}
+
+void *_upb_array_resize_fallback(upb_array **arr_ptr, size_t size,
+                                 upb_fieldtype_t type, upb_arena *arena) {
+  upb_array *arr = getorcreate_array(arr_ptr, type, arena);
+  return arr && resize_array(arr, size, arena) ? _upb_array_ptr(arr) : NULL;
+}
+
+bool _upb_array_append_fallback(upb_array **arr_ptr, const void *value,
+                                upb_fieldtype_t type, upb_arena *arena) {
+  upb_array *arr = getorcreate_array(arr_ptr, type, arena);
+  size_t elem = arr->len;
+  int lg2 = _upb_fieldtype_to_sizelg2[type];
+  char *data;
+
+  if (!arr || !resize_array(arr, elem + 1, arena)) return false;
+
+  data = _upb_array_ptr(arr);
+  memcpy(data + (elem << lg2), value, 1 << lg2);
+  return true;
 }
 
 /** upb_map *******************************************************************/