Update callers to use noncontiguous APIs PiperOrigin-RevId: 696922501

diff --git a/csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs b/csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs
deleted file mode 100644
index 208ce1f..0000000
--- a/csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs
+++ /dev/null

@@ -1,17 +0,0 @@
-#region Copyright notice and license
-// Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
-#endregion
-
-namespace Google.Protobuf.Reflection;
-
-internal sealed partial class FeatureSetDescriptor
-{
-    // Canonical serialized form of the edition defaults, generated by embed_edition_defaults.
-    private const string DefaultsBase64 =
-        "ChMYhAciACoMCAEQAhgCIAMoATACChMY5wciACoMCAIQARgBIAIoATABChMY6AciDAgBEAEYASACKAEwASoAIOYHKOgH";
-}

diff --git a/upb/message/copy.c b/upb/message/copy.c
index 94f4105..e9c5f61 100644
--- a/upb/message/copy.c
+++ b/upb/message/copy.c

@@ -8,6 +8,7 @@
 #include "upb/message/copy.h"
 
 #include <stdbool.h>
+#include <stdint.h>
 #include <string.h>
 
 #include "upb/base/descriptor_constants.h"
@@ -280,12 +281,12 @@
   }
 
   // Clone unknowns.
-  size_t unknown_size = 0;
-  const char* ptr = upb_Message_GetUnknown(src, &unknown_size);
-  if (unknown_size != 0) {
-    UPB_ASSERT(ptr);
+  uintptr_t iter = kUpb_Message_UnknownBegin;
+  upb_StringView unknowns;
+  while (upb_Message_NextUnknown(src, &unknowns, &iter)) {
     // Make a copy into destination arena.
-    if (!UPB_PRIVATE(_upb_Message_AddUnknown)(dst, ptr, unknown_size, arena)) {
+    if (!UPB_PRIVATE(_upb_Message_AddUnknown)(dst, unknowns.data, unknowns.size,
+                                              arena)) {
       return NULL;
     }
   }

diff --git a/upb/message/test.cc b/upb/message/test.cc
index 446da19..a96a778 100644
--- a/upb/message/test.cc
+++ b/upb/message/test.cc

@@ -501,6 +501,7 @@
   // parse into second instance
   upb_test_TestMapFieldExtra* test_msg_extra2 =
       upb_test_TestMapFieldExtra_parse(serialized, size, arena.ptr());
+  ASSERT_NE(nullptr, test_msg_extra2);
   ASSERT_TRUE(
       upb_test_TestMapFieldExtra_map_field_get(test_msg_extra2, 0, nullptr));
 }

diff --git a/upb/wire/decode.c b/upb/wire/decode.c
index a3e3612..e195d9f 100644
--- a/upb/wire/decode.c
+++ b/upb/wire/decode.c

@@ -288,11 +288,14 @@
   upb_Message* existing =
       UPB_PRIVATE(_upb_TaggedMessagePtr_GetEmptyMessage)(tagged);
   upb_Message* promoted = _upb_Decoder_NewSubMessage(d, subs, field, target);
-  size_t size;
-  const char* unknown = upb_Message_GetUnknown(existing, &size);
-  upb_DecodeStatus status = upb_Decode(unknown, size, promoted, subl, d->extreg,
-                                       d->options, &d->arena);
-  if (status != kUpb_DecodeStatus_Ok) _upb_Decoder_ErrorJmp(d, status);
+  uintptr_t iter = kUpb_Message_UnknownBegin;
+  upb_StringView unknown;
+  while (upb_Message_NextUnknown(existing, &unknown, &iter)) {
+    upb_DecodeStatus status =
+        upb_Decode(unknown.data, unknown.size, promoted, subl, d->extreg,
+                   d->options, &d->arena);
+    if (status != kUpb_DecodeStatus_Ok) _upb_Decoder_ErrorJmp(d, status);
+  }
   return promoted;
 }
 
@@ -658,10 +661,7 @@
 
   ptr = _upb_Decoder_DecodeSubMessage(d, ptr, &ent.message, subs, field,
                                       val->size);
-  // check if ent had any unknown fields
-  size_t size;
-  upb_Message_GetUnknown(&ent.message, &size);
-  if (size != 0) {
+  if (upb_Message_HasUnknown(&ent.message)) {
     char* buf;
     size_t size;
     uint32_t tag =

diff --git a/upb/wire/encode.c b/upb/wire/encode.c
index 5764199..85764e3 100644
--- a/upb/wire/encode.c
+++ b/upb/wire/encode.c

@@ -565,11 +565,22 @@
   }
 
   if ((e->options & kUpb_EncodeOption_SkipUnknown) == 0) {
-    size_t unknown_size;
-    const char* unknown = upb_Message_GetUnknown(msg, &unknown_size);
-
-    if (unknown) {
-      encode_bytes(e, unknown, unknown_size);
+    size_t unknown_size = 0;
+    uintptr_t iter = kUpb_Message_UnknownBegin;
+    upb_StringView unknown;
+    // Need to write in reverse order, but list is single-linked; scan to
+    // reserve capacity up front, then write in-order
+    while (upb_Message_NextUnknown(msg, &unknown, &iter)) {
+      unknown_size += unknown.size;
+    }
+    if (unknown_size != 0) {
+      encode_reserve(e, unknown_size);
+      char* ptr = e->ptr;
+      iter = kUpb_Message_UnknownBegin;
+      while (upb_Message_NextUnknown(msg, &unknown, &iter)) {
+        memcpy(ptr, unknown.data, unknown.size);
+        ptr += unknown.size;
+      }
     }
   }