diff --git a/java/core/src/main/java/com/google/protobuf/ByteString.java b/java/core/src/main/java/com/google/protobuf/ByteString.java
index 3cf98162fe..0e03ebd14e 100644
--- a/java/core/src/main/java/com/google/protobuf/ByteString.java
+++ b/java/core/src/main/java/com/google/protobuf/ByteString.java
@@ -1143,7 +1143,7 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
       synchronized (this) {
         // Copy the information we need into local variables so as to hold
         // the lock for as short a time as possible.
-        cachedFlushBuffers = flushedBuffers.toArray(new ByteString[flushedBuffers.size()]);
+        cachedFlushBuffers = flushedBuffers.toArray(new ByteString[0]);
         cachedBuffer = buffer;
         cachedBufferPos = bufferPos;
       }
diff --git a/src/Makefile.am b/src/Makefile.am
index 42975d11e2..e10ed063d5 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -177,6 +177,7 @@ nobase_include_HEADERS =                                         \
   google/protobuf/util/field_comparator.h                        \
   google/protobuf/util/field_mask_util.h                         \
   google/protobuf/util/json_util.h                               \
+  google/protobuf/util/zero_copy_sink.h                          \
   google/protobuf/util/message_differencer.h                     \
   google/protobuf/util/time_util.h                               \
   google/protobuf/util/type_resolver.h                           \
@@ -311,6 +312,7 @@ libprotobuf_la_SOURCES =                                       \
   google/protobuf/util/internal/utility.cc                     \
   google/protobuf/util/internal/utility.h                      \
   google/protobuf/util/json_util.cc                            \
+  google/protobuf/util/zero_copy_sink.cc                       \
   google/protobuf/util/message_differencer.cc                  \
   google/protobuf/util/time_util.cc                            \
   google/protobuf/util/type_resolver_util.cc                   \
@@ -829,6 +831,7 @@ protobuf_test_SOURCES =                                        \
   google/protobuf/util/internal/protostream_objectwriter_test.cc \
   google/protobuf/util/internal/type_info_test_helper.cc       \
   google/protobuf/util/json_util_test.cc                       \
+  google/protobuf/util/zero_copy_sink_test.cc                  \
   google/protobuf/util/message_differencer_unittest.cc         \
   google/protobuf/util/time_util_test.cc                       \
   google/protobuf/util/type_resolver_util_test.cc              \
diff --git a/src/file_lists.cmake b/src/file_lists.cmake
index c849a6236e..32f10b2705 100644
--- a/src/file_lists.cmake
+++ b/src/file_lists.cmake
@@ -92,6 +92,7 @@ set(libprotobuf_srcs
   ${protobuf_SOURCE_DIR}/src/google/protobuf/util/message_differencer.cc
   ${protobuf_SOURCE_DIR}/src/google/protobuf/util/time_util.cc
   ${protobuf_SOURCE_DIR}/src/google/protobuf/util/type_resolver_util.cc
+  ${protobuf_SOURCE_DIR}/src/google/protobuf/util/zero_copy_sink.cc
   ${protobuf_SOURCE_DIR}/src/google/protobuf/wire_format.cc
   ${protobuf_SOURCE_DIR}/src/google/protobuf/wire_format_lite.cc
   ${protobuf_SOURCE_DIR}/src/google/protobuf/wrappers.pb.cc
@@ -213,6 +214,7 @@ set(libprotobuf_hdrs
   ${protobuf_SOURCE_DIR}/src/google/protobuf/util/time_util.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/util/type_resolver.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/util/type_resolver_util.h
+  ${protobuf_SOURCE_DIR}/src/google/protobuf/util/zero_copy_sink.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/wire_format.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/wire_format_lite.h
   ${protobuf_SOURCE_DIR}/src/google/protobuf/wrappers.pb.h
@@ -843,6 +845,7 @@ set(util_test_files
   ${protobuf_SOURCE_DIR}/src/google/protobuf/util/message_differencer_unittest.cc
   ${protobuf_SOURCE_DIR}/src/google/protobuf/util/time_util_test.cc
   ${protobuf_SOURCE_DIR}/src/google/protobuf/util/type_resolver_util_test.cc
+  ${protobuf_SOURCE_DIR}/src/google/protobuf/util/zero_copy_sink_test.cc
 )
 
 # //src/google/protobuf/util:test_proto_srcs
diff --git a/src/google/protobuf/arena.cc b/src/google/protobuf/arena.cc
index 6ba508a5f0..38ea055310 100644
--- a/src/google/protobuf/arena.cc
+++ b/src/google/protobuf/arena.cc
@@ -134,14 +134,6 @@ SerialArena::Memory SerialArena::Free(Deallocator deallocator) {
   return mem;
 }
 
-PROTOBUF_NOINLINE
-std::pair<void*, SerialArena::CleanupNode*>
-SerialArena::AllocateAlignedWithCleanupFallback(
-    size_t n, const AllocationPolicy* policy) {
-  AllocateNewBlock(n + kCleanupSize, policy);
-  return AllocateFromExistingWithCleanupFallback(n);
-}
-
 PROTOBUF_NOINLINE
 void* SerialArena::AllocateAlignedFallback(size_t n,
                                            const AllocationPolicy* policy) {
@@ -408,15 +400,16 @@ uint64_t ThreadSafeArena::Reset() {
   return space_allocated;
 }
 
-std::pair<void*, SerialArena::CleanupNode*>
-ThreadSafeArena::AllocateAlignedWithCleanup(size_t n,
-                                            const std::type_info* type) {
+void* ThreadSafeArena::AllocateAlignedWithCleanup(size_t n, size_t align,
+                                                  void (*destructor)(void*),
+                                                  const std::type_info* type) {
   SerialArena* arena;
   if (PROTOBUF_PREDICT_TRUE(!alloc_policy_.should_record_allocs() &&
                             GetSerialArenaFast(&arena))) {
-    return arena->AllocateAlignedWithCleanup(n, alloc_policy_.get());
+    return arena->AllocateAlignedWithCleanup(n, align, destructor,
+                                             alloc_policy_.get());
   } else {
-    return AllocateAlignedWithCleanupFallback(n, type);
+    return AllocateAlignedWithCleanupFallback(n, align, destructor, type);
   }
 }
 
@@ -443,18 +436,19 @@ void* ThreadSafeArena::AllocateAlignedFallback(size_t n,
 }
 
 PROTOBUF_NOINLINE
-std::pair<void*, SerialArena::CleanupNode*>
-ThreadSafeArena::AllocateAlignedWithCleanupFallback(
-    size_t n, const std::type_info* type) {
+void* ThreadSafeArena::AllocateAlignedWithCleanupFallback(
+    size_t n, size_t align, void (*destructor)(void*),
+    const std::type_info* type) {
   if (alloc_policy_.should_record_allocs()) {
-    alloc_policy_.RecordAlloc(type, n);
+    alloc_policy_.RecordAlloc(type, internal::AlignUpTo(n, align));
     SerialArena* arena;
     if (GetSerialArenaFast(&arena)) {
-      return arena->AllocateAlignedWithCleanup(n, alloc_policy_.get());
+      return arena->AllocateAlignedWithCleanup(n, align, destructor,
+                                               alloc_policy_.get());
     }
   }
   return GetSerialArenaFallback(&thread_cache())
-      ->AllocateAlignedWithCleanup(n, alloc_policy_.get());
+      ->AllocateAlignedWithCleanup(n, align, destructor, alloc_policy_.get());
 }
 
 uint64_t ThreadSafeArena::SpaceAllocated() const {
@@ -526,9 +520,10 @@ void* Arena::AllocateAlignedWithHookForArray(size_t n,
 }
 
 PROTOBUF_FUNC_ALIGN(32)
-std::pair<void*, internal::SerialArena::CleanupNode*>
-Arena::AllocateAlignedWithCleanup(size_t n, const std::type_info* type) {
-  return impl_.AllocateAlignedWithCleanup(n, type);
+void* Arena::AllocateAlignedWithCleanup(size_t n, size_t align,
+                                        void (*destructor)(void*),
+                                        const std::type_info* type) {
+  return impl_.AllocateAlignedWithCleanup(n, align, destructor, type);
 }
 
 }  // namespace protobuf
diff --git a/src/google/protobuf/arena.h b/src/google/protobuf/arena.h
index 0f9f81366f..ee4b4db607 100644
--- a/src/google/protobuf/arena.h
+++ b/src/google/protobuf/arena.h
@@ -90,12 +90,6 @@ class RepeatedPtrFieldBase;  // defined in repeated_ptr_field.h
 template <typename Type>
 class GenericTypeHandler;  // defined in repeated_field.h
 
-inline PROTOBUF_ALWAYS_INLINE
-void* AlignTo(void* ptr, size_t align) {
-  return reinterpret_cast<void*>(
-      (reinterpret_cast<uintptr_t>(ptr) + align - 1) & (~align + 1));
-}
-
 // Templated cleanup methods.
 template <typename T>
 void arena_destruct_object(void* object) {
@@ -420,7 +414,18 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   template <typename T>
   class InternalHelper {
    private:
-    struct Rank1 {};
+    // A SFINAE friendly trait that probes for `U` but always evalues to
+    // `Arena*`.
+    template <typename U>
+    using EnableIfArena =
+        typename std::enable_if<std::is_same<Arena*, U>::value, Arena*>::type;
+
+    // Rather than use SFINAE that must fully cover the space of options in a
+    // mutually exclusive fashion, we use implicit conversions to base classes
+    // to force an explicit ranking for our preferences.  The lowest ranked
+    // version that compiles will be accepted.
+    struct Rank2 {};
+    struct Rank1 : Rank2 {};
     struct Rank0 : Rank1 {};
 
     static Arena* GetOwningArena(const T* p) {
@@ -429,7 +434,7 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
 
     template <typename U>
     static auto GetOwningArena(Rank0, const U* p)
-        -> decltype(p->GetOwningArena()) {
+        -> EnableIfArena<decltype(p->GetOwningArena())> {
       return p->GetOwningArena();
     }
 
@@ -440,35 +445,31 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
 
     static void InternalSwap(T* a, T* b) { a->InternalSwap(b); }
 
-    static Arena* GetArenaForAllocationInternal(
-        const T* p, std::true_type /*is_derived_from<MessageLite>*/) {
-      return p->GetArenaForAllocation();
+    static Arena* GetArenaForAllocation(const T* p) {
+      return GetArenaForAllocation(Rank0{}, p);
     }
 
-    static Arena* GetArenaForAllocationInternal(
-        const T* p, std::false_type /*is_derived_from<MessageLite>*/) {
-      return GetArenaForAllocationForNonMessage(
-          p, typename is_arena_constructable::type());
+    static Arena* GetArena(const T* p) {
+      // Rather than replicate probing for `GetArena` with fallback to nullptr,
+      // we borrow the implementation of `GetArenaForAllocation` but skip
+      // `Rank0` which probes for `GetArenaForAllocation`.
+      return GetArenaForAllocation(Rank1{}, p);
     }
 
-    static Arena* GetArenaForAllocationForNonMessage(
-        const T* p, std::true_type /*is_arena_constructible*/) {
-      return p->GetArena();
-    }
-
-    static Arena* GetArenaForAllocationForNonMessage(
-        const T* p, std::false_type /*is_arena_constructible*/) {
-      return GetArenaForAllocationForNonMessageNonArenaConstructible(
-          p, typename has_get_arena::type());
+    template <typename U>
+    static auto GetArenaForAllocation(Rank0, const U* p)
+        -> EnableIfArena<decltype(p->GetArenaForAllocation())> {
+      return p->GetArenaForAllocation();
     }
 
-    static Arena* GetArenaForAllocationForNonMessageNonArenaConstructible(
-        const T* p, std::true_type /*has_get_arena*/) {
+    template <typename U>
+    static auto GetArenaForAllocation(Rank1, const U* p)
+        -> EnableIfArena<decltype(p->GetArena())> {
       return p->GetArena();
     }
 
-    static Arena* GetArenaForAllocationForNonMessageNonArenaConstructible(
-        const T* /* p */, std::false_type /*has_get_arena*/) {
+    template <typename U>
+    static Arena* GetArenaForAllocation(Rank2, const U* p) {
       return nullptr;
     }
 
@@ -494,18 +495,6 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
                                              sizeof(char)>
         is_arena_constructable;
 
-    template <typename U,
-              typename std::enable_if<
-                  std::is_same<Arena*, decltype(std::declval<const U>()
-                                                    .GetArena())>::value,
-                  int>::type = 0>
-    static char HasGetArena(decltype(&U::GetArena));
-    template <typename U>
-    static double HasGetArena(...);
-
-    typedef std::integral_constant<bool, sizeof(HasGetArena<T>(nullptr)) ==
-                                             sizeof(char)>
-        has_get_arena;
 
     template <typename... Args>
     static T* Construct(void* ptr, Args&&... args) {
@@ -516,8 +505,6 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
       return new T(nullptr);
     }
 
-    static Arena* GetArena(const T* p) { return p->GetArena(); }
-
     friend class Arena;
     friend class TestUtil::ReflectionTester;
   };
@@ -533,8 +520,7 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   // For internal use only.
   template <typename T>
   static Arena* InternalGetArenaForAllocation(const T* p) {
-    return InternalHelper<T>::GetArenaForAllocationInternal(
-        p, std::is_convertible<T*, MessageLite*>());
+    return InternalHelper<T>::GetArenaForAllocation(p);
   }
 
   // Creates message-owned arena.  For internal use only.
@@ -566,9 +552,6 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
  private:
   internal::ThreadSafeArena impl_;
 
-  template <typename T>
-  struct has_get_arena : InternalHelper<T>::has_get_arena {};
-
   // Constructor solely used by message-owned arena.
   inline Arena(internal::MessageOwned) : impl_(internal::MessageOwned{}) {}
 
@@ -620,18 +603,7 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
     if (destructor == nullptr) {
       return AllocateAlignedWithHook(size, align, type);
     } else {
-      if (align <= 8) {
-        auto res = AllocateAlignedWithCleanup(internal::AlignUpTo8(size), type);
-        res.second->elem = res.first;
-        res.second->cleanup = destructor;
-        return res.first;
-      } else {
-        auto res = AllocateAlignedWithCleanup(size + align - 8, type);
-        auto ptr = internal::AlignTo(res.first, align);
-        res.second->elem = ptr;
-        res.second->cleanup = destructor;
-        return ptr;
-      }
+      return AllocateAlignedWithCleanup(size, align, destructor, type);
     }
   }
 
@@ -774,26 +746,10 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   // Implementation for GetArena(). Only message objects with
   // InternalArenaConstructable_ tags can be associated with an arena, and such
   // objects must implement a GetArena() method.
-  template <typename T, typename std::enable_if<
-                            is_arena_constructable<T>::value, int>::type = 0>
+  template <typename T>
   PROTOBUF_ALWAYS_INLINE static Arena* GetArenaInternal(const T* value) {
     return InternalHelper<T>::GetArena(value);
   }
-  template <typename T,
-            typename std::enable_if<!is_arena_constructable<T>::value &&
-                                        has_get_arena<T>::value,
-                                    int>::type = 0>
-  PROTOBUF_ALWAYS_INLINE static Arena* GetArenaInternal(const T* value) {
-    return value->GetArena();
-  }
-  template <typename T,
-            typename std::enable_if<!is_arena_constructable<T>::value &&
-                                        !has_get_arena<T>::value,
-                                    int>::type = 0>
-  PROTOBUF_ALWAYS_INLINE static Arena* GetArenaInternal(const T* value) {
-    (void)value;
-    return nullptr;
-  }
 
   void* AllocateAlignedWithHookForArray(size_t n, size_t align,
                                         const std::type_info* type) {
@@ -828,8 +784,9 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   void* AllocateAlignedNoHook(size_t n);
   void* AllocateAlignedWithHook(size_t n, const std::type_info* type);
   void* AllocateAlignedWithHookForArray(size_t n, const std::type_info* type);
-  std::pair<void*, internal::SerialArena::CleanupNode*>
-  AllocateAlignedWithCleanup(size_t n, const std::type_info* type);
+  void* AllocateAlignedWithCleanup(size_t n, size_t align,
+                                   void (*destructor)(void*),
+                                   const std::type_info* type);
 
   template <typename Type>
   friend class internal::GenericTypeHandler;
diff --git a/src/google/protobuf/arena_impl.h b/src/google/protobuf/arena_impl.h
index 76727688b5..0bfceb413a 100644
--- a/src/google/protobuf/arena_impl.h
+++ b/src/google/protobuf/arena_impl.h
@@ -67,6 +67,24 @@ inline constexpr size_t AlignUpTo8(size_t n) {
   return (n + 7) & static_cast<size_t>(-8);
 }
 
+inline constexpr size_t AlignUpTo(size_t n, size_t a) {
+  // We are wasting space by over allocating align - 8 bytes. Compared to a
+  // dedicated function that takes current alignment in consideration.  Such a
+  // scheme would only waste (align - 8)/2 bytes on average, but requires a
+  // dedicated function in the outline arena allocation functions. Possibly
+  // re-evaluate tradeoffs later.
+  return a <= 8 ? AlignUpTo8(n) : n + a - 8;
+}
+
+inline PROTOBUF_ALWAYS_INLINE void* AlignTo(void* p, size_t a) {
+  if (a <= 8) {
+    return p;
+  } else {
+    auto u = reinterpret_cast<uintptr_t>(p);
+    return reinterpret_cast<void*>((u + a - 1) & (~a + 1));
+  }
+}
+
 using LifecycleIdAtomic = uint64_t;
 
 // MetricsCollector collects stats for a particular arena.
@@ -198,16 +216,10 @@ enum class AllocationClient { kDefault, kArray };
 // This class manages
 // 1) Arena bump allocation + owning memory blocks.
 // 2) Maintaining a cleanup list.
-// It delagetes the actual memory allocation back to ThreadSafeArena, which
+// It delegates the actual memory allocation back to ThreadSafeArena, which
 // contains the information on block growth policy and backing memory allocation
 // used.
 class PROTOBUF_EXPORT SerialArena {
- public:
-  struct Memory {
-    void* ptr;
-    size_t size;
-  };
-
   // Node contains the ptr of the object to be cleaned up and the associated
   // cleanup function ptr.
   struct CleanupNode {
@@ -215,6 +227,12 @@ class PROTOBUF_EXPORT SerialArena {
     void (*cleanup)(void*);  // Function pointer to the destructor or deleter.
   };
 
+ public:
+  struct Memory {
+    void* ptr;
+    size_t size;
+  };
+
   void CleanupList();
   uint64_t SpaceAllocated() const {
     return space_allocated_.load(std::memory_order_relaxed);
@@ -270,11 +288,11 @@ class PROTOBUF_EXPORT SerialArena {
 
  private:
   void* AllocateFromExisting(size_t n) {
-    void* ret = ptr_;
-    ptr_ += n;
 #ifdef ADDRESS_SANITIZER
-    ASAN_UNPOISON_MEMORY_REGION(ret, n);
+    ASAN_UNPOISON_MEMORY_REGION(ptr_, n);
 #endif  // ADDRESS_SANITIZER
+    void* ret = ptr_;
+    ptr_ += n;
     return ret;
   }
 
@@ -332,36 +350,48 @@ class PROTOBUF_EXPORT SerialArena {
     return true;
   }
 
-  std::pair<void*, CleanupNode*> AllocateAlignedWithCleanup(
-      size_t n, const AllocationPolicy* policy) {
-    GOOGLE_DCHECK_EQ(internal::AlignUpTo8(n), n);  // Must be already aligned.
-    if (PROTOBUF_PREDICT_FALSE(!HasSpace(n + kCleanupSize))) {
-      return AllocateAlignedWithCleanupFallback(n, policy);
+  void* AllocateAlignedWithCleanup(size_t n, size_t align,
+                                   void (*destructor)(void*),
+                                   const AllocationPolicy* policy) {
+    size_t required = AlignUpTo(n, align) + kCleanupSize;
+    if (PROTOBUF_PREDICT_FALSE(!HasSpace(required))) {
+      AllocateNewBlock(required, policy);
     }
-    return AllocateFromExistingWithCleanupFallback(n);
+    return AllocateFromExistingWithCleanupFallback(n, align, destructor);
+  }
+
+  void AddCleanup(void* elem, void (*cleanup)(void*),
+                  const AllocationPolicy* policy) {
+    if (PROTOBUF_PREDICT_FALSE(!HasSpace(kCleanupSize))) {
+      AllocateNewBlock(kCleanupSize, policy);
+    }
+    AddCleanupFromExisting(elem, cleanup);
   }
 
  private:
-  std::pair<void*, CleanupNode*> AllocateFromExistingWithCleanupFallback(
-      size_t n) {
-    void* ret = ptr_;
-    ptr_ += n;
-    limit_ -= kCleanupSize;
+  void* AllocateFromExistingWithCleanupFallback(size_t n, size_t align,
+                                                void (*destructor)(void*)) {
+    n = AlignUpTo(n, align);
 #ifdef ADDRESS_SANITIZER
-    ASAN_UNPOISON_MEMORY_REGION(ret, n);
-    ASAN_UNPOISON_MEMORY_REGION(limit_, kCleanupSize);
+    ASAN_UNPOISON_MEMORY_REGION(ptr_, n);
 #endif  // ADDRESS_SANITIZER
-    return CreatePair(ret, reinterpret_cast<CleanupNode*>(limit_));
+    void* ret = internal::AlignTo(ptr_, align);
+    ptr_ += n;
+    AddCleanupFromExisting(ret, destructor);
+    return ret;
   }
 
- public:
-  void AddCleanup(void* elem, void (*cleanup)(void*),
-                  const AllocationPolicy* policy) {
-    auto res = AllocateAlignedWithCleanup(0, policy);
-    res.second->elem = elem;
-    res.second->cleanup = cleanup;
+  void AddCleanupFromExisting(void* elem, void (*cleanup)(void*)) {
+#ifdef ADDRESS_SANITIZER
+    ASAN_UNPOISON_MEMORY_REGION(limit_ - kCleanupSize, kCleanupSize);
+#endif  // ADDRESS_SANITIZER
+    limit_ -= kCleanupSize;
+    auto c = reinterpret_cast<CleanupNode*>(limit_);
+    c->elem = elem;
+    c->cleanup = cleanup;
   }
 
+ public:
   void* owner() const { return owner_; }
   SerialArena* next() const { return next_; }
   void set_next(SerialArena* next) { next_ = next; }
@@ -427,14 +457,8 @@ class PROTOBUF_EXPORT SerialArena {
   // Constructor is private as only New() should be used.
   inline SerialArena(Block* b, void* owner, ThreadSafeArenaStats* stats);
   void* AllocateAlignedFallback(size_t n, const AllocationPolicy* policy);
-  std::pair<void*, CleanupNode*> AllocateAlignedWithCleanupFallback(
-      size_t n, const AllocationPolicy* policy);
   void AllocateNewBlock(size_t n, const AllocationPolicy* policy);
 
-  std::pair<void*, CleanupNode*> CreatePair(void* ptr, CleanupNode* node) {
-    return {ptr, node};
-  }
-
  public:
   static constexpr size_t kBlockHeaderSize = AlignUpTo8(sizeof(Block));
   static constexpr size_t kCleanupSize = AlignUpTo8(sizeof(CleanupNode));
@@ -469,6 +493,13 @@ class PROTOBUF_EXPORT ThreadSafeArena {
     InitializeWithPolicy(mem, size, policy);
   }
 
+  // All protos have pointers back to the arena hence Arena must have
+  // pointer stability.
+  ThreadSafeArena(const ThreadSafeArena&) = delete;
+  ThreadSafeArena& operator=(const ThreadSafeArena&) = delete;
+  ThreadSafeArena(ThreadSafeArena&&) = delete;
+  ThreadSafeArena& operator=(ThreadSafeArena&&) = delete;
+
   // Destructor deletes all owned heap allocated objects, and destructs objects
   // that have non-trivial destructors, except for proto2 message objects whose
   // destructors can be skipped. Also, frees all blocks except the initial block
@@ -512,8 +543,9 @@ class PROTOBUF_EXPORT ThreadSafeArena {
     return false;
   }
 
-  std::pair<void*, SerialArena::CleanupNode*> AllocateAlignedWithCleanup(
-      size_t n, const std::type_info* type);
+  void* AllocateAlignedWithCleanup(size_t n, size_t align,
+                                   void (*destructor)(void*),
+                                   const std::type_info* type);
 
   // Add object pointer and cleanup function pointer to the list.
   void AddCleanup(void* elem, void (*cleanup)(void*));
@@ -541,8 +573,9 @@ class PROTOBUF_EXPORT ThreadSafeArena {
   void InitializeFrom(void* mem, size_t size);
   void InitializeWithPolicy(void* mem, size_t size, AllocationPolicy policy);
   void* AllocateAlignedFallback(size_t n, const std::type_info* type);
-  std::pair<void*, SerialArena::CleanupNode*>
-  AllocateAlignedWithCleanupFallback(size_t n, const std::type_info* type);
+  void* AllocateAlignedWithCleanupFallback(size_t n, size_t align,
+                                           void (*destructor)(void*),
+                                           const std::type_info* type);
 
   void Init();
   void SetInitialBlock(void* mem, size_t size);
@@ -659,12 +692,6 @@ class PROTOBUF_EXPORT ThreadSafeArena {
 
   ThreadSafeArenaStatsHandle arena_stats_;
 
-  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ThreadSafeArena);
-  // All protos have pointers back to the arena hence Arena must have
-  // pointer stability.
-  ThreadSafeArena(ThreadSafeArena&&) = delete;
-  ThreadSafeArena& operator=(ThreadSafeArena&&) = delete;
-
  public:
   // kBlockHeaderSize is sizeof(Block), aligned up to the nearest multiple of 8
   // to protect the invariant that pos is always at a multiple of 8.
diff --git a/src/google/protobuf/arenastring.cc b/src/google/protobuf/arenastring.cc
index 65da0d3d4d..03b1438b44 100644
--- a/src/google/protobuf/arenastring.cc
+++ b/src/google/protobuf/arenastring.cc
@@ -125,8 +125,7 @@ void ArenaStringPtr::Set(ConstStringParam value, Arena* arena) {
   } else {
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
     if (arena == nullptr) {
-      GOOGLE_DCHECK(tagged_ptr_.IsAllocated());
-      auto* old = tagged_ptr_.Get();
+      auto* old = tagged_ptr_.GetIfAllocated();
       tagged_ptr_ = CreateString(value);
       delete old;
     } else {
diff --git a/src/google/protobuf/compiler/command_line_interface.cc b/src/google/protobuf/compiler/command_line_interface.cc
index 5e9a2c4185..a688bcfb06 100644
--- a/src/google/protobuf/compiler/command_line_interface.cc
+++ b/src/google/protobuf/compiler/command_line_interface.cc
@@ -1276,6 +1276,7 @@ bool CommandLineInterface::ParseInputFiles(
     }
     parsed_files->push_back(parsed_file);
 
+
     // Enforce --disallow_services.
     if (disallow_services_ && parsed_file->service_count() > 0) {
       std::cerr << parsed_file->name()
diff --git a/src/google/protobuf/compiler/command_line_interface.h b/src/google/protobuf/compiler/command_line_interface.h
index e8425508b1..8064b397f8 100644
--- a/src/google/protobuf/compiler/command_line_interface.h
+++ b/src/google/protobuf/compiler/command_line_interface.h
@@ -398,7 +398,7 @@ class PROTOC_EXPORT CommandLineInterface {
   // True if we should treat warnings as errors that fail the compilation.
   bool fatal_warnings_ = false;
 
-  std::vector<std::pair<std::string, std::string> >
+  std::vector<std::pair<std::string, std::string>>
       proto_path_;                        // Search path for proto files.
   std::vector<std::string> input_files_;  // Names of the input proto files.
 
diff --git a/src/google/protobuf/compiler/parser.cc b/src/google/protobuf/compiler/parser.cc
index 5bd37d147b..f220fad8be 100644
--- a/src/google/protobuf/compiler/parser.cc
+++ b/src/google/protobuf/compiler/parser.cc
@@ -634,14 +634,17 @@ bool Parser::Parse(io::Tokenizer* input, FileDescriptorProto* file) {
     root_location.RecordLegacyLocation(file,
                                        DescriptorPool::ErrorCollector::OTHER);
 
-    if (require_syntax_identifier_ || LookingAt("syntax")) {
+    if (require_syntax_identifier_ || LookingAt("syntax")
+    ) {
       if (!ParseSyntaxIdentifier(root_location)) {
         // Don't attempt to parse the file if we didn't recognize the syntax
         // identifier.
         return false;
       }
       // Store the syntax into the file.
-      if (file != nullptr) file->set_syntax(syntax_identifier_);
+      if (file != nullptr) {
+        file->set_syntax(syntax_identifier_);
+      }
     } else if (!stop_after_syntax_identifier_) {
       GOOGLE_LOG(WARNING) << "No syntax specified for the proto file: " << file->name()
                    << ". Please use 'syntax = \"proto2\";' "
@@ -678,9 +681,10 @@ bool Parser::Parse(io::Tokenizer* input, FileDescriptorProto* file) {
 bool Parser::ParseSyntaxIdentifier(const LocationRecorder& parent) {
   LocationRecorder syntax_location(parent,
                                    FileDescriptorProto::kSyntaxFieldNumber);
-  DO(Consume(
-      "syntax",
-      "File must begin with a syntax statement, e.g. 'syntax = \"proto2\";'."));
+    DO(Consume("syntax",
+               "File must begin with a syntax statement, e.g. 'syntax = "
+               "\"proto2\";'."));
+
   DO(Consume("="));
   io::Tokenizer::Token syntax_token = input_->current();
   std::string syntax;
@@ -688,7 +692,6 @@ bool Parser::ParseSyntaxIdentifier(const LocationRecorder& parent) {
   DO(ConsumeEndOfDeclaration(";", &syntax_location));
 
   syntax_identifier_ = syntax;
-
   if (syntax != "proto2" && syntax != "proto3" &&
       !stop_after_syntax_identifier_) {
     AddError(syntax_token.line, syntax_token.column,
diff --git a/src/google/protobuf/compiler/parser_unittest.cc b/src/google/protobuf/compiler/parser_unittest.cc
index 2d681d957f..55ed7acb6f 100644
--- a/src/google/protobuf/compiler/parser_unittest.cc
+++ b/src/google/protobuf/compiler/parser_unittest.cc
@@ -264,6 +264,7 @@ TEST_F(ParserTest, WarnIfFieldNameContainsNumberImmediatelyFollowUnderscore) {
                   "song_name_1.") != std::string::npos);
 }
 
+
 // ===================================================================
 
 typedef ParserTest ParseMessageTest;
diff --git a/src/google/protobuf/descriptor.cc b/src/google/protobuf/descriptor.cc
index 5f3427dc72..139e6f892f 100644
--- a/src/google/protobuf/descriptor.cc
+++ b/src/google/protobuf/descriptor.cc
@@ -2562,7 +2562,9 @@ void FileDescriptor::CopyTo(FileDescriptorProto* proto) const {
   proto->set_name(name());
   if (!package().empty()) proto->set_package(package());
   // TODO(liujisi): Also populate when syntax="proto2".
-  if (syntax() == SYNTAX_PROTO3) proto->set_syntax(SyntaxName(syntax()));
+  if (syntax() == SYNTAX_PROTO3
+  ) proto->set_syntax(SyntaxName(syntax()));
+
 
   for (int i = 0; i < dependency_count(); i++) {
     proto->add_dependency(dependency(i)->name());
@@ -4982,7 +4984,8 @@ static void PlanAllocationSize(const FileDescriptorProto& proto,
                                internal::FlatAllocator& alloc) {
   alloc.PlanArray<FileDescriptor>(1);
   alloc.PlanArray<FileDescriptorTables>(1);
-  alloc.PlanArray<std::string>(2);  // name + package
+  alloc.PlanArray<std::string>(2
+  );  // name + package
   if (proto.has_options()) alloc.PlanArray<FileOptions>(1);
   if (proto.has_source_code_info()) alloc.PlanArray<SourceCodeInfo>(1);
 
diff --git a/src/google/protobuf/descriptor.h b/src/google/protobuf/descriptor.h
index 1b8728ec63..685e9235d8 100644
--- a/src/google/protobuf/descriptor.h
+++ b/src/google/protobuf/descriptor.h
@@ -54,6 +54,9 @@
 #ifndef GOOGLE_PROTOBUF_DESCRIPTOR_H__
 #define GOOGLE_PROTOBUF_DESCRIPTOR_H__
 
+#include <cstdint>
+
+#include <google/protobuf/stubs/strutil.h>
 
 #include <atomic>
 #include <map>
@@ -1702,7 +1705,7 @@ class PROTOBUF_EXPORT FileDescriptor : private internal::SymbolBase {
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FileDescriptor);
 };
 
-PROTOBUF_INTERNAL_CHECK_CLASS_SIZE(FileDescriptor, 144);
+PROTOBUF_INTERNAL_CHECK_CLASS_SIZE(FileDescriptor, 152);
 
 // ===================================================================
 
diff --git a/src/google/protobuf/descriptor.pb.cc b/src/google/protobuf/descriptor.pb.cc
index c77c83c1e9..2dfece5b61 100644
--- a/src/google/protobuf/descriptor.pb.cc
+++ b/src/google/protobuf/descriptor.pb.cc
@@ -48,6 +48,7 @@ PROTOBUF_CONSTEXPR FileDescriptorProto::FileDescriptorProto(
   , /*decltype(_impl_.name_)*/{&::_pbi::fixed_address_empty_string, ::_pbi::ConstantInitialized{}}
   , /*decltype(_impl_.package_)*/{&::_pbi::fixed_address_empty_string, ::_pbi::ConstantInitialized{}}
   , /*decltype(_impl_.syntax_)*/{&::_pbi::fixed_address_empty_string, ::_pbi::ConstantInitialized{}}
+  , /*decltype(_impl_.edition_)*/{&::_pbi::fixed_address_empty_string, ::_pbi::ConstantInitialized{}}
   , /*decltype(_impl_.options_)*/nullptr
   , /*decltype(_impl_.source_code_info_)*/nullptr} {}
 struct FileDescriptorProtoDefaultTypeInternal {
@@ -540,6 +541,7 @@ const uint32_t TableStruct_google_2fprotobuf_2fdescriptor_2eproto::offsets[] PRO
   PROTOBUF_FIELD_OFFSET(::PROTOBUF_NAMESPACE_ID::FileDescriptorProto, _impl_.options_),
   PROTOBUF_FIELD_OFFSET(::PROTOBUF_NAMESPACE_ID::FileDescriptorProto, _impl_.source_code_info_),
   PROTOBUF_FIELD_OFFSET(::PROTOBUF_NAMESPACE_ID::FileDescriptorProto, _impl_.syntax_),
+  PROTOBUF_FIELD_OFFSET(::PROTOBUF_NAMESPACE_ID::FileDescriptorProto, _impl_.edition_),
   0,
   1,
   ~0u,
@@ -549,9 +551,10 @@ const uint32_t TableStruct_google_2fprotobuf_2fdescriptor_2eproto::offsets[] PRO
   ~0u,
   ~0u,
   ~0u,
-  3,
   4,
+  5,
   2,
+  3,
   PROTOBUF_FIELD_OFFSET(::PROTOBUF_NAMESPACE_ID::DescriptorProto_ExtensionRange, _impl_._has_bits_),
   PROTOBUF_FIELD_OFFSET(::PROTOBUF_NAMESPACE_ID::DescriptorProto_ExtensionRange, _internal_metadata_),
   ~0u,  // no _extensions_
@@ -977,32 +980,32 @@ const uint32_t TableStruct_google_2fprotobuf_2fdescriptor_2eproto::offsets[] PRO
 };
 static const ::_pbi::MigrationSchema schemas[] PROTOBUF_SECTION_VARIABLE(protodesc_cold) = {
   { 0, -1, -1, sizeof(::PROTOBUF_NAMESPACE_ID::FileDescriptorSet)},
-  { 9, 29, -1, sizeof(::PROTOBUF_NAMESPACE_ID::FileDescriptorProto)},
-  { 41, 52, -1, sizeof(::PROTOBUF_NAMESPACE_ID::DescriptorProto_ExtensionRange)},
-  { 55, 65, -1, sizeof(::PROTOBUF_NAMESPACE_ID::DescriptorProto_ReservedRange)},
-  { 67, 85, -1, sizeof(::PROTOBUF_NAMESPACE_ID::DescriptorProto)},
-  { 95, -1, -1, sizeof(::PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions)},
-  { 104, 123, -1, sizeof(::PROTOBUF_NAMESPACE_ID::FieldDescriptorProto)},
-  { 134, 144, -1, sizeof(::PROTOBUF_NAMESPACE_ID::OneofDescriptorProto)},
-  { 146, 156, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumDescriptorProto_EnumReservedRange)},
-  { 158, 171, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumDescriptorProto)},
-  { 176, 187, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumValueDescriptorProto)},
-  { 190, 201, -1, sizeof(::PROTOBUF_NAMESPACE_ID::ServiceDescriptorProto)},
-  { 204, 218, -1, sizeof(::PROTOBUF_NAMESPACE_ID::MethodDescriptorProto)},
-  { 224, 253, -1, sizeof(::PROTOBUF_NAMESPACE_ID::FileOptions)},
-  { 274, 287, -1, sizeof(::PROTOBUF_NAMESPACE_ID::MessageOptions)},
-  { 292, 308, -1, sizeof(::PROTOBUF_NAMESPACE_ID::FieldOptions)},
-  { 316, -1, -1, sizeof(::PROTOBUF_NAMESPACE_ID::OneofOptions)},
-  { 325, 336, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumOptions)},
-  { 339, 349, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumValueOptions)},
-  { 351, 361, -1, sizeof(::PROTOBUF_NAMESPACE_ID::ServiceOptions)},
-  { 363, 374, -1, sizeof(::PROTOBUF_NAMESPACE_ID::MethodOptions)},
-  { 377, 387, -1, sizeof(::PROTOBUF_NAMESPACE_ID::UninterpretedOption_NamePart)},
-  { 389, 404, -1, sizeof(::PROTOBUF_NAMESPACE_ID::UninterpretedOption)},
-  { 411, 424, -1, sizeof(::PROTOBUF_NAMESPACE_ID::SourceCodeInfo_Location)},
-  { 429, -1, -1, sizeof(::PROTOBUF_NAMESPACE_ID::SourceCodeInfo)},
-  { 438, 450, -1, sizeof(::PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo_Annotation)},
-  { 454, -1, -1, sizeof(::PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo)},
+  { 9, 30, -1, sizeof(::PROTOBUF_NAMESPACE_ID::FileDescriptorProto)},
+  { 43, 54, -1, sizeof(::PROTOBUF_NAMESPACE_ID::DescriptorProto_ExtensionRange)},
+  { 57, 67, -1, sizeof(::PROTOBUF_NAMESPACE_ID::DescriptorProto_ReservedRange)},
+  { 69, 87, -1, sizeof(::PROTOBUF_NAMESPACE_ID::DescriptorProto)},
+  { 97, -1, -1, sizeof(::PROTOBUF_NAMESPACE_ID::ExtensionRangeOptions)},
+  { 106, 125, -1, sizeof(::PROTOBUF_NAMESPACE_ID::FieldDescriptorProto)},
+  { 136, 146, -1, sizeof(::PROTOBUF_NAMESPACE_ID::OneofDescriptorProto)},
+  { 148, 158, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumDescriptorProto_EnumReservedRange)},
+  { 160, 173, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumDescriptorProto)},
+  { 178, 189, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumValueDescriptorProto)},
+  { 192, 203, -1, sizeof(::PROTOBUF_NAMESPACE_ID::ServiceDescriptorProto)},
+  { 206, 220, -1, sizeof(::PROTOBUF_NAMESPACE_ID::MethodDescriptorProto)},
+  { 226, 255, -1, sizeof(::PROTOBUF_NAMESPACE_ID::FileOptions)},
+  { 276, 289, -1, sizeof(::PROTOBUF_NAMESPACE_ID::MessageOptions)},
+  { 294, 310, -1, sizeof(::PROTOBUF_NAMESPACE_ID::FieldOptions)},
+  { 318, -1, -1, sizeof(::PROTOBUF_NAMESPACE_ID::OneofOptions)},
+  { 327, 338, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumOptions)},
+  { 341, 351, -1, sizeof(::PROTOBUF_NAMESPACE_ID::EnumValueOptions)},
+  { 353, 363, -1, sizeof(::PROTOBUF_NAMESPACE_ID::ServiceOptions)},
+  { 365, 376, -1, sizeof(::PROTOBUF_NAMESPACE_ID::MethodOptions)},
+  { 379, 389, -1, sizeof(::PROTOBUF_NAMESPACE_ID::UninterpretedOption_NamePart)},
+  { 391, 406, -1, sizeof(::PROTOBUF_NAMESPACE_ID::UninterpretedOption)},
+  { 413, 426, -1, sizeof(::PROTOBUF_NAMESPACE_ID::SourceCodeInfo_Location)},
+  { 431, -1, -1, sizeof(::PROTOBUF_NAMESPACE_ID::SourceCodeInfo)},
+  { 440, 452, -1, sizeof(::PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo_Annotation)},
+  { 456, -1, -1, sizeof(::PROTOBUF_NAMESPACE_ID::GeneratedCodeInfo)},
 };
 
 static const ::_pb::Message* const file_default_instances[] = {
@@ -1039,7 +1042,7 @@ const char descriptor_table_protodef_google_2fprotobuf_2fdescriptor_2eproto[] PR
   "\n google/protobuf/descriptor.proto\022\017goog"
   "le.protobuf\"G\n\021FileDescriptorSet\0222\n\004file"
   "\030\001 \003(\0132$.google.protobuf.FileDescriptorP"
-  "roto\"\333\003\n\023FileDescriptorProto\022\014\n\004name\030\001 \001"
+  "roto\"\354\003\n\023FileDescriptorProto\022\014\n\004name\030\001 \001"
   "(\t\022\017\n\007package\030\002 \001(\t\022\022\n\ndependency\030\003 \003(\t\022"
   "\031\n\021public_dependency\030\n \003(\005\022\027\n\017weak_depen"
   "dency\030\013 \003(\005\0226\n\014message_type\030\004 \003(\0132 .goog"
@@ -1051,147 +1054,148 @@ const char descriptor_table_protodef_google_2fprotobuf_2fdescriptor_2eproto[] PR
   "\022-\n\007options\030\010 \001(\0132\034.google.protobuf.File"
   "Options\0229\n\020source_code_info\030\t \001(\0132\037.goog"
   "le.protobuf.SourceCodeInfo\022\016\n\006syntax\030\014 \001"
-  "(\t\"\251\005\n\017DescriptorProto\022\014\n\004name\030\001 \001(\t\0224\n\005"
-  "field\030\002 \003(\0132%.google.protobuf.FieldDescr"
-  "iptorProto\0228\n\textension\030\006 \003(\0132%.google.p"
-  "rotobuf.FieldDescriptorProto\0225\n\013nested_t"
-  "ype\030\003 \003(\0132 .google.protobuf.DescriptorPr"
-  "oto\0227\n\tenum_type\030\004 \003(\0132$.google.protobuf"
-  ".EnumDescriptorProto\022H\n\017extension_range\030"
-  "\005 \003(\0132/.google.protobuf.DescriptorProto."
-  "ExtensionRange\0229\n\noneof_decl\030\010 \003(\0132%.goo"
-  "gle.protobuf.OneofDescriptorProto\0220\n\007opt"
-  "ions\030\007 \001(\0132\037.google.protobuf.MessageOpti"
-  "ons\022F\n\016reserved_range\030\t \003(\0132..google.pro"
-  "tobuf.DescriptorProto.ReservedRange\022\025\n\rr"
-  "eserved_name\030\n \003(\t\032e\n\016ExtensionRange\022\r\n\005"
-  "start\030\001 \001(\005\022\013\n\003end\030\002 \001(\005\0227\n\007options\030\003 \001("
-  "\0132&.google.protobuf.ExtensionRangeOption"
-  "s\032+\n\rReservedRange\022\r\n\005start\030\001 \001(\005\022\013\n\003end"
-  "\030\002 \001(\005\"g\n\025ExtensionRangeOptions\022C\n\024unint"
-  "erpreted_option\030\347\007 \003(\0132$.google.protobuf"
-  ".UninterpretedOption*\t\010\350\007\020\200\200\200\200\002\"\325\005\n\024Fiel"
-  "dDescriptorProto\022\014\n\004name\030\001 \001(\t\022\016\n\006number"
-  "\030\003 \001(\005\022:\n\005label\030\004 \001(\0162+.google.protobuf."
-  "FieldDescriptorProto.Label\0228\n\004type\030\005 \001(\016"
-  "2*.google.protobuf.FieldDescriptorProto."
-  "Type\022\021\n\ttype_name\030\006 \001(\t\022\020\n\010extendee\030\002 \001("
-  "\t\022\025\n\rdefault_value\030\007 \001(\t\022\023\n\013oneof_index\030"
-  "\t \001(\005\022\021\n\tjson_name\030\n \001(\t\022.\n\007options\030\010 \001("
-  "\0132\035.google.protobuf.FieldOptions\022\027\n\017prot"
-  "o3_optional\030\021 \001(\010\"\266\002\n\004Type\022\017\n\013TYPE_DOUBL"
-  "E\020\001\022\016\n\nTYPE_FLOAT\020\002\022\016\n\nTYPE_INT64\020\003\022\017\n\013T"
-  "YPE_UINT64\020\004\022\016\n\nTYPE_INT32\020\005\022\020\n\014TYPE_FIX"
-  "ED64\020\006\022\020\n\014TYPE_FIXED32\020\007\022\r\n\tTYPE_BOOL\020\010\022"
-  "\017\n\013TYPE_STRING\020\t\022\016\n\nTYPE_GROUP\020\n\022\020\n\014TYPE"
-  "_MESSAGE\020\013\022\016\n\nTYPE_BYTES\020\014\022\017\n\013TYPE_UINT3"
-  "2\020\r\022\r\n\tTYPE_ENUM\020\016\022\021\n\rTYPE_SFIXED32\020\017\022\021\n"
-  "\rTYPE_SFIXED64\020\020\022\017\n\013TYPE_SINT32\020\021\022\017\n\013TYP"
-  "E_SINT64\020\022\"C\n\005Label\022\022\n\016LABEL_OPTIONAL\020\001\022"
-  "\022\n\016LABEL_REQUIRED\020\002\022\022\n\016LABEL_REPEATED\020\003\""
-  "T\n\024OneofDescriptorProto\022\014\n\004name\030\001 \001(\t\022.\n"
-  "\007options\030\002 \001(\0132\035.google.protobuf.OneofOp"
-  "tions\"\244\002\n\023EnumDescriptorProto\022\014\n\004name\030\001 "
-  "\001(\t\0228\n\005value\030\002 \003(\0132).google.protobuf.Enu"
-  "mValueDescriptorProto\022-\n\007options\030\003 \001(\0132\034"
-  ".google.protobuf.EnumOptions\022N\n\016reserved"
-  "_range\030\004 \003(\01326.google.protobuf.EnumDescr"
-  "iptorProto.EnumReservedRange\022\025\n\rreserved"
-  "_name\030\005 \003(\t\032/\n\021EnumReservedRange\022\r\n\005star"
-  "t\030\001 \001(\005\022\013\n\003end\030\002 \001(\005\"l\n\030EnumValueDescrip"
-  "torProto\022\014\n\004name\030\001 \001(\t\022\016\n\006number\030\002 \001(\005\0222"
-  "\n\007options\030\003 \001(\0132!.google.protobuf.EnumVa"
-  "lueOptions\"\220\001\n\026ServiceDescriptorProto\022\014\n"
-  "\004name\030\001 \001(\t\0226\n\006method\030\002 \003(\0132&.google.pro"
-  "tobuf.MethodDescriptorProto\0220\n\007options\030\003"
-  " \001(\0132\037.google.protobuf.ServiceOptions\"\301\001"
-  "\n\025MethodDescriptorProto\022\014\n\004name\030\001 \001(\t\022\022\n"
-  "\ninput_type\030\002 \001(\t\022\023\n\013output_type\030\003 \001(\t\022/"
-  "\n\007options\030\004 \001(\0132\036.google.protobuf.Method"
-  "Options\022\037\n\020client_streaming\030\005 \001(\010:\005false"
-  "\022\037\n\020server_streaming\030\006 \001(\010:\005false\"\245\006\n\013Fi"
-  "leOptions\022\024\n\014java_package\030\001 \001(\t\022\034\n\024java_"
-  "outer_classname\030\010 \001(\t\022\"\n\023java_multiple_f"
-  "iles\030\n \001(\010:\005false\022)\n\035java_generate_equal"
-  "s_and_hash\030\024 \001(\010B\002\030\001\022%\n\026java_string_chec"
-  "k_utf8\030\033 \001(\010:\005false\022F\n\014optimize_for\030\t \001("
-  "\0162).google.protobuf.FileOptions.Optimize"
-  "Mode:\005SPEED\022\022\n\ngo_package\030\013 \001(\t\022\"\n\023cc_ge"
-  "neric_services\030\020 \001(\010:\005false\022$\n\025java_gene"
-  "ric_services\030\021 \001(\010:\005false\022\"\n\023py_generic_"
-  "services\030\022 \001(\010:\005false\022#\n\024php_generic_ser"
-  "vices\030* \001(\010:\005false\022\031\n\ndeprecated\030\027 \001(\010:\005"
-  "false\022\036\n\020cc_enable_arenas\030\037 \001(\010:\004true\022\031\n"
-  "\021objc_class_prefix\030$ \001(\t\022\030\n\020csharp_names"
-  "pace\030% \001(\t\022\024\n\014swift_prefix\030\' \001(\t\022\030\n\020php_"
-  "class_prefix\030( \001(\t\022\025\n\rphp_namespace\030) \001("
-  "\t\022\036\n\026php_metadata_namespace\030, \001(\t\022\024\n\014rub"
-  "y_package\030- \001(\t\022C\n\024uninterpreted_option\030"
-  "\347\007 \003(\0132$.google.protobuf.UninterpretedOp"
-  "tion\":\n\014OptimizeMode\022\t\n\005SPEED\020\001\022\r\n\tCODE_"
-  "SIZE\020\002\022\020\n\014LITE_RUNTIME\020\003*\t\010\350\007\020\200\200\200\200\002J\004\010&\020"
-  "\'\"\204\002\n\016MessageOptions\022&\n\027message_set_wire"
-  "_format\030\001 \001(\010:\005false\022.\n\037no_standard_desc"
-  "riptor_accessor\030\002 \001(\010:\005false\022\031\n\ndeprecat"
-  "ed\030\003 \001(\010:\005false\022\021\n\tmap_entry\030\007 \001(\010\022C\n\024un"
-  "interpreted_option\030\347\007 \003(\0132$.google.proto"
-  "buf.UninterpretedOption*\t\010\350\007\020\200\200\200\200\002J\004\010\004\020\005"
-  "J\004\010\005\020\006J\004\010\006\020\007J\004\010\010\020\tJ\004\010\t\020\n\"\276\003\n\014FieldOption"
-  "s\022:\n\005ctype\030\001 \001(\0162#.google.protobuf.Field"
-  "Options.CType:\006STRING\022\016\n\006packed\030\002 \001(\010\022\?\n"
-  "\006jstype\030\006 \001(\0162$.google.protobuf.FieldOpt"
-  "ions.JSType:\tJS_NORMAL\022\023\n\004lazy\030\005 \001(\010:\005fa"
-  "lse\022\036\n\017unverified_lazy\030\017 \001(\010:\005false\022\031\n\nd"
-  "eprecated\030\003 \001(\010:\005false\022\023\n\004weak\030\n \001(\010:\005fa"
-  "lse\022C\n\024uninterpreted_option\030\347\007 \003(\0132$.goo"
-  "gle.protobuf.UninterpretedOption\"/\n\005CTyp"
-  "e\022\n\n\006STRING\020\000\022\010\n\004CORD\020\001\022\020\n\014STRING_PIECE\020"
-  "\002\"5\n\006JSType\022\r\n\tJS_NORMAL\020\000\022\r\n\tJS_STRING\020"
-  "\001\022\r\n\tJS_NUMBER\020\002*\t\010\350\007\020\200\200\200\200\002J\004\010\004\020\005\"^\n\014One"
-  "ofOptions\022C\n\024uninterpreted_option\030\347\007 \003(\013"
-  "2$.google.protobuf.UninterpretedOption*\t"
-  "\010\350\007\020\200\200\200\200\002\"\223\001\n\013EnumOptions\022\023\n\013allow_alias"
-  "\030\002 \001(\010\022\031\n\ndeprecated\030\003 \001(\010:\005false\022C\n\024uni"
-  "nterpreted_option\030\347\007 \003(\0132$.google.protob"
-  "uf.UninterpretedOption*\t\010\350\007\020\200\200\200\200\002J\004\010\005\020\006\""
-  "}\n\020EnumValueOptions\022\031\n\ndeprecated\030\001 \001(\010:"
-  "\005false\022C\n\024uninterpreted_option\030\347\007 \003(\0132$."
-  "google.protobuf.UninterpretedOption*\t\010\350\007"
-  "\020\200\200\200\200\002\"{\n\016ServiceOptions\022\031\n\ndeprecated\030!"
-  " \001(\010:\005false\022C\n\024uninterpreted_option\030\347\007 \003"
+  "(\t\022\017\n\007edition\030\r \001(\t\"\251\005\n\017DescriptorProto\022"
+  "\014\n\004name\030\001 \001(\t\0224\n\005field\030\002 \003(\0132%.google.pr"
+  "otobuf.FieldDescriptorProto\0228\n\textension"
+  "\030\006 \003(\0132%.google.protobuf.FieldDescriptor"
+  "Proto\0225\n\013nested_type\030\003 \003(\0132 .google.prot"
+  "obuf.DescriptorProto\0227\n\tenum_type\030\004 \003(\0132"
+  "$.google.protobuf.EnumDescriptorProto\022H\n"
+  "\017extension_range\030\005 \003(\0132/.google.protobuf"
+  ".DescriptorProto.ExtensionRange\0229\n\noneof"
+  "_decl\030\010 \003(\0132%.google.protobuf.OneofDescr"
+  "iptorProto\0220\n\007options\030\007 \001(\0132\037.google.pro"
+  "tobuf.MessageOptions\022F\n\016reserved_range\030\t"
+  " \003(\0132..google.protobuf.DescriptorProto.R"
+  "eservedRange\022\025\n\rreserved_name\030\n \003(\t\032e\n\016E"
+  "xtensionRange\022\r\n\005start\030\001 \001(\005\022\013\n\003end\030\002 \001("
+  "\005\0227\n\007options\030\003 \001(\0132&.google.protobuf.Ext"
+  "ensionRangeOptions\032+\n\rReservedRange\022\r\n\005s"
+  "tart\030\001 \001(\005\022\013\n\003end\030\002 \001(\005\"g\n\025ExtensionRang"
+  "eOptions\022C\n\024uninterpreted_option\030\347\007 \003(\0132"
+  "$.google.protobuf.UninterpretedOption*\t\010"
+  "\350\007\020\200\200\200\200\002\"\325\005\n\024FieldDescriptorProto\022\014\n\004nam"
+  "e\030\001 \001(\t\022\016\n\006number\030\003 \001(\005\022:\n\005label\030\004 \001(\0162+"
+  ".google.protobuf.FieldDescriptorProto.La"
+  "bel\0228\n\004type\030\005 \001(\0162*.google.protobuf.Fiel"
+  "dDescriptorProto.Type\022\021\n\ttype_name\030\006 \001(\t"
+  "\022\020\n\010extendee\030\002 \001(\t\022\025\n\rdefault_value\030\007 \001("
+  "\t\022\023\n\013oneof_index\030\t \001(\005\022\021\n\tjson_name\030\n \001("
+  "\t\022.\n\007options\030\010 \001(\0132\035.google.protobuf.Fie"
+  "ldOptions\022\027\n\017proto3_optional\030\021 \001(\010\"\266\002\n\004T"
+  "ype\022\017\n\013TYPE_DOUBLE\020\001\022\016\n\nTYPE_FLOAT\020\002\022\016\n\n"
+  "TYPE_INT64\020\003\022\017\n\013TYPE_UINT64\020\004\022\016\n\nTYPE_IN"
+  "T32\020\005\022\020\n\014TYPE_FIXED64\020\006\022\020\n\014TYPE_FIXED32\020"
+  "\007\022\r\n\tTYPE_BOOL\020\010\022\017\n\013TYPE_STRING\020\t\022\016\n\nTYP"
+  "E_GROUP\020\n\022\020\n\014TYPE_MESSAGE\020\013\022\016\n\nTYPE_BYTE"
+  "S\020\014\022\017\n\013TYPE_UINT32\020\r\022\r\n\tTYPE_ENUM\020\016\022\021\n\rT"
+  "YPE_SFIXED32\020\017\022\021\n\rTYPE_SFIXED64\020\020\022\017\n\013TYP"
+  "E_SINT32\020\021\022\017\n\013TYPE_SINT64\020\022\"C\n\005Label\022\022\n\016"
+  "LABEL_OPTIONAL\020\001\022\022\n\016LABEL_REQUIRED\020\002\022\022\n\016"
+  "LABEL_REPEATED\020\003\"T\n\024OneofDescriptorProto"
+  "\022\014\n\004name\030\001 \001(\t\022.\n\007options\030\002 \001(\0132\035.google"
+  ".protobuf.OneofOptions\"\244\002\n\023EnumDescripto"
+  "rProto\022\014\n\004name\030\001 \001(\t\0228\n\005value\030\002 \003(\0132).go"
+  "ogle.protobuf.EnumValueDescriptorProto\022-"
+  "\n\007options\030\003 \001(\0132\034.google.protobuf.EnumOp"
+  "tions\022N\n\016reserved_range\030\004 \003(\01326.google.p"
+  "rotobuf.EnumDescriptorProto.EnumReserved"
+  "Range\022\025\n\rreserved_name\030\005 \003(\t\032/\n\021EnumRese"
+  "rvedRange\022\r\n\005start\030\001 \001(\005\022\013\n\003end\030\002 \001(\005\"l\n"
+  "\030EnumValueDescriptorProto\022\014\n\004name\030\001 \001(\t\022"
+  "\016\n\006number\030\002 \001(\005\0222\n\007options\030\003 \001(\0132!.googl"
+  "e.protobuf.EnumValueOptions\"\220\001\n\026ServiceD"
+  "escriptorProto\022\014\n\004name\030\001 \001(\t\0226\n\006method\030\002"
+  " \003(\0132&.google.protobuf.MethodDescriptorP"
+  "roto\0220\n\007options\030\003 \001(\0132\037.google.protobuf."
+  "ServiceOptions\"\301\001\n\025MethodDescriptorProto"
+  "\022\014\n\004name\030\001 \001(\t\022\022\n\ninput_type\030\002 \001(\t\022\023\n\013ou"
+  "tput_type\030\003 \001(\t\022/\n\007options\030\004 \001(\0132\036.googl"
+  "e.protobuf.MethodOptions\022\037\n\020client_strea"
+  "ming\030\005 \001(\010:\005false\022\037\n\020server_streaming\030\006 "
+  "\001(\010:\005false\"\245\006\n\013FileOptions\022\024\n\014java_packa"
+  "ge\030\001 \001(\t\022\034\n\024java_outer_classname\030\010 \001(\t\022\""
+  "\n\023java_multiple_files\030\n \001(\010:\005false\022)\n\035ja"
+  "va_generate_equals_and_hash\030\024 \001(\010B\002\030\001\022%\n"
+  "\026java_string_check_utf8\030\033 \001(\010:\005false\022F\n\014"
+  "optimize_for\030\t \001(\0162).google.protobuf.Fil"
+  "eOptions.OptimizeMode:\005SPEED\022\022\n\ngo_packa"
+  "ge\030\013 \001(\t\022\"\n\023cc_generic_services\030\020 \001(\010:\005f"
+  "alse\022$\n\025java_generic_services\030\021 \001(\010:\005fal"
+  "se\022\"\n\023py_generic_services\030\022 \001(\010:\005false\022#"
+  "\n\024php_generic_services\030* \001(\010:\005false\022\031\n\nd"
+  "eprecated\030\027 \001(\010:\005false\022\036\n\020cc_enable_aren"
+  "as\030\037 \001(\010:\004true\022\031\n\021objc_class_prefix\030$ \001("
+  "\t\022\030\n\020csharp_namespace\030% \001(\t\022\024\n\014swift_pre"
+  "fix\030\' \001(\t\022\030\n\020php_class_prefix\030( \001(\t\022\025\n\rp"
+  "hp_namespace\030) \001(\t\022\036\n\026php_metadata_names"
+  "pace\030, \001(\t\022\024\n\014ruby_package\030- \001(\t\022C\n\024unin"
+  "terpreted_option\030\347\007 \003(\0132$.google.protobu"
+  "f.UninterpretedOption\":\n\014OptimizeMode\022\t\n"
+  "\005SPEED\020\001\022\r\n\tCODE_SIZE\020\002\022\020\n\014LITE_RUNTIME\020"
+  "\003*\t\010\350\007\020\200\200\200\200\002J\004\010&\020\'\"\204\002\n\016MessageOptions\022&\n"
+  "\027message_set_wire_format\030\001 \001(\010:\005false\022.\n"
+  "\037no_standard_descriptor_accessor\030\002 \001(\010:\005"
+  "false\022\031\n\ndeprecated\030\003 \001(\010:\005false\022\021\n\tmap_"
+  "entry\030\007 \001(\010\022C\n\024uninterpreted_option\030\347\007 \003"
   "(\0132$.google.protobuf.UninterpretedOption"
-  "*\t\010\350\007\020\200\200\200\200\002\"\255\002\n\rMethodOptions\022\031\n\ndepreca"
-  "ted\030! \001(\010:\005false\022_\n\021idempotency_level\030\" "
-  "\001(\0162/.google.protobuf.MethodOptions.Idem"
-  "potencyLevel:\023IDEMPOTENCY_UNKNOWN\022C\n\024uni"
-  "nterpreted_option\030\347\007 \003(\0132$.google.protob"
-  "uf.UninterpretedOption\"P\n\020IdempotencyLev"
-  "el\022\027\n\023IDEMPOTENCY_UNKNOWN\020\000\022\023\n\017NO_SIDE_E"
-  "FFECTS\020\001\022\016\n\nIDEMPOTENT\020\002*\t\010\350\007\020\200\200\200\200\002\"\236\002\n\023"
-  "UninterpretedOption\022;\n\004name\030\002 \003(\0132-.goog"
-  "le.protobuf.UninterpretedOption.NamePart"
-  "\022\030\n\020identifier_value\030\003 \001(\t\022\032\n\022positive_i"
-  "nt_value\030\004 \001(\004\022\032\n\022negative_int_value\030\005 \001"
-  "(\003\022\024\n\014double_value\030\006 \001(\001\022\024\n\014string_value"
-  "\030\007 \001(\014\022\027\n\017aggregate_value\030\010 \001(\t\0323\n\010NameP"
-  "art\022\021\n\tname_part\030\001 \002(\t\022\024\n\014is_extension\030\002"
-  " \002(\010\"\325\001\n\016SourceCodeInfo\022:\n\010location\030\001 \003("
-  "\0132(.google.protobuf.SourceCodeInfo.Locat"
-  "ion\032\206\001\n\010Location\022\020\n\004path\030\001 \003(\005B\002\020\001\022\020\n\004sp"
-  "an\030\002 \003(\005B\002\020\001\022\030\n\020leading_comments\030\003 \001(\t\022\031"
-  "\n\021trailing_comments\030\004 \001(\t\022!\n\031leading_det"
-  "ached_comments\030\006 \003(\t\"\247\001\n\021GeneratedCodeIn"
-  "fo\022A\n\nannotation\030\001 \003(\0132-.google.protobuf"
-  ".GeneratedCodeInfo.Annotation\032O\n\nAnnotat"
-  "ion\022\020\n\004path\030\001 \003(\005B\002\020\001\022\023\n\013source_file\030\002 \001"
-  "(\t\022\r\n\005begin\030\003 \001(\005\022\013\n\003end\030\004 \001(\005B~\n\023com.go"
-  "ogle.protobufB\020DescriptorProtosH\001Z-googl"
-  "e.golang.org/protobuf/types/descriptorpb"
-  "\370\001\001\242\002\003GPB\252\002\032Google.Protobuf.Reflection"
+  "*\t\010\350\007\020\200\200\200\200\002J\004\010\004\020\005J\004\010\005\020\006J\004\010\006\020\007J\004\010\010\020\tJ\004\010\t\020"
+  "\n\"\276\003\n\014FieldOptions\022:\n\005ctype\030\001 \001(\0162#.goog"
+  "le.protobuf.FieldOptions.CType:\006STRING\022\016"
+  "\n\006packed\030\002 \001(\010\022\?\n\006jstype\030\006 \001(\0162$.google."
+  "protobuf.FieldOptions.JSType:\tJS_NORMAL\022"
+  "\023\n\004lazy\030\005 \001(\010:\005false\022\036\n\017unverified_lazy\030"
+  "\017 \001(\010:\005false\022\031\n\ndeprecated\030\003 \001(\010:\005false\022"
+  "\023\n\004weak\030\n \001(\010:\005false\022C\n\024uninterpreted_op"
+  "tion\030\347\007 \003(\0132$.google.protobuf.Uninterpre"
+  "tedOption\"/\n\005CType\022\n\n\006STRING\020\000\022\010\n\004CORD\020\001"
+  "\022\020\n\014STRING_PIECE\020\002\"5\n\006JSType\022\r\n\tJS_NORMA"
+  "L\020\000\022\r\n\tJS_STRING\020\001\022\r\n\tJS_NUMBER\020\002*\t\010\350\007\020\200"
+  "\200\200\200\002J\004\010\004\020\005\"^\n\014OneofOptions\022C\n\024uninterpre"
+  "ted_option\030\347\007 \003(\0132$.google.protobuf.Unin"
+  "terpretedOption*\t\010\350\007\020\200\200\200\200\002\"\223\001\n\013EnumOptio"
+  "ns\022\023\n\013allow_alias\030\002 \001(\010\022\031\n\ndeprecated\030\003 "
+  "\001(\010:\005false\022C\n\024uninterpreted_option\030\347\007 \003("
+  "\0132$.google.protobuf.UninterpretedOption*"
+  "\t\010\350\007\020\200\200\200\200\002J\004\010\005\020\006\"}\n\020EnumValueOptions\022\031\n\n"
+  "deprecated\030\001 \001(\010:\005false\022C\n\024uninterpreted"
+  "_option\030\347\007 \003(\0132$.google.protobuf.Uninter"
+  "pretedOption*\t\010\350\007\020\200\200\200\200\002\"{\n\016ServiceOption"
+  "s\022\031\n\ndeprecated\030! \001(\010:\005false\022C\n\024uninterp"
+  "reted_option\030\347\007 \003(\0132$.google.protobuf.Un"
+  "interpretedOption*\t\010\350\007\020\200\200\200\200\002\"\255\002\n\rMethodO"
+  "ptions\022\031\n\ndeprecated\030! \001(\010:\005false\022_\n\021ide"
+  "mpotency_level\030\" \001(\0162/.google.protobuf.M"
+  "ethodOptions.IdempotencyLevel:\023IDEMPOTEN"
+  "CY_UNKNOWN\022C\n\024uninterpreted_option\030\347\007 \003("
+  "\0132$.google.protobuf.UninterpretedOption\""
+  "P\n\020IdempotencyLevel\022\027\n\023IDEMPOTENCY_UNKNO"
+  "WN\020\000\022\023\n\017NO_SIDE_EFFECTS\020\001\022\016\n\nIDEMPOTENT\020"
+  "\002*\t\010\350\007\020\200\200\200\200\002\"\236\002\n\023UninterpretedOption\022;\n\004"
+  "name\030\002 \003(\0132-.google.protobuf.Uninterpret"
+  "edOption.NamePart\022\030\n\020identifier_value\030\003 "
+  "\001(\t\022\032\n\022positive_int_value\030\004 \001(\004\022\032\n\022negat"
+  "ive_int_value\030\005 \001(\003\022\024\n\014double_value\030\006 \001("
+  "\001\022\024\n\014string_value\030\007 \001(\014\022\027\n\017aggregate_val"
+  "ue\030\010 \001(\t\0323\n\010NamePart\022\021\n\tname_part\030\001 \002(\t\022"
+  "\024\n\014is_extension\030\002 \002(\010\"\325\001\n\016SourceCodeInfo"
+  "\022:\n\010location\030\001 \003(\0132(.google.protobuf.Sou"
+  "rceCodeInfo.Location\032\206\001\n\010Location\022\020\n\004pat"
+  "h\030\001 \003(\005B\002\020\001\022\020\n\004span\030\002 \003(\005B\002\020\001\022\030\n\020leading"
+  "_comments\030\003 \001(\t\022\031\n\021trailing_comments\030\004 \001"
+  "(\t\022!\n\031leading_detached_comments\030\006 \003(\t\"\247\001"
+  "\n\021GeneratedCodeInfo\022A\n\nannotation\030\001 \003(\0132"
+  "-.google.protobuf.GeneratedCodeInfo.Anno"
+  "tation\032O\n\nAnnotation\022\020\n\004path\030\001 \003(\005B\002\020\001\022\023"
+  "\n\013source_file\030\002 \001(\t\022\r\n\005begin\030\003 \001(\005\022\013\n\003en"
+  "d\030\004 \001(\005B~\n\023com.google.protobufB\020Descript"
+  "orProtosH\001Z-google.golang.org/protobuf/t"
+  "ypes/descriptorpb\370\001\001\242\002\003GPB\252\002\032Google.Prot"
+  "obuf.Reflection"
   ;
 static ::_pbi::once_flag descriptor_table_google_2fprotobuf_2fdescriptor_2eproto_once;
 const ::_pbi::DescriptorTable descriptor_table_google_2fprotobuf_2fdescriptor_2eproto = {
-    false, false, 6078, descriptor_table_protodef_google_2fprotobuf_2fdescriptor_2eproto,
+    false, false, 6095, descriptor_table_protodef_google_2fprotobuf_2fdescriptor_2eproto,
     "google/protobuf/descriptor.proto",
     &descriptor_table_google_2fprotobuf_2fdescriptor_2eproto_once, nullptr, 0, 27,
     schemas, file_default_instances, TableStruct_google_2fprotobuf_2fdescriptor_2eproto::offsets,
@@ -1576,15 +1580,18 @@ class FileDescriptorProto::_Internal {
   }
   static const ::PROTOBUF_NAMESPACE_ID::FileOptions& options(const FileDescriptorProto* msg);
   static void set_has_options(HasBits* has_bits) {
-    (*has_bits)[0] |= 8u;
+    (*has_bits)[0] |= 16u;
   }
   static const ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo& source_code_info(const FileDescriptorProto* msg);
   static void set_has_source_code_info(HasBits* has_bits) {
-    (*has_bits)[0] |= 16u;
+    (*has_bits)[0] |= 32u;
   }
   static void set_has_syntax(HasBits* has_bits) {
     (*has_bits)[0] |= 4u;
   }
+  static void set_has_edition(HasBits* has_bits) {
+    (*has_bits)[0] |= 8u;
+  }
 };
 
 const ::PROTOBUF_NAMESPACE_ID::FileOptions&
@@ -1617,6 +1624,7 @@ FileDescriptorProto::FileDescriptorProto(const FileDescriptorProto& from)
     , decltype(_impl_.name_){}
     , decltype(_impl_.package_){}
     , decltype(_impl_.syntax_){}
+    , decltype(_impl_.edition_){}
     , decltype(_impl_.options_){nullptr}
     , decltype(_impl_.source_code_info_){nullptr}};
 
@@ -1645,6 +1653,14 @@ FileDescriptorProto::FileDescriptorProto(const FileDescriptorProto& from)
     _this->_impl_.syntax_.Set(from._internal_syntax(), 
       _this->GetArenaForAllocation());
   }
+  _impl_.edition_.InitDefault();
+  #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
+    _impl_.edition_.Set("", GetArenaForAllocation());
+  #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
+  if (from._internal_has_edition()) {
+    _this->_impl_.edition_.Set(from._internal_edition(), 
+      _this->GetArenaForAllocation());
+  }
   if (from._internal_has_options()) {
     _this->_impl_.options_ = new ::PROTOBUF_NAMESPACE_ID::FileOptions(*from._impl_.options_);
   }
@@ -1671,6 +1687,7 @@ inline void FileDescriptorProto::SharedCtor(
     , decltype(_impl_.name_){}
     , decltype(_impl_.package_){}
     , decltype(_impl_.syntax_){}
+    , decltype(_impl_.edition_){}
     , decltype(_impl_.options_){nullptr}
     , decltype(_impl_.source_code_info_){nullptr}
   };
@@ -1686,6 +1703,10 @@ inline void FileDescriptorProto::SharedCtor(
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
     _impl_.syntax_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
+  _impl_.edition_.InitDefault();
+  #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
+    _impl_.edition_.Set("", GetArenaForAllocation());
+  #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 }
 
 FileDescriptorProto::~FileDescriptorProto() {
@@ -1709,6 +1730,7 @@ inline void FileDescriptorProto::SharedDtor() {
   _impl_.name_.Destroy();
   _impl_.package_.Destroy();
   _impl_.syntax_.Destroy();
+  _impl_.edition_.Destroy();
   if (this != internal_default_instance()) delete _impl_.options_;
   if (this != internal_default_instance()) delete _impl_.source_code_info_;
 }
@@ -1731,7 +1753,7 @@ void FileDescriptorProto::Clear() {
   _impl_.public_dependency_.Clear();
   _impl_.weak_dependency_.Clear();
   cached_has_bits = _impl_._has_bits_[0];
-  if (cached_has_bits & 0x0000001fu) {
+  if (cached_has_bits & 0x0000003fu) {
     if (cached_has_bits & 0x00000001u) {
       _impl_.name_.ClearNonDefaultToEmpty();
     }
@@ -1742,10 +1764,13 @@ void FileDescriptorProto::Clear() {
       _impl_.syntax_.ClearNonDefaultToEmpty();
     }
     if (cached_has_bits & 0x00000008u) {
+      _impl_.edition_.ClearNonDefaultToEmpty();
+    }
+    if (cached_has_bits & 0x00000010u) {
       GOOGLE_DCHECK(_impl_.options_ != nullptr);
       _impl_.options_->Clear();
     }
-    if (cached_has_bits & 0x00000010u) {
+    if (cached_has_bits & 0x00000020u) {
       GOOGLE_DCHECK(_impl_.source_code_info_ != nullptr);
       _impl_.source_code_info_->Clear();
     }
@@ -1914,6 +1939,18 @@ const char* FileDescriptorProto::_InternalParse(const char* ptr, ::_pbi::ParseCo
         } else
           goto handle_unusual;
         continue;
+      // optional string edition = 13;
+      case 13:
+        if (PROTOBUF_PREDICT_TRUE(static_cast<uint8_t>(tag) == 106)) {
+          auto str = _internal_mutable_edition();
+          ptr = ::_pbi::InlineGreedyStringParser(str, ptr, ctx);
+          CHK_(ptr);
+          #ifndef NDEBUG
+          ::_pbi::VerifyUTF8(str, "google.protobuf.FileDescriptorProto.edition");
+          #endif  // !NDEBUG
+        } else
+          goto handle_unusual;
+        continue;
       default:
         goto handle_unusual;
     }  // switch
@@ -2008,14 +2045,14 @@ uint8_t* FileDescriptorProto::_InternalSerialize(
   }
 
   // optional .google.protobuf.FileOptions options = 8;
-  if (cached_has_bits & 0x00000008u) {
+  if (cached_has_bits & 0x00000010u) {
     target = ::PROTOBUF_NAMESPACE_ID::internal::WireFormatLite::
       InternalWriteMessage(8, _Internal::options(this),
         _Internal::options(this).GetCachedSize(), target, stream);
   }
 
   // optional .google.protobuf.SourceCodeInfo source_code_info = 9;
-  if (cached_has_bits & 0x00000010u) {
+  if (cached_has_bits & 0x00000020u) {
     target = ::PROTOBUF_NAMESPACE_ID::internal::WireFormatLite::
       InternalWriteMessage(9, _Internal::source_code_info(this),
         _Internal::source_code_info(this).GetCachedSize(), target, stream);
@@ -2043,6 +2080,16 @@ uint8_t* FileDescriptorProto::_InternalSerialize(
         12, this->_internal_syntax(), target);
   }
 
+  // optional string edition = 13;
+  if (cached_has_bits & 0x00000008u) {
+    ::PROTOBUF_NAMESPACE_ID::internal::WireFormat::VerifyUTF8StringNamedField(
+      this->_internal_edition().data(), static_cast<int>(this->_internal_edition().length()),
+      ::PROTOBUF_NAMESPACE_ID::internal::WireFormat::SERIALIZE,
+      "google.protobuf.FileDescriptorProto.edition");
+    target = stream->WriteStringMaybeAliased(
+        13, this->_internal_edition(), target);
+  }
+
   if (PROTOBUF_PREDICT_FALSE(_internal_metadata_.have_unknown_fields())) {
     target = ::_pbi::WireFormat::InternalSerializeUnknownFieldsToArray(
         _internal_metadata_.unknown_fields<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(::PROTOBUF_NAMESPACE_ID::UnknownFieldSet::default_instance), target, stream);
@@ -2114,7 +2161,7 @@ size_t FileDescriptorProto::ByteSizeLong() const {
   }
 
   cached_has_bits = _impl_._has_bits_[0];
-  if (cached_has_bits & 0x0000001fu) {
+  if (cached_has_bits & 0x0000003fu) {
     // optional string name = 1;
     if (cached_has_bits & 0x00000001u) {
       total_size += 1 +
@@ -2136,15 +2183,22 @@ size_t FileDescriptorProto::ByteSizeLong() const {
           this->_internal_syntax());
     }
 
-    // optional .google.protobuf.FileOptions options = 8;
+    // optional string edition = 13;
     if (cached_has_bits & 0x00000008u) {
+      total_size += 1 +
+        ::PROTOBUF_NAMESPACE_ID::internal::WireFormatLite::StringSize(
+          this->_internal_edition());
+    }
+
+    // optional .google.protobuf.FileOptions options = 8;
+    if (cached_has_bits & 0x00000010u) {
       total_size += 1 +
         ::PROTOBUF_NAMESPACE_ID::internal::WireFormatLite::MessageSize(
           *_impl_.options_);
     }
 
     // optional .google.protobuf.SourceCodeInfo source_code_info = 9;
-    if (cached_has_bits & 0x00000010u) {
+    if (cached_has_bits & 0x00000020u) {
       total_size += 1 +
         ::PROTOBUF_NAMESPACE_ID::internal::WireFormatLite::MessageSize(
           *_impl_.source_code_info_);
@@ -2177,7 +2231,7 @@ void FileDescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message& to_msg, co
   _this->_impl_.public_dependency_.MergeFrom(from._impl_.public_dependency_);
   _this->_impl_.weak_dependency_.MergeFrom(from._impl_.weak_dependency_);
   cached_has_bits = from._impl_._has_bits_[0];
-  if (cached_has_bits & 0x0000001fu) {
+  if (cached_has_bits & 0x0000003fu) {
     if (cached_has_bits & 0x00000001u) {
       _this->_internal_set_name(from._internal_name());
     }
@@ -2188,10 +2242,13 @@ void FileDescriptorProto::MergeImpl(::PROTOBUF_NAMESPACE_ID::Message& to_msg, co
       _this->_internal_set_syntax(from._internal_syntax());
     }
     if (cached_has_bits & 0x00000008u) {
+      _this->_internal_set_edition(from._internal_edition());
+    }
+    if (cached_has_bits & 0x00000010u) {
       _this->_internal_mutable_options()->::PROTOBUF_NAMESPACE_ID::FileOptions::MergeFrom(
           from._internal_options());
     }
-    if (cached_has_bits & 0x00000010u) {
+    if (cached_has_bits & 0x00000020u) {
       _this->_internal_mutable_source_code_info()->::PROTOBUF_NAMESPACE_ID::SourceCodeInfo::MergeFrom(
           from._internal_source_code_info());
     }
@@ -2246,6 +2303,10 @@ void FileDescriptorProto::InternalSwap(FileDescriptorProto* other) {
       &_impl_.syntax_, lhs_arena,
       &other->_impl_.syntax_, rhs_arena
   );
+  ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
+      &_impl_.edition_, lhs_arena,
+      &other->_impl_.edition_, rhs_arena
+  );
   ::PROTOBUF_NAMESPACE_ID::internal::memswap<
       PROTOBUF_FIELD_OFFSET(FileDescriptorProto, _impl_.source_code_info_)
       + sizeof(FileDescriptorProto::_impl_.source_code_info_)
diff --git a/src/google/protobuf/descriptor.pb.h b/src/google/protobuf/descriptor.pb.h
index 84e40775ea..8a23a88f9e 100644
--- a/src/google/protobuf/descriptor.pb.h
+++ b/src/google/protobuf/descriptor.pb.h
@@ -622,6 +622,7 @@ class PROTOBUF_EXPORT FileDescriptorProto final :
     kNameFieldNumber = 1,
     kPackageFieldNumber = 2,
     kSyntaxFieldNumber = 12,
+    kEditionFieldNumber = 13,
     kOptionsFieldNumber = 8,
     kSourceCodeInfoFieldNumber = 9,
   };
@@ -819,6 +820,24 @@ class PROTOBUF_EXPORT FileDescriptorProto final :
   std::string* _internal_mutable_syntax();
   public:
 
+  // optional string edition = 13;
+  bool has_edition() const;
+  private:
+  bool _internal_has_edition() const;
+  public:
+  void clear_edition();
+  const std::string& edition() const;
+  template <typename ArgT0 = const std::string&, typename... ArgT>
+  void set_edition(ArgT0&& arg0, ArgT... args);
+  std::string* mutable_edition();
+  PROTOBUF_NODISCARD std::string* release_edition();
+  void set_allocated_edition(std::string* edition);
+  private:
+  const std::string& _internal_edition() const;
+  inline PROTOBUF_ALWAYS_INLINE void _internal_set_edition(const std::string& value);
+  std::string* _internal_mutable_edition();
+  public:
+
   // optional .google.protobuf.FileOptions options = 8;
   bool has_options() const;
   private:
@@ -875,6 +894,7 @@ class PROTOBUF_EXPORT FileDescriptorProto final :
     ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr name_;
     ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr package_;
     ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr syntax_;
+    ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr edition_;
     ::PROTOBUF_NAMESPACE_ID::FileOptions* options_;
     ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo* source_code_info_;
   };
@@ -9042,7 +9062,7 @@ FileDescriptorProto::extension() const {
 
 // optional .google.protobuf.FileOptions options = 8;
 inline bool FileDescriptorProto::_internal_has_options() const {
-  bool value = (_impl_._has_bits_[0] & 0x00000008u) != 0;
+  bool value = (_impl_._has_bits_[0] & 0x00000010u) != 0;
   PROTOBUF_ASSUME(!value || _impl_.options_ != nullptr);
   return value;
 }
@@ -9051,7 +9071,7 @@ inline bool FileDescriptorProto::has_options() const {
 }
 inline void FileDescriptorProto::clear_options() {
   if (_impl_.options_ != nullptr) _impl_.options_->Clear();
-  _impl_._has_bits_[0] &= ~0x00000008u;
+  _impl_._has_bits_[0] &= ~0x00000010u;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::FileOptions& FileDescriptorProto::_internal_options() const {
   const ::PROTOBUF_NAMESPACE_ID::FileOptions* p = _impl_.options_;
@@ -9069,14 +9089,14 @@ inline void FileDescriptorProto::unsafe_arena_set_allocated_options(
   }
   _impl_.options_ = options;
   if (options) {
-    _impl_._has_bits_[0] |= 0x00000008u;
+    _impl_._has_bits_[0] |= 0x00000010u;
   } else {
-    _impl_._has_bits_[0] &= ~0x00000008u;
+    _impl_._has_bits_[0] &= ~0x00000010u;
   }
   // @@protoc_insertion_point(field_unsafe_arena_set_allocated:google.protobuf.FileDescriptorProto.options)
 }
 inline ::PROTOBUF_NAMESPACE_ID::FileOptions* FileDescriptorProto::release_options() {
-  _impl_._has_bits_[0] &= ~0x00000008u;
+  _impl_._has_bits_[0] &= ~0x00000010u;
   ::PROTOBUF_NAMESPACE_ID::FileOptions* temp = _impl_.options_;
   _impl_.options_ = nullptr;
 #ifdef PROTOBUF_FORCE_COPY_IN_RELEASE
@@ -9092,13 +9112,13 @@ inline ::PROTOBUF_NAMESPACE_ID::FileOptions* FileDescriptorProto::release_option
 }
 inline ::PROTOBUF_NAMESPACE_ID::FileOptions* FileDescriptorProto::unsafe_arena_release_options() {
   // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.options)
-  _impl_._has_bits_[0] &= ~0x00000008u;
+  _impl_._has_bits_[0] &= ~0x00000010u;
   ::PROTOBUF_NAMESPACE_ID::FileOptions* temp = _impl_.options_;
   _impl_.options_ = nullptr;
   return temp;
 }
 inline ::PROTOBUF_NAMESPACE_ID::FileOptions* FileDescriptorProto::_internal_mutable_options() {
-  _impl_._has_bits_[0] |= 0x00000008u;
+  _impl_._has_bits_[0] |= 0x00000010u;
   if (_impl_.options_ == nullptr) {
     auto* p = CreateMaybeMessage<::PROTOBUF_NAMESPACE_ID::FileOptions>(GetArenaForAllocation());
     _impl_.options_ = p;
@@ -9122,9 +9142,9 @@ inline void FileDescriptorProto::set_allocated_options(::PROTOBUF_NAMESPACE_ID::
       options = ::PROTOBUF_NAMESPACE_ID::internal::GetOwnedMessage(
           message_arena, options, submessage_arena);
     }
-    _impl_._has_bits_[0] |= 0x00000008u;
+    _impl_._has_bits_[0] |= 0x00000010u;
   } else {
-    _impl_._has_bits_[0] &= ~0x00000008u;
+    _impl_._has_bits_[0] &= ~0x00000010u;
   }
   _impl_.options_ = options;
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.FileDescriptorProto.options)
@@ -9132,7 +9152,7 @@ inline void FileDescriptorProto::set_allocated_options(::PROTOBUF_NAMESPACE_ID::
 
 // optional .google.protobuf.SourceCodeInfo source_code_info = 9;
 inline bool FileDescriptorProto::_internal_has_source_code_info() const {
-  bool value = (_impl_._has_bits_[0] & 0x00000010u) != 0;
+  bool value = (_impl_._has_bits_[0] & 0x00000020u) != 0;
   PROTOBUF_ASSUME(!value || _impl_.source_code_info_ != nullptr);
   return value;
 }
@@ -9141,7 +9161,7 @@ inline bool FileDescriptorProto::has_source_code_info() const {
 }
 inline void FileDescriptorProto::clear_source_code_info() {
   if (_impl_.source_code_info_ != nullptr) _impl_.source_code_info_->Clear();
-  _impl_._has_bits_[0] &= ~0x00000010u;
+  _impl_._has_bits_[0] &= ~0x00000020u;
 }
 inline const ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo& FileDescriptorProto::_internal_source_code_info() const {
   const ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo* p = _impl_.source_code_info_;
@@ -9159,14 +9179,14 @@ inline void FileDescriptorProto::unsafe_arena_set_allocated_source_code_info(
   }
   _impl_.source_code_info_ = source_code_info;
   if (source_code_info) {
-    _impl_._has_bits_[0] |= 0x00000010u;
+    _impl_._has_bits_[0] |= 0x00000020u;
   } else {
-    _impl_._has_bits_[0] &= ~0x00000010u;
+    _impl_._has_bits_[0] &= ~0x00000020u;
   }
   // @@protoc_insertion_point(field_unsafe_arena_set_allocated:google.protobuf.FileDescriptorProto.source_code_info)
 }
 inline ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo* FileDescriptorProto::release_source_code_info() {
-  _impl_._has_bits_[0] &= ~0x00000010u;
+  _impl_._has_bits_[0] &= ~0x00000020u;
   ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo* temp = _impl_.source_code_info_;
   _impl_.source_code_info_ = nullptr;
 #ifdef PROTOBUF_FORCE_COPY_IN_RELEASE
@@ -9182,13 +9202,13 @@ inline ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo* FileDescriptorProto::release_sou
 }
 inline ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo* FileDescriptorProto::unsafe_arena_release_source_code_info() {
   // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.source_code_info)
-  _impl_._has_bits_[0] &= ~0x00000010u;
+  _impl_._has_bits_[0] &= ~0x00000020u;
   ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo* temp = _impl_.source_code_info_;
   _impl_.source_code_info_ = nullptr;
   return temp;
 }
 inline ::PROTOBUF_NAMESPACE_ID::SourceCodeInfo* FileDescriptorProto::_internal_mutable_source_code_info() {
-  _impl_._has_bits_[0] |= 0x00000010u;
+  _impl_._has_bits_[0] |= 0x00000020u;
   if (_impl_.source_code_info_ == nullptr) {
     auto* p = CreateMaybeMessage<::PROTOBUF_NAMESPACE_ID::SourceCodeInfo>(GetArenaForAllocation());
     _impl_.source_code_info_ = p;
@@ -9212,9 +9232,9 @@ inline void FileDescriptorProto::set_allocated_source_code_info(::PROTOBUF_NAMES
       source_code_info = ::PROTOBUF_NAMESPACE_ID::internal::GetOwnedMessage(
           message_arena, source_code_info, submessage_arena);
     }
-    _impl_._has_bits_[0] |= 0x00000010u;
+    _impl_._has_bits_[0] |= 0x00000020u;
   } else {
-    _impl_._has_bits_[0] &= ~0x00000010u;
+    _impl_._has_bits_[0] &= ~0x00000020u;
   }
   _impl_.source_code_info_ = source_code_info;
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.FileDescriptorProto.source_code_info)
@@ -9286,6 +9306,72 @@ inline void FileDescriptorProto::set_allocated_syntax(std::string* syntax) {
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.FileDescriptorProto.syntax)
 }
 
+// optional string edition = 13;
+inline bool FileDescriptorProto::_internal_has_edition() const {
+  bool value = (_impl_._has_bits_[0] & 0x00000008u) != 0;
+  return value;
+}
+inline bool FileDescriptorProto::has_edition() const {
+  return _internal_has_edition();
+}
+inline void FileDescriptorProto::clear_edition() {
+  _impl_.edition_.ClearToEmpty();
+  _impl_._has_bits_[0] &= ~0x00000008u;
+}
+inline const std::string& FileDescriptorProto::edition() const {
+  // @@protoc_insertion_point(field_get:google.protobuf.FileDescriptorProto.edition)
+  return _internal_edition();
+}
+template <typename ArgT0, typename... ArgT>
+inline PROTOBUF_ALWAYS_INLINE
+void FileDescriptorProto::set_edition(ArgT0&& arg0, ArgT... args) {
+ _impl_._has_bits_[0] |= 0x00000008u;
+ _impl_.edition_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+  // @@protoc_insertion_point(field_set:google.protobuf.FileDescriptorProto.edition)
+}
+inline std::string* FileDescriptorProto::mutable_edition() {
+  std::string* _s = _internal_mutable_edition();
+  // @@protoc_insertion_point(field_mutable:google.protobuf.FileDescriptorProto.edition)
+  return _s;
+}
+inline const std::string& FileDescriptorProto::_internal_edition() const {
+  return _impl_.edition_.Get();
+}
+inline void FileDescriptorProto::_internal_set_edition(const std::string& value) {
+  _impl_._has_bits_[0] |= 0x00000008u;
+  _impl_.edition_.Set(value, GetArenaForAllocation());
+}
+inline std::string* FileDescriptorProto::_internal_mutable_edition() {
+  _impl_._has_bits_[0] |= 0x00000008u;
+  return _impl_.edition_.Mutable(GetArenaForAllocation());
+}
+inline std::string* FileDescriptorProto::release_edition() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.edition)
+  if (!_internal_has_edition()) {
+    return nullptr;
+  }
+  _impl_._has_bits_[0] &= ~0x00000008u;
+  auto* p = _impl_.edition_.Release();
+#ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
+  _impl_.edition_.Set("", GetArenaForAllocation());
+#endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
+  return p;
+}
+inline void FileDescriptorProto::set_allocated_edition(std::string* edition) {
+  if (edition != nullptr) {
+    _impl_._has_bits_[0] |= 0x00000008u;
+  } else {
+    _impl_._has_bits_[0] &= ~0x00000008u;
+  }
+  _impl_.edition_.SetAllocated(edition, GetArenaForAllocation());
+#ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
+  if (_impl_.edition_.IsDefault()) {
+    _impl_.edition_.Set("", GetArenaForAllocation());
+  }
+#endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
+  // @@protoc_insertion_point(field_set_allocated:google.protobuf.FileDescriptorProto.edition)
+}
+
 // -------------------------------------------------------------------
 
 // DescriptorProto_ExtensionRange
diff --git a/src/google/protobuf/descriptor.proto b/src/google/protobuf/descriptor.proto
index 5b4d06b41c..5404b14190 100644
--- a/src/google/protobuf/descriptor.proto
+++ b/src/google/protobuf/descriptor.proto
@@ -86,8 +86,13 @@ message FileDescriptorProto {
   optional SourceCodeInfo source_code_info = 9;
 
   // The syntax of the proto file.
-  // The supported values are "proto2" and "proto3".
+  // The supported values are "proto2", "proto3", and "editions".
+  //
+  // If `edition` is present, this value must be "editions".
   optional string syntax = 12;
+
+  // The edition of the proto file, which is an opaque string.
+  optional string edition = 13;
 }
 
 // Describes a message type.
diff --git a/src/google/protobuf/generated_message_reflection.cc b/src/google/protobuf/generated_message_reflection.cc
index aefec99081..7d19cf5d52 100644
--- a/src/google/protobuf/generated_message_reflection.cc
+++ b/src/google/protobuf/generated_message_reflection.cc
@@ -395,7 +395,19 @@ size_t Reflection::SpaceUsedLong(const Message& message) const {
       }
     }
   }
+#ifndef PROTOBUF_FUZZ_MESSAGE_SPACE_USED_LONG
   return total_size;
+#else
+  // Use both `this` and `dummy` to generate the seed so that the scale factor
+  // is both per-object and non-predictable, but consistent across multiple
+  // calls in the same binary.
+  static bool dummy;
+  uintptr_t seed =
+      reinterpret_cast<uintptr_t>(&dummy) ^ reinterpret_cast<uintptr_t>(this);
+  // Fuzz the size by +/- 50%.
+  double scale = (static_cast<double>(seed % 10000) / 10000) + 0.5;
+  return total_size * scale;
+#endif
 }
 
 namespace {
diff --git a/src/google/protobuf/message.h b/src/google/protobuf/message.h
index 82873885bb..d098c81d79 100644
--- a/src/google/protobuf/message.h
+++ b/src/google/protobuf/message.h
@@ -298,6 +298,10 @@ class PROTOBUF_EXPORT Message : public MessageLite {
   // using reflection (rather than the generated code implementation for
   // ByteSize()). Like ByteSize(), its CPU time is linear in the number of
   // fields defined for the proto.
+  //
+  // Note: The precise value of this method should never be depended on, and can
+  // change substantially due to internal details.  In debug builds, this will
+  // include a random fuzz factor to prevent these dependencies.
   virtual size_t SpaceUsedLong() const;
 
   PROTOBUF_DEPRECATED_MSG("Please use SpaceUsedLong() instead")
diff --git a/src/google/protobuf/port_def.inc b/src/google/protobuf/port_def.inc
index 1da0410fb9..ba71a9fb45 100644
--- a/src/google/protobuf/port_def.inc
+++ b/src/google/protobuf/port_def.inc
@@ -532,6 +532,10 @@
 #error PROTOBUF_FORCE_RESET_IN_CLEAR was previously defined
 #endif
 
+#ifdef PROTOBUF_FUZZ_MESSAGE_SPACE_USED_LONG
+#error PROTOBUF_FUZZ_MESSAGE_SPACE_USED_LONG was previously defined
+#endif
+
 // Force copy the default string to a string field so that non-optimized builds
 // have harder-to-rely-on address stability.
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
diff --git a/src/google/protobuf/port_undef.inc b/src/google/protobuf/port_undef.inc
index 184980a7e9..4473bdafa4 100644
--- a/src/google/protobuf/port_undef.inc
+++ b/src/google/protobuf/port_undef.inc
@@ -73,6 +73,7 @@
 #undef PROTOBUF_FORCE_COPY_IN_SWAP
 #undef PROTOBUF_FORCE_COPY_IN_MOVE
 #undef PROTOBUF_FORCE_RESET_IN_CLEAR
+#undef PROTOBUF_FUZZ_MESSAGE_SPACE_USED_LONG
 #undef PROTOBUF_FORCE_COPY_DEFAULT_STRING
 #undef PROTOBUF_NAMESPACE_OPEN
 #undef PROTOBUF_NAMESPACE_CLOSE
diff --git a/src/google/protobuf/stubs/strutil.cc b/src/google/protobuf/stubs/strutil.cc
index 8e9b398360..d452f6e72b 100644
--- a/src/google/protobuf/stubs/strutil.cc
+++ b/src/google/protobuf/stubs/strutil.cc
@@ -503,10 +503,9 @@ int CEscapeInternal(const char* src, int src_len, char* dest,
              (last_hex_escape && isxdigit(*src)))) {
           // need space for 4 letter escape and the trailing '\0' to
           // be written by snprintf.
-          if (dest_len - used < 5)
-            return -1;
+          if (dest_len - used < 5) return -1;
           snprintf(dest + used, 5, (use_hex ? "\\x%02x" : "\\%03o"),
-                  static_cast<uint8_t>(*src));
+                   static_cast<uint8_t>(*src));
           is_hex_escape = use_hex;
           used += 4;
         } else {
diff --git a/src/google/protobuf/util/json_util.cc b/src/google/protobuf/util/json_util.cc
index c39c10d87b..c15f3f10ae 100644
--- a/src/google/protobuf/util/json_util.cc
+++ b/src/google/protobuf/util/json_util.cc
@@ -45,6 +45,7 @@
 #include <google/protobuf/util/internal/protostream_objectwriter.h>
 #include <google/protobuf/util/type_resolver.h>
 #include <google/protobuf/util/type_resolver_util.h>
+#include <google/protobuf/util/zero_copy_sink.h>
 #include <google/protobuf/stubs/status_macros.h>
 
 // clang-format off
@@ -54,35 +55,7 @@
 namespace google {
 namespace protobuf {
 namespace util {
-
-namespace internal {
-ZeroCopyStreamByteSink::~ZeroCopyStreamByteSink() {
-  if (buffer_size_ > 0) {
-    stream_->BackUp(buffer_size_);
-  }
-}
-
-void ZeroCopyStreamByteSink::Append(const char* bytes, size_t len) {
-  while (true) {
-    if (len <= buffer_size_) {  // NOLINT
-      memcpy(buffer_, bytes, len);
-      buffer_ = static_cast<char*>(buffer_) + len;
-      buffer_size_ -= len;
-      return;
-    }
-    if (buffer_size_ > 0) {
-      memcpy(buffer_, bytes, buffer_size_);
-      bytes += buffer_size_;
-      len -= buffer_size_;
-    }
-    if (!stream_->Next(&buffer_, &buffer_size_)) {
-      // There isn't a way for ByteSink to report errors.
-      buffer_size_ = 0;
-      return;
-    }
-  }
-}
-}  // namespace internal
+using ::google::protobuf::util::zc_sink_internal::ZeroCopyStreamByteSink;
 
 util::Status BinaryToJsonStream(TypeResolver* resolver,
                                 const std::string& type_url,
@@ -181,7 +154,7 @@ util::Status JsonToBinaryStream(TypeResolver* resolver,
                                 const JsonParseOptions& options) {
   google::protobuf::Type type;
   RETURN_IF_ERROR(resolver->ResolveMessageType(type_url, &type));
-  internal::ZeroCopyStreamByteSink sink(binary_output);
+  ZeroCopyStreamByteSink sink(binary_output);
   StatusErrorListener listener;
   converter::ProtoStreamObjectWriter::Options proto_writer_options;
   proto_writer_options.ignore_unknown_fields = options.ignore_unknown_fields;
diff --git a/src/google/protobuf/util/json_util.h b/src/google/protobuf/util/json_util.h
index 0f1c4d8b5f..4f4594e2f9 100644
--- a/src/google/protobuf/util/json_util.h
+++ b/src/google/protobuf/util/json_util.h
@@ -175,26 +175,6 @@ inline util::Status JsonToBinaryString(TypeResolver* resolver,
   return JsonToBinaryString(resolver, type_url, json_input, binary_output,
                             JsonParseOptions());
 }
-
-namespace internal {
-// Internal helper class. Put in the header so we can write unit-tests for it.
-class PROTOBUF_EXPORT ZeroCopyStreamByteSink : public strings::ByteSink {
- public:
-  explicit ZeroCopyStreamByteSink(io::ZeroCopyOutputStream* stream)
-      : stream_(stream), buffer_(nullptr), buffer_size_(0) {}
-  ~ZeroCopyStreamByteSink() override;
-
-  void Append(const char* bytes, size_t len) override;
-
- private:
-  io::ZeroCopyOutputStream* stream_;
-  void* buffer_;
-  int buffer_size_;
-
-  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ZeroCopyStreamByteSink);
-};
-}  // namespace internal
-
 }  // namespace util
 }  // namespace protobuf
 }  // namespace google
diff --git a/src/google/protobuf/util/json_util_test.cc b/src/google/protobuf/util/json_util_test.cc
index 29ffe865d9..10494e55a7 100644
--- a/src/google/protobuf/util/json_util_test.cc
+++ b/src/google/protobuf/util/json_util_test.cc
@@ -632,139 +632,6 @@ TEST(JsonUtilTest, TestParsingEnumIgnoreCase) {
   ASSERT_EQ(m.enum_value(), proto3::BAR);
 }
 
-// A ZeroCopyOutputStream that writes to multiple buffers.
-class SegmentedZeroCopyOutputStream : public io::ZeroCopyOutputStream {
- public:
-  explicit SegmentedZeroCopyOutputStream(
-      std::vector<StringPiece> segments)
-      : segments_(segments) {
-    // absl::c_* functions are not cloned in OSS.
-    std::reverse(segments_.begin(), segments_.end());
-  }
-
-  bool Next(void** buffer, int* length) override {
-    if (segments_.empty()) {
-      return false;
-    }
-    last_segment_ = segments_.back();
-    segments_.pop_back();
-    // TODO(b/234159981): This is only ever constructed in test code, and only
-    // from non-const bytes, so this is a valid cast. We need to do this since
-    // OSS proto does not yet have absl::Span; once we take a full Abseil
-    // dependency we should use that here instead.
-    *buffer = const_cast<char*>(last_segment_.data());
-    *length = static_cast<int>(last_segment_.size());
-    byte_count_ += static_cast<int64_t>(last_segment_.size());
-    return true;
-  }
-
-  void BackUp(int length) override {
-    GOOGLE_CHECK(length <= static_cast<int>(last_segment_.size()));
-
-    size_t backup = last_segment_.size() - static_cast<size_t>(length);
-    segments_.push_back(last_segment_.substr(backup));
-    last_segment_ = last_segment_.substr(0, backup);
-    byte_count_ -= static_cast<int64_t>(length);
-  }
-
-  int64_t ByteCount() const override { return byte_count_; }
-
- private:
-  std::vector<StringPiece> segments_;
-  StringPiece last_segment_;
-  int64_t byte_count_ = 0;
-};
-
-// This test splits the output buffer and also the input data into multiple
-// segments and checks that the implementation of ZeroCopyStreamByteSink
-// handles all possible cases correctly.
-TEST(ZeroCopyStreamByteSinkTest, TestAllInputOutputPatterns) {
-  static constexpr int kOutputBufferLength = 10;
-  // An exhaustive test takes too long, skip some combinations to make the test
-  // run faster.
-  static constexpr int kSkippedPatternCount = 7;
-
-  char buffer[kOutputBufferLength];
-  for (int split_pattern = 0; split_pattern < (1 << (kOutputBufferLength - 1));
-       split_pattern += kSkippedPatternCount) {
-    // Split the buffer into small segments according to the split_pattern.
-    std::vector<StringPiece> segments;
-    int segment_start = 0;
-    for (int i = 0; i < kOutputBufferLength - 1; ++i) {
-      if (split_pattern & (1 << i)) {
-        segments.push_back(
-            StringPiece(buffer + segment_start, i - segment_start + 1));
-        segment_start = i + 1;
-      }
-    }
-    segments.push_back(StringPiece(buffer + segment_start,
-                                         kOutputBufferLength - segment_start));
-
-    // Write exactly 10 bytes through the ByteSink.
-    std::string input_data = "0123456789";
-    for (int input_pattern = 0; input_pattern < (1 << (input_data.size() - 1));
-         input_pattern += kSkippedPatternCount) {
-      memset(buffer, 0, sizeof(buffer));
-      {
-        SegmentedZeroCopyOutputStream output_stream(segments);
-        internal::ZeroCopyStreamByteSink byte_sink(&output_stream);
-        int start = 0;
-        for (int j = 0; j < input_data.length() - 1; ++j) {
-          if (input_pattern & (1 << j)) {
-            byte_sink.Append(&input_data[start], j - start + 1);
-            start = j + 1;
-          }
-        }
-        byte_sink.Append(&input_data[start], input_data.length() - start);
-      }
-      EXPECT_EQ(std::string(buffer, input_data.length()), input_data);
-    }
-
-    // Write only 9 bytes through the ByteSink.
-    input_data = "012345678";
-    for (int input_pattern = 0; input_pattern < (1 << (input_data.size() - 1));
-         input_pattern += kSkippedPatternCount) {
-      memset(buffer, 0, sizeof(buffer));
-      {
-        SegmentedZeroCopyOutputStream output_stream(segments);
-        internal::ZeroCopyStreamByteSink byte_sink(&output_stream);
-        int start = 0;
-        for (int j = 0; j < input_data.length() - 1; ++j) {
-          if (input_pattern & (1 << j)) {
-            byte_sink.Append(&input_data[start], j - start + 1);
-            start = j + 1;
-          }
-        }
-        byte_sink.Append(&input_data[start], input_data.length() - start);
-      }
-      EXPECT_EQ(std::string(buffer, input_data.length()), input_data);
-      EXPECT_EQ(buffer[input_data.length()], 0);
-    }
-
-    // Write 11 bytes through the ByteSink. The extra byte will just
-    // be ignored.
-    input_data = "0123456789A";
-    for (int input_pattern = 0; input_pattern < (1 << (input_data.size() - 1));
-         input_pattern += kSkippedPatternCount) {
-      memset(buffer, 0, sizeof(buffer));
-      {
-        SegmentedZeroCopyOutputStream output_stream(segments);
-        internal::ZeroCopyStreamByteSink byte_sink(&output_stream);
-        int start = 0;
-        for (int j = 0; j < input_data.length() - 1; ++j) {
-          if (input_pattern & (1 << j)) {
-            byte_sink.Append(&input_data[start], j - start + 1);
-            start = j + 1;
-          }
-        }
-        byte_sink.Append(&input_data[start], input_data.length() - start);
-      }
-      EXPECT_EQ(input_data.substr(0, kOutputBufferLength),
-                std::string(buffer, kOutputBufferLength));
-    }
-  }
-}
-
 TEST(JsonUtilTest, TestWrongJsonInput) {
   StringPiece json = "{\"unknown_field\":\"some_value\"}";
   io::ArrayInputStream input_stream(json.data(), json.size());
diff --git a/src/google/protobuf/util/zero_copy_sink.cc b/src/google/protobuf/util/zero_copy_sink.cc
new file mode 100644
index 0000000000..2b24f11238
--- /dev/null
+++ b/src/google/protobuf/util/zero_copy_sink.cc
@@ -0,0 +1,60 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <google/protobuf/util/zero_copy_sink.h>
+
+namespace google {
+namespace protobuf {
+namespace util {
+namespace zc_sink_internal {
+void ZeroCopyStreamByteSink::Append(const char* bytes, size_t len) {
+  while (true) {
+    if (len <= buffer_size_) {  // NOLINT
+      memcpy(buffer_, bytes, len);
+      buffer_ = static_cast<char*>(buffer_) + len;
+      buffer_size_ -= len;
+      return;
+    }
+    if (buffer_size_ > 0) {
+      memcpy(buffer_, bytes, buffer_size_);
+      bytes += buffer_size_;
+      len -= buffer_size_;
+    }
+    if (!stream_->Next(&buffer_, &buffer_size_)) {
+      // There isn't a way for ByteSink to report errors.
+      buffer_size_ = 0;
+      return;
+    }
+  }
+}
+}  // namespace zc_sink_internal
+}  // namespace util
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/util/zero_copy_sink.h b/src/google/protobuf/util/zero_copy_sink.h
new file mode 100644
index 0000000000..f2fd9d7867
--- /dev/null
+++ b/src/google/protobuf/util/zero_copy_sink.h
@@ -0,0 +1,74 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef GOOGLE_PROTOBUF_UTIL_ZERO_COPY_SINK_H__
+#define GOOGLE_PROTOBUF_UTIL_ZERO_COPY_SINK_H__
+
+#include <cstddef>
+
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/bytestream.h>
+#include <google/protobuf/io/zero_copy_stream.h>
+
+// Must be included last.
+#include <google/protobuf/port_def.inc>
+
+namespace google {
+namespace protobuf {
+namespace util {
+namespace zc_sink_internal {
+// Internal helper class. Put in the header so we can write unit-tests for it.
+class PROTOBUF_EXPORT ZeroCopyStreamByteSink : public strings::ByteSink {
+ public:
+  explicit ZeroCopyStreamByteSink(io::ZeroCopyOutputStream* stream)
+      : stream_(stream) {}
+
+  ~ZeroCopyStreamByteSink() override {
+    if (buffer_size_ > 0) {
+      stream_->BackUp(buffer_size_);
+    }
+  }
+
+  void Append(const char* bytes, size_t len) override;
+
+ private:
+  io::ZeroCopyOutputStream* stream_;
+  void* buffer_ = nullptr;
+  int buffer_size_ = 0;
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ZeroCopyStreamByteSink);
+};
+}  // namespace zc_sink_internal
+}  // namespace util
+}  // namespace protobuf
+}  // namespace google
+
+#include <google/protobuf/port_undef.inc>
+#endif  // GOOGLE_PROTOBUF_UTIL_ZERO_COPY_SINK_H__
diff --git a/src/google/protobuf/util/zero_copy_sink_test.cc b/src/google/protobuf/util/zero_copy_sink_test.cc
new file mode 100644
index 0000000000..9eed0fe160
--- /dev/null
+++ b/src/google/protobuf/util/zero_copy_sink_test.cc
@@ -0,0 +1,226 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <google/protobuf/util/zero_copy_sink.h>
+
+#include <algorithm>
+#include <array>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include <google/protobuf/stubs/logging.h>
+#include <google/protobuf/stubs/common.h>
+#include <gtest/gtest.h>
+#include <google/protobuf/stubs/strutil.h>
+
+namespace google {
+namespace protobuf {
+namespace util {
+namespace zc_sink_internal {
+namespace {
+
+class ChunkedString {
+ public:
+  explicit ChunkedString(StringPiece data, size_t skipped_patterns)
+      : data_(data), skipped_patterns_(skipped_patterns) {}
+
+  // Returns the next chunk; empty if out of chunks.
+  StringPiece NextChunk() {
+    if (pattern_bit_idx_ == data_.size()) {
+      return "";
+    }
+    size_t start = pattern_bit_idx_;
+    do {
+      ++pattern_bit_idx_;
+    } while (pattern_bit_idx_ < data_.size() &&
+             (pattern_ >> pattern_bit_idx_ & 1) == 0);
+    size_t end = pattern_bit_idx_;
+    return data_.substr(start, end - start);
+  }
+
+  // Resets the stream and runs the next pattern of splits.
+  bool NextPattern() {
+    pattern_ += skipped_patterns_;
+    if (pattern_ >= (1 << data_.size())) {
+      return false;
+    }
+    pattern_bit_idx_ = 0;
+    return true;
+  }
+
+  // prints out the pattern as a sequence of quoted strings.
+  std::string PatternAsQuotedString() {
+    std::string out;
+    size_t start = 0;
+    for (size_t i = 0; i <= data_.size(); ++i) {
+      if (i == data_.size() || (pattern_ >> start & 1) != 0) {
+        if (!out.empty()) {
+          StrAppend(&out, " ");
+        }
+        StrAppend(
+            &out, "\"",
+            strings::CHexEscape(std::string{data_.substr(start, i - start)}),
+            "\"");
+        start = i;
+      }
+    }
+    return out;
+  }
+
+ private:
+  StringPiece data_;
+  size_t skipped_patterns_;
+  // pattern_ is a bitset indicating at which indices we insert a seam.
+  uint64_t pattern_ = 0;
+  size_t pattern_bit_idx_ = 0;
+};
+
+class PatternedOutputStream : public io::ZeroCopyOutputStream {
+ public:
+  explicit PatternedOutputStream(ChunkedString data) : data_(data) {}
+
+  bool Next(void** buffer, int* length) override {
+    StringPiece segment;
+    if (!back_up_.empty()) {
+      segment = back_up_.back();
+      back_up_.pop_back();
+    } else {
+      segment_ = data_.NextChunk();
+      segment = segment_;
+    }
+
+    if (segment_.empty()) {
+      return false;
+    }
+
+    // TODO(b/234159981): This is only ever constructed in test code, and only
+    // from non-const bytes, so this is a valid cast. We need to do this since
+    // OSS proto does not yet have absl::Span; once we take a full Abseil
+    // dependency we should use that here instead.
+    *buffer = const_cast<char*>(segment.data());
+    *length = static_cast<int>(segment.size());
+    byte_count_ += static_cast<int64_t>(segment.size());
+    return true;
+  }
+
+  void BackUp(int length) override {
+    GOOGLE_CHECK(length <= static_cast<int>(segment_.size()));
+
+    size_t backup = segment_.size() - static_cast<size_t>(length);
+    back_up_.push_back(segment_.substr(backup));
+    segment_ = segment_.substr(0, backup);
+    byte_count_ -= static_cast<int64_t>(length);
+  }
+
+  int64_t ByteCount() const override { return byte_count_; }
+
+ private:
+  ChunkedString data_;
+  StringPiece segment_;
+
+  std::vector<StringPiece> back_up_;
+  int64_t byte_count_ = 0;
+};
+
+class ZeroCopyStreamByteSinkTest : public testing::Test {
+ protected:
+  std::array<char, 10> output_{};
+  StringPiece output_view_{output_.data(), output_.size()};
+  ChunkedString output_chunks_{output_view_, 7};
+};
+
+TEST_F(ZeroCopyStreamByteSinkTest, WriteExact) {
+  do {
+    SCOPED_TRACE(output_chunks_.PatternAsQuotedString());
+    ChunkedString input("0123456789", 1);
+
+    do {
+      SCOPED_TRACE(input.PatternAsQuotedString());
+      output_ = {};
+      PatternedOutputStream output_stream(output_chunks_);
+      ZeroCopyStreamByteSink byte_sink(&output_stream);
+      SCOPED_TRACE(input.PatternAsQuotedString());
+      StringPiece chunk;
+      while (!(chunk = input.NextChunk()).empty()) {
+        byte_sink.Append(chunk.data(), chunk.size());
+      }
+    } while (input.NextPattern());
+
+    ASSERT_EQ(output_view_, "0123456789");
+  } while (output_chunks_.NextPattern());
+}
+
+TEST_F(ZeroCopyStreamByteSinkTest, WriteShort) {
+  do {
+    SCOPED_TRACE(output_chunks_.PatternAsQuotedString());
+    ChunkedString input("012345678", 1);
+
+    do {
+      SCOPED_TRACE(input.PatternAsQuotedString());
+      output_ = {};
+      PatternedOutputStream output_stream(output_chunks_);
+      ZeroCopyStreamByteSink byte_sink(&output_stream);
+      SCOPED_TRACE(input.PatternAsQuotedString());
+      StringPiece chunk;
+      while (!(chunk = input.NextChunk()).empty()) {
+        byte_sink.Append(chunk.data(), chunk.size());
+      }
+    } while (input.NextPattern());
+
+    ASSERT_EQ(output_view_, StringPiece("012345678\0", 10));
+  } while (output_chunks_.NextPattern());
+}
+
+TEST_F(ZeroCopyStreamByteSinkTest, WriteLong) {
+  do {
+    SCOPED_TRACE(output_chunks_.PatternAsQuotedString());
+    ChunkedString input("0123456789A", 1);
+
+    do {
+      SCOPED_TRACE(input.PatternAsQuotedString());
+      output_ = {};
+      PatternedOutputStream output_stream(output_chunks_);
+      ZeroCopyStreamByteSink byte_sink(&output_stream);
+      SCOPED_TRACE(input.PatternAsQuotedString());
+      StringPiece chunk;
+      while (!(chunk = input.NextChunk()).empty()) {
+        byte_sink.Append(chunk.data(), chunk.size());
+      }
+    } while (input.NextPattern());
+
+    ASSERT_EQ(output_view_, "0123456789");
+  } while (output_chunks_.NextPattern());
+}
+}  // namespace
+}  // namespace zc_sink_internal
+}  // namespace util
+}  // namespace protobuf
+}  // namespace google