Removing _LIBCPP_DISABLE_UNUSED_STRUCT_WARNINGS from libc++ enables

`[[gnu::__warn_unused__]]` on standard library types (such as
`std::string` and `std::set`), surfacing `-Wunused-variable` warnings
in `//third_party/flatbuffers`. See [upstream LLVM commit](https://github.com/llvm/llvm-project/commit/ab8b037ef7b398aa864959a69f328fa69b567f74) for reference.

Remove unreferenced variable declarations across the code generators and
binary annotator whose initializers have no observable side effects.

PiperOrigin-RevId: 999136370

.github/workflows/build.yml

@@ -545,7 +545,7 @@ jobs:
       # FIXME: make test script not rely on flatc
       run: cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DFLATBUFFERS_BUILD_TESTS=OFF -DFLATBUFFERS_INSTALL=OFF -DFLATBUFFERS_BUILD_FLATLIB=OFF -DFLATBUFFERS_BUILD_FLATHASH=OFF . && make -j
     - name: pnpm
-      run: npm install -g pnpm
+      run: npm install -g pnpm@10
     - name: deps
       run: pnpm i
     - name: compile

Package.swift

@@ -75,6 +75,17 @@ extension Array where Element == Package.Dependency {
       .package(
         url: "https://github.com/grpc/grpc-swift-nio-transport.git",
         from: "2.0.0"),
+      // swift-crypto arrives through grpc-swift-nio-transport -> swift-nio-ssl
+      // and is otherwise resolved afresh on every build, because this package
+      // ships no Package.resolved. 5.x asks for swift-tools-version 6.2, so only
+      // the 6.2 CI job selects it - and then fails to compile it, because 5.x
+      // uses `@nonexhaustive`, which the 6.2.x toolchains do not accept yet.
+      // Stay on the last 4.x release that still builds with every toolchain in
+      // the Swift CI matrix (4.3.0 declares swift-tools-version 6.0; 4.4+ asks
+      // for 6.1 and would drop the 6.0 job).
+      .package(
+        url: "https://github.com/apple/swift-crypto.git",
+        "4.0.0" ..< "4.4.0"),
     ]
     #endif
   }

benchmarks/swift/Benchmarks/FlatbuffersBenchmarks/FlatbuffersBenchmarks.swift

@@ -97,6 +97,7 @@ let benchmarks = {
     for _ in benchmark.scaledIterations {
       blackHole(ByteBuffer(assumingMemoryBound: memory, capacity: Int(oneGB)))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Clearing 1GB", configuration: singleConfiguration) { benchmark in
@@ -105,6 +106,7 @@ let benchmarks = {
     for _ in benchmark.scaledIterations {
       blackHole(fb.clear())
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Strings 10") { benchmark in
@@ -113,6 +115,7 @@ let benchmarks = {
     for _ in benchmark.scaledIterations {
       blackHole(fb.create(string: str10))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Strings 100") { benchmark in
@@ -121,6 +124,7 @@ let benchmarks = {
     for _ in benchmark.scaledIterations {
       blackHole(fb.create(string: str100))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Vector 1 Bytes") { benchmark in
@@ -129,6 +133,7 @@ let benchmarks = {
     for _ in benchmark.scaledIterations {
       blackHole(fb.createVector(bytes: bytes))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Vector 1 Ints") { benchmark in
@@ -137,6 +142,7 @@ let benchmarks = {
     for _ in benchmark.scaledIterations {
       blackHole(fb.createVector(ints))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Vector 100 Ints") { benchmark in
@@ -145,6 +151,7 @@ let benchmarks = {
     for i in benchmark.scaledIterations {
       blackHole(fb.createVector(ints))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Vector 100 Bytes") { benchmark in
@@ -153,6 +160,7 @@ let benchmarks = {
     for i in benchmark.scaledIterations {
       blackHole(fb.createVector(bytes))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Vector 100 ContiguousBytes") { benchmark in
@@ -161,6 +169,7 @@ let benchmarks = {
     for i in benchmark.scaledIterations {
       blackHole(fb.createVector(bytes: bytes))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark(
@@ -178,6 +187,7 @@ let benchmarks = {
       fb.add(offset: off, at: 8)
       blackHole(fb.endTable(at: s))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark(
@@ -190,6 +200,7 @@ let benchmarks = {
       let s = fb.startTable(with: 4)
       blackHole(fb.endTable(at: s))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Struct") { benchmark in
@@ -198,6 +209,7 @@ let benchmarks = {
     for _ in benchmark.scaledIterations {
       blackHole(fb.create(struct: array.first!))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Structs") { benchmark in
@@ -219,6 +231,7 @@ let benchmarks = {
     fb.add(offset: vector, at: 4)
     let root = Offset(offset: fb.endTable(at: start))
     blackHole(fb.finish(offset: root))
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Vector of Offsets") { benchmark in
@@ -239,12 +252,15 @@ let benchmarks = {
       fb.add(offset: off, at: 2)
       blackHole(fb.endTable(at: s))
     }
+    benchmark.stopMeasurement()
   }
 
   Benchmark("Reading Doubles") { benchmark in
     let byteBuffer = ByteBuffer(data: data)
+    benchmark.startMeasurement()
     for _ in benchmark.scaledIterations {
       blackHole(byteBuffer.read(def: Double.self, position: 0))
     }
+    benchmark.stopMeasurement()
   }
 }

benchmarks/swift/Benchmarks/FlexBuffersBenchmarks/FlexBuffersBenchmarks.swift

@@ -0,0 +1,174 @@
+/*
+ * Copyright 2024 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import Benchmark
+import FlexBuffers
+import Foundation
+
+let benchmarks = {
+  let data = {
+    var array = [8888.88, 8888.88]
+    var data = Data()
+    array.withUnsafeBytes { ptr in
+      data.append(contentsOf: ptr)
+    }
+    return data
+  }()
+  let ints: [Int32] = Array(repeating: 42, count: 100)
+  let str10 = (0...9).map { _ -> String in "x" }.joined()
+  let str100 = (0...99).map { _ -> String in "x" }.joined()
+
+  // A representative map: 50 keyed scalars, a keyed string and a keyed vector
+  // of 100 scalars. Used for the realistic decode benchmarks.
+  let mapBuffer: ByteBuffer = {
+    var fbx = FlexBuffersWriter(initialSize: 1 << 16)
+    fbx.map {
+      for i in 0..<50 { $0.add(int: i, key: "i\(i)") }
+      $0.add(string: "hello world", key: "s")
+      $0.vector(key: "v") { v in
+        for x in 0..<100 { v.add(int: x) }
+      }
+    }
+    fbx.finish()
+    return fbx.sizedByteBuffer
+  }()
+
+  let metrics: [BenchmarkMetric] = [
+    .cpuTotal,
+    .wallClock,
+    .mallocCountTotal,
+    .releaseCount,
+    .peakMemoryResident,
+  ]
+  let maxIterations = 1_000_000
+  let maxDuration: Duration = .seconds(3)
+  let megaConfiguration: Benchmark.Configuration = .init(
+    metrics: metrics,
+    warmupIterations: 1,
+    scalingFactor: .mega,
+    maxDuration: maxDuration,
+    maxIterations: maxIterations)
+
+  Benchmark.defaultConfiguration = megaConfiguration
+
+  // Decode (read path)
+
+  // Raw scalar read: isolates `read<T: BitwiseCopyable>` and the `let` blob.
+  Benchmark("Reading Doubles") { benchmark in
+    let byteBuffer = ByteBuffer(data: data)
+    benchmark.startMeasurement()
+    for _ in benchmark.scaledIterations {
+      blackHole(byteBuffer.read(def: Double.self, position: 0))
+    }
+    benchmark.stopMeasurement()
+  }
+
+  // Realistic decode: resolve root map and read a keyed scalar.
+  Benchmark("Decode Map Scalar") { benchmark in
+    benchmark.startMeasurement()
+    for _ in benchmark.scaledIterations {
+      let map = try! getRoot(buffer: mapBuffer)!.map!
+      blackHole(map["i25"]?.int)
+    }
+    benchmark.stopMeasurement()
+  }
+
+  // Realistic decode: resolve root map and read a keyed string.
+  Benchmark("Decode Map String") { benchmark in
+    benchmark.startMeasurement()
+    for _ in benchmark.scaledIterations {
+      let map = try! getRoot(buffer: mapBuffer)!.map!
+      blackHole(map["s"]?.string())
+    }
+    benchmark.stopMeasurement()
+  }
+
+  // Realistic decode: resolve a nested vector and sum its scalars.
+  Benchmark("Decode Vector") { benchmark in
+    benchmark.startMeasurement()
+    for _ in benchmark.scaledIterations {
+      let map = try! getRoot(buffer: mapBuffer)!.map!
+      let vector = map["v"]!.vector!
+      var sum: Int64 = 0
+      for i in 0..<vector.count {
+        sum &+= vector[i]?.int ?? 0
+      }
+      blackHole(sum)
+    }
+    benchmark.stopMeasurement()
+  }
+
+  // Encode (write path)
+  // Writers are reused with `reset(keepingCapacity:)` so per-iteration
+  // allocation does not dominate and mask the write-path cost (which is what
+  // the `@exclusivity(unchecked)` storage pointer affects).
+
+  Benchmark("Strings 10") { benchmark in
+    var fbx = FlexBuffersWriter(initialSize: 1 << 20)
+    benchmark.startMeasurement()
+    for _ in benchmark.scaledIterations {
+      fbx.add(string: str10)
+      fbx.finish()
+      blackHole(fbx.sizedByteBuffer)
+      fbx.reset(keepingCapacity: true)
+    }
+    benchmark.stopMeasurement()
+  }
+
+  Benchmark("Strings 100") { benchmark in
+    var fbx = FlexBuffersWriter(initialSize: 1 << 20)
+    benchmark.startMeasurement()
+    for _ in benchmark.scaledIterations {
+      fbx.add(string: str100)
+      fbx.finish()
+      blackHole(fbx.sizedByteBuffer)
+      fbx.reset(keepingCapacity: true)
+    }
+    benchmark.stopMeasurement()
+  }
+
+  Benchmark("Encoding Vector Of Ints") { benchmark in
+    var fbx = FlexBuffersWriter(initialSize: 1 << 20)
+    benchmark.startMeasurement()
+    for _ in benchmark.scaledIterations {
+      fbx.vector {
+        $0.create(vector: ints)
+      }
+      fbx.finish()
+      blackHole(fbx.sizedByteBuffer)
+      fbx.reset(keepingCapacity: true)
+    }
+    benchmark.stopMeasurement()
+  }
+
+  Benchmark("Encoding Map") { benchmark in
+    var fbx = FlexBuffersWriter(initialSize: 1 << 20)
+    benchmark.startMeasurement()
+    for _ in benchmark.scaledIterations {
+      fbx.map {
+        for i in 0..<50 { $0.add(int: i, key: "i\(i)") }
+        $0.add(string: "hello world", key: "s")
+        $0.vector(key: "v") { v in
+          for x in 0..<100 { v.add(int: x) }
+        }
+      }
+      fbx.finish()
+      blackHole(fbx.sizedByteBuffer)
+      fbx.reset(keepingCapacity: true)
+    }
+    benchmark.stopMeasurement()
+  }
+}

benchmarks/swift/Package.swift

@@ -39,4 +39,14 @@ let package = Package(
       plugins: [
         .plugin(name: "BenchmarkPlugin", package: "package-benchmark"),
       ]),
+    .executableTarget(
+      name: "FlexBuffersBenchmarks",
+      dependencies: [
+        .product(name: "FlexBuffers", package: "flatbuffers"),
+        .product(name: "Benchmark", package: "package-benchmark"),
+      ],
+      path: "Benchmarks/FlexBuffersBenchmarks",
+      plugins: [
+        .plugin(name: "BenchmarkPlugin", package: "package-benchmark"),
+      ]),
   ])

grpc/src/compiler/ts_generator.cc

@@ -504,7 +504,6 @@ grpc::string GenerateInterface(grpc_generator::File* file,
                                const grpc::string& filename) {
   grpc::string output;
 
-  std::set<grpc::string> generated_functions;
   std::map<grpc::string, grpc::string> vars;
 
   vars["PATH"] = file->package();

include/flatbuffers/base.h

@@ -271,7 +271,7 @@ namespace flatbuffers {
   #if (defined(_MSC_VER) && _MSC_VER >= 1800) || \
       (defined(__ANDROID__) && defined(__ANDROID_API__) && __ANDROID_API__>= 26) || \
       (defined(_XOPEN_VERSION) && (_XOPEN_VERSION >= 700)) && \
-      !defined(__Fuchsia__)
+      !defined(__Fuchsia__) && (!defined(__linux__) || defined(__GLIBC__))
     #define FLATBUFFERS_LOCALE_INDEPENDENT 1
   #else
     #define FLATBUFFERS_LOCALE_INDEPENDENT 0

lobster/flatbuffers.lobster

@@ -24,15 +24,14 @@ class handle:
 struct offset:
     o:int
 
-enum sizeof:
+let sz_8 = 1
-    sz_8 = 1
+let sz_16 = 2
-    sz_16 = 2
+let sz_32 = 4
-    sz_32 = 4
+let sz_64 = 8
-    sz_64 = 8
+let sz_voffset = 2
-    sz_voffset = 2
+let sz_uoffset = 4
-    sz_uoffset = 4
+let sz_soffset = 4
-    sz_soffset = 4
+let sz_metadata_fields = 2
-    sz_metadata_fields = 2
 
 class builder:
     buf = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

src/binary_annotator.cpp

@@ -722,8 +722,6 @@ void BinaryAnnotator::BuildTable(const uint64_t table_offset,
     BinaryRegionComment offset_field_comment;
     offset_field_comment.type = BinaryRegionCommentType::TableOffsetField;
     offset_field_comment.name = field->name()->c_str();
-    const std::string offset_prefix =
-        "offset to field `" + std::string(field->name()->c_str()) + "`";
 
     // Validate any field that isn't inline (i.e., non-structs).
     if (!IsInlineField(field)) {

src/idl_gen_cpp.cpp

@@ -404,7 +404,7 @@ class CppGenerator : public BaseGenerator {
       code_ += "struct {{STRUCT_NAME}}BinarySchema {";
       code_ += "  static const uint8_t *data() {";
       code_ += "    // Buffer containing the binary schema.";
-      code_ += "    static const uint8_t bfbsData[" +
+      code_ += "    alignas(uint64_t) static const uint8_t bfbsData[" +
                NumToString(parser_.builder_.GetSize()) + "] = {";
       code_ += binary_schema_hex_text;
       code_ += "    };";
@@ -2737,7 +2737,6 @@ class CppGenerator : public BaseGenerator {
     if (!field.IsScalarOptional()) {
       const bool is_scalar = IsScalar(type.base_type);
       std::string accessor;
-      std::string offset_size = "";
       if (is_scalar) {
         accessor = "GetField<";
       } else if (IsStruct(type)) {
@@ -2815,7 +2814,6 @@ class CppGenerator : public BaseGenerator {
 
   void GenTableFieldType(const FieldDef& field) {
     const auto& type = field.value.type;
-    const auto offset_str = GenFieldOffsetName(field);
     if (!field.IsScalarOptional()) {
       std::string afterptr = " *" + NullableExtension();
       code_.SetValue("FIELD_TYPE",

src/idl_gen_dart.cpp

@@ -654,34 +654,15 @@ class DartGenerator : public BaseGenerator {
 
   std::string NamespaceAliasFromUnionType(Namespace* root_namespace,
                                           const Type& type) {
-    const std::vector<std::string> qualified_name_parts =
+    const Namespace& type_namespace = *type.struct_def->defined_namespace;
-        type.struct_def->defined_namespace->components;
+    if (root_namespace->components == type_namespace.components) {
-    if (std::equal(root_namespace->components.begin(),
-                   root_namespace->components.end(),
-                   qualified_name_parts.begin())) {
       return namer_.Type(*type.struct_def);
     }
 
-    std::string ns;
+    const std::string ns = namer_.Namespace(type_namespace);
-
+    return ns.empty()
-    for (auto it = qualified_name_parts.begin();
+               ? namer_.Type(*type.struct_def)
-         it != qualified_name_parts.end(); ++it) {
+               : ImportAliasName(ns) + "." + namer_.Type(*type.struct_def);
-      auto& part = *it;
-
-      for (size_t i = 0; i < part.length(); i++) {
-        if (i && !isdigit(part[i]) && part[i] == CharToUpper(part[i])) {
-          ns += "_";
-          ns += CharToLower(part[i]);
-        } else {
-          ns += CharToLower(part[i]);
-        }
-      }
-      if (it != qualified_name_parts.end() - 1) {
-        ns += "_";
-      }
-    }
-
-    return ns + "." + namer_.Type(*type.struct_def);
   }
 
   void GenImplementationGetters(
@@ -1168,8 +1149,6 @@ static bool GenerateDart(const Parser& parser, const std::string& path,
 
 static std::string DartMakeRule(const Parser& parser, const std::string& path,
                                 const std::string& file_name) {
-  auto filebase =
-      flatbuffers::StripPath(flatbuffers::StripExtension(file_name));
   dart::DartGenerator generator(parser, path, file_name);
   auto make_rule = generator.Filename("") + ": ";
 

src/idl_gen_kotlin.cpp

@@ -966,8 +966,6 @@ class KotlinGenerator : public BaseGenerator {
       auto bbgetter = ByteBufferGetter(field.value.type, "bb");
       auto ucast = CastToUsigned(field);
       auto offset_val = NumToString(field.value.offset);
-      auto offset_prefix =
-          "val o = __offset(" + offset_val + "); return o != 0 ? ";
       auto value_base_type = field.value.type.base_type;
       // Most field accessors need to retrieve and test the field offset
       // first, this is the offset value for that:

src/idl_gen_kotlin_kmp.cpp

@@ -146,7 +146,6 @@ class KotlinKMPGenerator : public BaseGenerator {
 
     std::string code =
         "// " + std::string(FlatBuffersGeneratedWarning()) + "\n\n";
-    auto qualified = ns.GetFullyQualifiedName("");
     std::string namespace_name = namer_.Namespace(ns);
     if (!namespace_name.empty()) {
       code += "package " + namespace_name;
@@ -341,7 +340,6 @@ class KotlinKMPGenerator : public BaseGenerator {
   std::string GenDefaultBufferValue(const FieldDef& field) const {
     auto& value = field.value;
     auto base_type = value.type.base_type;
-    auto field_name = field.name;
     std::string suffix = IsScalar(base_type) ? LiteralSuffix(value.type) : "";
     if (field.IsScalarOptional()) {
       return "null";
@@ -373,7 +371,6 @@ class KotlinKMPGenerator : public BaseGenerator {
   std::string GenDefaultValue(const FieldDef& field) const {
     auto& value = field.value;
     auto base_type = value.type.base_type;
-    auto field_name = field.name;
     std::string suffix = LiteralSuffix(value.type);
     if (field.IsScalarOptional()) {
       return "null";
@@ -1082,8 +1079,6 @@ class KotlinKMPGenerator : public BaseGenerator {
       auto return_type = GetterReturnType(field);
       auto bbgetter = ByteBufferGetter(field.value.type, "bb");
       auto offset_val = NumToString(field.value.offset);
-      auto offset_prefix =
-          "val o = offset(" + offset_val + "); return o != 0 ? ";
       auto value_base_type = field.value.type.base_type;
       // Most field accessors need to retrieve and test the field offset
       // first, this is the offset value for that:

src/idl_gen_python.cpp

@@ -2010,8 +2010,6 @@ class PythonGenerator : public BaseGenerator {
   void InitializeFromPackedBuf(const StructDef& struct_def,
                                std::string* code_ptr) const {
     auto& code = *code_ptr;
-    const auto struct_var = namer_.Variable(struct_def);
-    const auto struct_type = namer_.Type(struct_def);
 
     code += GenIndents(1) + "@classmethod";
     code += GenIndents(1) + "def InitFromPackedBuf(cls, buf, pos=0):";

src/idl_gen_swift.cpp

@@ -787,7 +787,6 @@ class SwiftGenerator : public BaseGenerator {
   }
 
   void GenTableReaderFields(const FieldDef& field) {
-    const auto offset = NumToString(field.value.offset);
     const auto field_field = namer_.Field(field);
     const auto type = GenType(field.value.type);
     code_.SetValue("FIELDVAR", namer_.Variable(field));
@@ -1382,7 +1381,6 @@ class SwiftGenerator : public BaseGenerator {
       const auto& field = **it;
       if (field.deprecated) continue;
 
-      const auto type = GenType(field.value.type);
       code_.SetValue("FIELDVAR", namer_.Variable(field));
       if (IsArray(field.value.type)) {
         code_.SetValue(

src/idl_gen_ts.cpp

@@ -196,7 +196,6 @@ class TsGenerator : public BaseGenerator {
                                 SkipDir::OutputPathAndTrailingPathSeparator);
       symbolic_name = definition.defined_namespace->components.back();
     } else {
-      auto def_mod_name = namer_.File(definition, SkipFile::SuffixAndExtension);
       symbolic_name = file_name_;
       filepath = path_ + symbolic_name + ".ts";
     }
@@ -286,12 +285,10 @@ class TsGenerator : public BaseGenerator {
         auto base_name =
             namer_.Directories(it.second.ns->components, SkipDir::OutputPath) +
             base_file_name;
-        auto ts_file_path = base_name + ".ts";
         auto base_name_rel = std::string("./");
         base_name_rel +=
             namer_.Directories(rel_components, SkipDir::OutputPath);
         base_name_rel += base_file_name;
-        auto ts_file_path_rel = base_name_rel + ".ts";
         auto type_name = def.first;
         auto fully_qualified_type_name =
             it.second.ns->GetFullyQualifiedName(type_name);
@@ -311,7 +308,6 @@ class TsGenerator : public BaseGenerator {
       const auto child_ns_level = it.second.ns->components.size() + 1;
       for (const auto& it2 : ns_defs_) {
         if (it2.second.ns->components.size() != child_ns_level) continue;
-        auto ts_file_path = it2.second.path + ".ts";
         code += "export * as " + it2.second.symbolic_name + " from './";
         int count = it2.second.ns->components.size() > 1 ? 2 : 1;
         std::vector<std::string> rel_path;
@@ -1176,7 +1172,6 @@ class TsGenerator : public BaseGenerator {
     if (union_type.enum_def) {
       const auto& enum_def = *union_type.enum_def;
       const auto enum_type = AddImport(imports, dependent, enum_def).name;
-      const std::string union_accessor = "this." + field_name;
 
       const auto union_has_string = UnionHasStringType(enum_def);
       const auto field_binded_method = "this." + field_name + ".bind(this)";

swift/Sources/Common/Scalar.swift

@@ -28,7 +28,7 @@ public let FileIdLength = 4
 /// Protocol that All Scalars should conform to
 ///
 /// Scalar is used to conform all the numbers that can be represented in a FlatBuffer. It's used to write/read from the buffer.
-public protocol Scalar: Equatable {
+public protocol Scalar: Equatable, BitwiseCopyable {
   associatedtype NumericValue
   var convertedEndian: NumericValue { get }
 }

swift/Sources/FlatBuffers/ByteBuffer.swift

@@ -27,7 +27,7 @@ public struct ByteBuffer: @unchecked Sendable {
   @usableFromInline
   final class Storage {
     @usableFromInline
-    enum Blob {
+    @frozen enum Blob: ~Copyable {
       #if !os(WASI)
       case data(Data)
       case bytes(any ContiguousBytes)
@@ -36,6 +36,40 @@ public struct ByteBuffer: @unchecked Sendable {
       case byteBuffer(_InternalByteBuffer)
       case array([UInt8])
       case pointer(UnsafeMutableRawPointer)
+
+      init(_ other: borrowing Blob) {
+        switch other {
+        #if !os(WASI)
+        case .data(let data):
+          self = .data(data)
+        case .bytes(let contiguousBytes):
+          self = .bytes(contiguousBytes)
+        #endif
+        case .byteBuffer(let internalByteBuffer):
+          self = .byteBuffer(internalByteBuffer)
+        case .array(let array):
+          self = .array(array)
+        case .pointer(let unsafeMutableRawPointer):
+          self = .pointer(unsafeMutableRawPointer)
+        }
+      }
+
+      var description: String {
+        switch self {
+        #if !os(WASI)
+        case .data(let data):
+          "data: \(data)"
+        case .bytes(let contiguousBytes):
+          "bytes: \(contiguousBytes)"
+        #endif
+        case .byteBuffer(let internalByteBuffer):
+          "byteBuffer: \(internalByteBuffer)"
+        case .array(let array):
+          "array: \(array)"
+        case .pointer(let unsafeMutableRawPointer):
+          "pointer: \(unsafeMutableRawPointer)"
+        }
+      }
     }
 
     /// This storage doesn't own the memory, therefore, we won't deallocate on deinit.
@@ -44,7 +78,7 @@ public struct ByteBuffer: @unchecked Sendable {
     private let capacity: Int
     /// Retained blob of data that requires the storage to retain a pointer to.
     @usableFromInline
-    var retainedBlob: Blob
+    let retainedBlob: Blob
 
     @usableFromInline
     init(count: Int) {
@@ -57,9 +91,9 @@ public struct ByteBuffer: @unchecked Sendable {
     }
 
     @usableFromInline
-    init(blob: Blob, capacity count: Int) {
+    init(blob: borrowing Blob, capacity count: Int) {
       capacity = count
-      retainedBlob = blob
+      retainedBlob = .init(blob)
       isOwned = false
     }
 
@@ -150,6 +184,7 @@ public struct ByteBuffer: @unchecked Sendable {
 
     @discardableResult
     @inline(__always)
+    @inlinable
     func readWithUnsafeRawPointer<T>(
       position: Int,
       _ body: (UnsafeRawPointer) throws -> T) rethrows -> T
@@ -278,7 +313,7 @@ public struct ByteBuffer: @unchecked Sendable {
   ///   - removeBytes: Removes a number of bytes from the current size
   @inline(__always)
   init(
-    blob: Storage.Blob,
+    blob: borrowing Storage.Blob,
     count: Int,
     removing removeBytes: Int)
   {
@@ -318,7 +353,8 @@ public struct ByteBuffer: @unchecked Sendable {
   ///   - def: Type of the object
   ///   - position: the index of the object in the buffer
   @inline(__always)
-  public func read<T>(def: T.Type, position: Int) -> T {
+  @inlinable
+  public func read<T: BitwiseCopyable>(def: T.Type, position: Int) -> T {
     _storage.readWithUnsafeRawPointer(position: position) {
       $0.bindMemory(to: T.self, capacity: 1)
         .pointee
@@ -412,7 +448,7 @@ public struct ByteBuffer: @unchecked Sendable {
   /// - Parameter removeBytes: the amount of bytes to remove from the current Size
   @inline(__always)
   public func duplicate(removing removeBytes: Int = 0) -> ByteBuffer {
-    assert(removeBytes > 0, "Can NOT remove negative bytes")
+    assert(removeBytes >= 0, "Can NOT remove negative bytes")
     assert(
       removeBytes < capacity,
       "Can NOT remove more bytes than the ones allocated")
@@ -464,8 +500,9 @@ public struct ByteBuffer: @unchecked Sendable {
 extension ByteBuffer: CustomDebugStringConvertible {
 
   public var debugDescription: String {
-    """
+    let blobDescription = _storage.retainedBlob.description
-    buffer located at: \(_storage.retainedBlob), 
+    return """
+    buffer located at: \(blobDescription), 
     with capacity of \(capacity),
     { writtenSize: \(_readerIndex), readerSize: \(reader), 
     size: \(size) }

swift/Sources/FlatBuffers/FlatBufferBuilder.swift

@@ -47,7 +47,8 @@ public struct FlatBufferBuilder {
   /// A check to see if finish(::) was ever called to retreive data object
   private(set) var finished = false
   /// A check to see if the buffer should serialize Default values
-  private var serializeDefaults: Bool
+  @usableFromInline
+  let serializeDefaults: Bool
 
   /// Current alignment for the buffer
   var _minAlignment: Int = 0 {
@@ -756,6 +757,7 @@ public struct FlatBufferBuilder {
   ///   - offset: ``Offset`` of another object to be written
   ///   - position: The predefined position of the object
   @inline(__always)
+  @inlinable
   mutating public func add(offset: Offset, at position: VOffset) {
     if offset.isEmpty { return }
     add(element: refer(to: offset.o), def: 0, at: position)
@@ -794,6 +796,7 @@ public struct FlatBufferBuilder {
   ///   - def: Default value for that element
   ///   - position: The predefined position of the element
   @inline(__always)
+  @inlinable
   mutating public func add<T: Scalar>(
     element: T,
     def: T,
@@ -813,6 +816,7 @@ public struct FlatBufferBuilder {
   ///   - element: Optional element of type scalar
   ///   - position: The predefined position of the element
   @inline(__always)
+  @inlinable
   mutating public func add<T: Scalar>(element: T?, at position: VOffset) {
     guard let element = element else { return }
     track(offset: push(element: element), at: position)
@@ -825,6 +829,7 @@ public struct FlatBufferBuilder {
   /// - Parameter element: Element to insert
   /// - returns: position of the Element
   @inline(__always)
+  @inlinable
   @discardableResult
   mutating public func push<T: Scalar>(element: T) -> UOffset {
     let size = MemoryLayout<T>.size
@@ -836,7 +841,8 @@ public struct FlatBufferBuilder {
   }
 
   @inline(__always)
-  public func read<T>(def: T.Type, position: Int) -> T {
+  @inlinable
+  public func read<T: BitwiseCopyable>(def: T.Type, position: Int) -> T {
     _bb.read(def: def, position: position)
   }
 }

swift/Sources/FlatBuffers/FlatBufferObject.swift

@@ -18,7 +18,7 @@ import Foundation
 
 /// NativeStruct is a protocol that indicates if the struct is a native `swift` struct
 /// since now we will be serializing native structs into the buffer.
-public protocol NativeStruct {}
+public protocol NativeStruct: BitwiseCopyable {}
 
 public protocol FlatBufferVerifiableNativeStruct: NativeStruct, Verifiable {}
 

swift/Sources/FlatBuffers/Root.swift

@@ -16,6 +16,30 @@
 
 import Foundation
 
+@inline(__always)
+private func verifySizePrefix(
+  byteBuffer: inout ByteBuffer,
+  requireExactSize: Bool,
+  options: VerifierOptions) throws
+{
+  let verifier = try Verifier(buffer: &byteBuffer, options: options)
+  let prefixPosition = byteBuffer.reader
+  let prefix: UOffset = try verifier.getValue(at: prefixPosition)
+  let availableSize = byteBuffer.size &- UOffset(MemoryLayout<UOffset>.size)
+
+  if requireExactSize {
+    guard prefix == availableSize else {
+      throw FlatbuffersErrors.prefixedSizeNotEqualToBufferSize
+    }
+  } else if prefix > availableSize {
+    throw FlatbuffersErrors.outOfBounds(
+      position: UInt(prefixPosition)
+        &+ UInt(MemoryLayout<UOffset>.size)
+        &+ UInt(prefix),
+      end: byteBuffer.capacity)
+  }
+}
+
 /// Takes in a prefixed sized buffer, where the prefixed size would be skipped.
 /// And would verify that the buffer passed is a valid `Flatbuffers` Object.
 /// - Parameters:
@@ -31,6 +55,10 @@ public func getPrefixedSizeCheckedRoot<T: FlatBufferTable & Verifiable>(
   fileId: String? = nil,
   options: VerifierOptions = .init()) throws -> T
 {
+  try verifySizePrefix(
+    byteBuffer: &byteBuffer,
+    requireExactSize: false,
+    options: options)
   byteBuffer.skipPrefix()
   return try getCheckedRoot(
     byteBuffer: &byteBuffer,
@@ -53,10 +81,11 @@ public func getCheckedPrefixedSizeRoot<T: FlatBufferTable & Verifiable>(
   fileId: String? = nil,
   options: VerifierOptions = .init()) throws -> T
 {
-  let prefix = byteBuffer.skipPrefix()
+  try verifySizePrefix(
-  if prefix != byteBuffer.size {
+    byteBuffer: &byteBuffer,
-    throw FlatbuffersErrors.prefixedSizeNotEqualToBufferSize
+    requireExactSize: true,
-  }
+    options: options)
+  byteBuffer.skipPrefix()
   return try getCheckedRoot(
     byteBuffer: &byteBuffer,
     fileId: fileId,
@@ -95,14 +124,15 @@ public func getCheckedRoot<T: FlatBufferTable & Verifiable>(
   options: VerifierOptions = .init()) throws -> T
 {
   var verifier = try Verifier(buffer: &byteBuffer, options: options)
+  let rootPosition = byteBuffer.reader
   if let fileId = fileId {
-    try verifier.verify(id: fileId)
+    try verifier.verify(id: fileId, at: rootPosition)
   }
-  try ForwardOffset<T>.verify(&verifier, at: 0, of: T.self)
+  try ForwardOffset<T>.verify(&verifier, at: rootPosition, of: T.self)
   return T.init(
     byteBuffer,
-    o: Int32(byteBuffer.read(def: UOffset.self, position: byteBuffer.reader))
+    o: Int32(byteBuffer.read(def: UOffset.self, position: rootPosition))
-      &+ Int32(byteBuffer.reader))
+      &+ Int32(rootPosition))
 }
 
 /// Returns a `NON-Checked` flatbuffers object

swift/Sources/FlatBuffers/Table.swift

@@ -82,7 +82,7 @@ public struct Table {
   /// - Parameters:
   ///   - type: Type of Element that needs to be read from the buffer
   ///   - o: Offset of the Element
-  public func readBuffer<T>(of type: T.Type, at o: Int32) -> T {
+  public func readBuffer<T: BitwiseCopyable>(of type: T.Type, at o: Int32) -> T {
     bb.read(def: T.self, position: Int(o &+ position))
   }
 

swift/Sources/FlatBuffers/Verifiable.swift

@@ -56,8 +56,15 @@ extension Verifiable {
     let len: UOffset = try verifier.getValue(at: position)
     let intLen = Int(len)
     let start = Int(clamping: (position &+ MemoryLayout<Int32>.size).magnitude)
+    let byteCount = intLen.multipliedReportingOverflow(
+      by: MemoryLayout<T>.size)
+    guard !byteCount.overflow else {
+      throw FlatbuffersErrors.outOfBounds(
+        position: UInt.max,
+        end: verifier.capacity)
+    }
     try verifier.isAligned(position: start, type: type.self)
-    try verifier.rangeInBuffer(position: start, size: intLen)
+    try verifier.rangeInBuffer(position: start, size: byteCount.partialValue)
     return (start, intLen)
   }
 }

swift/Sources/FlatBuffers/Verifier.swift

@@ -163,7 +163,7 @@ public struct Verifier {
   /// - Parameter position: Current position to be read
   /// - Throws: `inBuffer` errors
   /// - Returns: a value of type `T` usually a `VTable` or a table offset
-  internal func getValue<T>(at position: Int) throws -> T {
+  internal func getValue<T: BitwiseCopyable>(at position: Int) throws -> T {
     try inBuffer(position: position, of: T.self)
     return _buffer.read(def: T.self, position: position)
   }
@@ -215,12 +215,16 @@ public struct Verifier {
   }
 
   @inline(__always)
-  func verify(id: String) throws {
+  func verify(id: String, at position: Int) throws {
     let size = MemoryLayout<Int32>.size
-    guard storage.capacity >= (size &* 2) else {
+    guard
+      position >= 0,
+      position <= storage.capacity,
+      storage.capacity - position >= size &* 2
+    else {
       throw FlatbuffersErrors.bufferDoesntContainID
     }
-    let str = _buffer.readString(at: size, count: size)
+    let str = _buffer.readString(at: position &+ size, count: size)
     if id == str {
       return
     }

swift/Sources/FlatBuffers/_InternalByteBuffer.swift

@@ -30,7 +30,7 @@ struct _InternalByteBuffer {
   @usableFromInline
   final class Storage {
     /// pointer to the start of the buffer object in memory
-    private(set) var memory: UnsafeMutableRawPointer
+    @exclusivity(unchecked) private(set) var memory: UnsafeMutableRawPointer
 
     @usableFromInline
     init(count: Int, alignment: Int) {
@@ -333,6 +333,7 @@ struct _InternalByteBuffer {
 
   @discardableResult
   @inline(__always)
+  @usableFromInline
   func readWithUnsafeRawPointer<T>(
     position: Int,
     _ body: (UnsafeRawPointer) throws -> T) rethrows -> T

swift/Sources/FlexBuffers/ByteBuffer.swift

@@ -27,7 +27,7 @@ public struct ByteBuffer {
   @usableFromInline
   final class Storage {
     @usableFromInline
-    enum Blob {
+    @frozen enum Blob: ~Copyable {
       #if !os(WASI)
       case data(Data)
       case bytes(any ContiguousBytes)
@@ -36,6 +36,23 @@ public struct ByteBuffer {
       case byteBuffer(_InternalByteBuffer)
       case array([UInt8])
       case pointer(UnsafeMutableRawPointer)
+
+      init(_ other: borrowing Blob) {
+        switch other {
+        #if !os(WASI)
+        case .data(let data):
+          self = .data(data)
+        case .bytes(let contiguousBytes):
+          self = .bytes(contiguousBytes)
+        #endif
+        case .byteBuffer(let internalByteBuffer):
+          self = .byteBuffer(internalByteBuffer)
+        case .array(let array):
+          self = .array(array)
+        case .pointer(let unsafeMutableRawPointer):
+          self = .pointer(unsafeMutableRawPointer)
+        }
+      }
     }
 
     /// This storage doesn't own the memory, therefore, we won't deallocate on deinit.
@@ -44,7 +61,7 @@ public struct ByteBuffer {
     private let capacity: Int
     /// Retained blob of data that requires the storage to retain a pointer to.
     @usableFromInline
-    var retainedBlob: Blob
+    let retainedBlob: Blob
 
     @usableFromInline
     init(count: Int) {
@@ -57,9 +74,9 @@ public struct ByteBuffer {
     }
 
     @usableFromInline
-    init(blob: Blob, capacity count: Int) {
+    init(blob: borrowing Blob, capacity count: Int) {
       capacity = count
-      retainedBlob = blob
+      retainedBlob = .init(blob)
       isOwned = false
     }
 
@@ -276,7 +293,7 @@ public struct ByteBuffer {
   ///   - removeBytes: Removes a number of bytes from the current size
   @inline(__always)
   init(
-    blob: Storage.Blob,
+    blob: borrowing Storage.Blob,
     count: Int,
     removing removeBytes: Int)
   {
@@ -316,7 +333,7 @@ public struct ByteBuffer {
   ///   - def: Type of the object
   ///   - position: the index of the object in the buffer
   @inline(__always)
-  public func read<T>(def: T.Type, position: Int) -> T {
+  public func read<T: BitwiseCopyable>(def: T.Type, position: Int) -> T {
     _storage.readWithUnsafeRawPointer(position: position) {
       $0.bindMemory(to: T.self, capacity: 1)
         .pointee
@@ -360,10 +377,10 @@ public struct ByteBuffer {
   @inline(__always)
   func readSizedScalar<
     T: BinaryInteger,
-    T1: BinaryInteger,
+    T1: BinaryInteger & BitwiseCopyable,
-    T2: BinaryInteger,
+    T2: BinaryInteger & BitwiseCopyable,
-    T3: BinaryInteger,
+    T3: BinaryInteger & BitwiseCopyable,
-    T4: BinaryInteger
+    T4: BinaryInteger & BitwiseCopyable
   >(
     def: T.Type,
     t1: T1.Type,

swift/Sources/FlexBuffers/_InternalByteBuffer.swift

@@ -31,7 +31,7 @@ struct _InternalByteBuffer {
   @usableFromInline
   final class Storage {
     /// pointer to the start of the buffer object in memory
-    var memory: UnsafeMutableRawPointer
+    @exclusivity(unchecked) private(set) var memory: UnsafeMutableRawPointer
 
     @usableFromInline
     init(count: Int, alignment: Int) {

tests/monster_test_bfbs_generated.h

@@ -12,7 +12,7 @@ namespace Example {
 struct MonsterBinarySchema {
   static const uint8_t *data() {
     // Buffer containing the binary schema.
-    static const uint8_t bfbsData[14520] = {
+    alignas(uint64_t) static const uint8_t bfbsData[14520] = {
       0x20,0x00,0x00,0x00,0x42,0x46,0x42,0x53,0x00,0x00,0x00,0x00,0x14,0x00,0x20,0x00,0x04,0x00,0x08,0x00,
       0x0C,0x00,0x10,0x00,0x14,0x00,0x18,0x00,0x00,0x00,0x1C,0x00,0x14,0x00,0x00,0x00,0x58,0x00,0x00,0x00,
       0x34,0x00,0x00,0x00,0x24,0x00,0x00,0x00,0x18,0x00,0x00,0x00,0x70,0x0D,0x00,0x00,0x08,0x00,0x00,0x00,

tests/swift/Tests/Flatbuffers/FlatbuffersVerifierTests.swift

@@ -373,6 +373,58 @@ final class FlatbuffersVerifierTests {
     }
   }
 
+  @Test
+  func testSizePrefixedVerifierUsesPostPrefixRoot() throws {
+    // The size prefix points to a valid empty decoy table at byte 44. The real
+    // root at byte 4 points to a truncated UInt64 vector that must be rejected.
+    let bytes: [UInt8] = [
+      44, 0, 0, 0,
+      16, 0, 0, 0,
+      6, 0, 8, 0, 4, 0,
+      0, 0, 0, 0, 0, 0,
+      12, 0, 0, 0,
+      8, 0, 0, 0, 0, 0, 0, 0,
+      2, 0, 0, 0, 65, 66,
+      0, 0,
+      4, 0, 4, 0,
+      4, 0, 0, 0,
+    ]
+
+    var strictBuffer = ByteBuffer(bytes: bytes)
+    #expect(throws: FlatbuffersErrors.self) {
+      try getCheckedPrefixedSizeRoot(
+        byteBuffer: &strictBuffer) as Swift_Tests_Vectors
+    }
+
+    var prefixedBuffer = ByteBuffer(bytes: bytes)
+    #expect(throws: FlatbuffersErrors.self) {
+      try getPrefixedSizeCheckedRoot(
+        byteBuffer: &prefixedBuffer) as Swift_Tests_Vectors
+    }
+
+    var builder = FlatBufferBuilder()
+    let movie = Movie.createMovie(&builder)
+    Movie.finish(&builder, end: movie, prefix: true)
+    var validBuffer = builder.sizedBuffer
+    let _: Movie = try getCheckedPrefixedSizeRoot(
+      byteBuffer: &validBuffer,
+      fileId: Movie.id)
+
+    var shortBuffer = ByteBuffer(bytes: [0, 0, 0, 0])
+    #expect(throws: FlatbuffersErrors.bufferDoesntContainID) {
+      try getCheckedRoot(
+        byteBuffer: &shortBuffer,
+        fileId: Movie.id) as Movie
+    }
+
+    var oversizedPrefix = ByteBuffer(bytes: [5, 0, 0, 0, 0, 0, 0, 0])
+    #expect(throws: FlatbuffersErrors.outOfBounds(position: 9, end: 8)) {
+      try getPrefixedSizeCheckedRoot(
+        byteBuffer: &oversizedPrefix) as Movie
+    }
+    #expect(oversizedPrefix.reader == 0)
+  }
+
   @Test
   func testFullVerifier() throws {
     _ =
@@ -411,6 +463,27 @@ final class FlatbuffersVerifierTests {
     }
   }
 
+  @Test(.bug("https://github.com/google/flatbuffers/issues/9082"))
+  func testRejectsTruncatedScalarVector() {
+    // swiftformat:disable all
+    var byteBuffer = ByteBuffer(bytes: [
+      16, 0, 0, 0,
+      6, 0, 8, 0,
+      4, 0, 0, 0,
+      0, 0, 0, 0,
+      12, 0, 0, 0,
+      8, 0, 0, 0,
+      0, 0, 0, 0,
+      2, 0, 0, 0,
+      65, 66,
+    ])
+    // swiftformat:enable all
+
+    #expect(throws: FlatbuffersErrors.self) {
+      try getCheckedRoot(byteBuffer: &byteBuffer) as Swift_Tests_Vectors
+    }
+  }
+
   @Test
   func testValidUnionBuffer() {
     let string = "Awesome \\\\t\t\nstring!"