CXX-2139 update clang-tidy configuration with WarningsAsErrors

.clang-tidy

@@ -1,2 +1,128 @@
-Checks:          'clang-diagnostic-*,clang-analyzer-*,-*,cert-*,cppcoreguidelines-*,clang-analyzer-*'
-WarningsAsErrors: ''
+---
+Checks:
+  - -*
+  - cert-*
+  - cppcoreguidelines-*
+  - clang-analyzer-*'
+  - -cppcoreguidelines-pro-bounds-array-to-pointer-decay # Noise.
+  - -cppcoreguidelines-pro-bounds-constant-array-index # Noise.
+  - -cppcoreguidelines-pro-bounds-pointer-arithmetic # Noise.
+  - -cppcoreguidelines-pro-type-union-access # Requires C++17 or newer for `std::variant`.
+WarningsAsErrors: '*,-cert-err58-cpp,-cppcoreguidelines-avoid-do-while,-cppcoreguidelines-avoid-non-const-global-variables,-cppcoreguidelines-pro-type-union-access,-cppcoreguidelines-pro-type-vararg,-cppcoreguidelines-rvalue-reference-param-not-moved'
+HeaderFileExtensions:
+  - ''
+  - h
+  - hh
+  - hpp
+  - hxx
+ImplementationFileExtensions:
+  - c
+  - cc
+  - cpp
+  - cxx
+HeaderFilterRegex: ''
+ExcludeHeaderFilterRegex: '(?:.*/bsoncxx/enums/.*|.*/(?:prelude|postlude)\.hpp$)'
+FormatStyle:     none
+User:            ''
+CheckOptions:
+  cert-arr39-c.WarnOnOffsetDividedBySizeOf: 'true'
+  cert-arr39-c.WarnOnSizeOfCompareToConstant: 'false'
+  cert-arr39-c.WarnOnSizeOfConstant: 'false'
+  cert-arr39-c.WarnOnSizeOfInLoopTermination: 'true'
+  cert-arr39-c.WarnOnSizeOfIntegerExpression: 'false'
+  cert-arr39-c.WarnOnSizeOfPointer: 'false'
+  cert-arr39-c.WarnOnSizeOfPointerToAggregate: 'false'
+  cert-arr39-c.WarnOnSizeOfThis: 'false'
+  cert-ctr56-cpp.IgnoreInheritedVirtualFunctions: 'false'
+  cert-dcl16-c.IgnoreMacros: 'true'
+  cert-dcl16-c.NewSuffixes: 'L;LL;LU;LLU'
+  cert-dcl37-c.AggressiveDependentMemberLookup: 'false'
+  cert-dcl37-c.AllowedIdentifiers: ''
+  cert-dcl37-c.Invert: 'false'
+  cert-dcl51-cpp.AggressiveDependentMemberLookup: 'false'
+  cert-dcl51-cpp.AllowedIdentifiers: ''
+  cert-dcl51-cpp.Invert: 'false'
+  cert-err09-cpp.CheckThrowTemporaries: 'true'
+  cert-err09-cpp.MaxSize: '18446744073709551615'
+  cert-err09-cpp.WarnOnLargeObjects: 'false'
+  cert-err33-c.AllowCastToVoid: 'true'
+  cert-err33-c.CheckedFunctions: '^::aligned_alloc$;^::asctime_s$;^::at_quick_exit$;^::atexit$;^::bsearch$;^::bsearch_s$;^::btowc$;^::c16rtomb$;^::c32rtomb$;^::calloc$;^::clock$;^::cnd_broadcast$;^::cnd_init$;^::cnd_signal$;^::cnd_timedwait$;^::cnd_wait$;^::ctime_s$;^::fclose$;^::fflush$;^::fgetc$;^::fgetpos$;^::fgets$;^::fgetwc$;^::fopen$;^::fopen_s$;^::fprintf$;^::fprintf_s$;^::fputc$;^::fputs$;^::fputwc$;^::fputws$;^::fread$;^::freopen$;^::freopen_s$;^::fscanf$;^::fscanf_s$;^::fseek$;^::fsetpos$;^::ftell$;^::fwprintf$;^::fwprintf_s$;^::fwrite$;^::fwscanf$;^::fwscanf_s$;^::getc$;^::getchar$;^::getenv$;^::getenv_s$;^::gets_s$;^::getwc$;^::getwchar$;^::gmtime$;^::gmtime_s$;^::localtime$;^::localtime_s$;^::malloc$;^::mbrtoc16$;^::mbrtoc32$;^::mbsrtowcs$;^::mbsrtowcs_s$;^::mbstowcs$;^::mbstowcs_s$;^::memchr$;^::mktime$;^::mtx_init$;^::mtx_lock$;^::mtx_timedlock$;^::mtx_trylock$;^::mtx_unlock$;^::printf_s$;^::putc$;^::putwc$;^::raise$;^::realloc$;^::remove$;^::rename$;^::scanf$;^::scanf_s$;^::setlocale$;^::setvbuf$;^::signal$;^::snprintf$;^::snprintf_s$;^::sprintf$;^::sprintf_s$;^::sscanf$;^::sscanf_s$;^::strchr$;^::strerror_s$;^::strftime$;^::strpbrk$;^::strrchr$;^::strstr$;^::strtod$;^::strtof$;^::strtoimax$;^::strtok$;^::strtok_s$;^::strtol$;^::strtold$;^::strtoll$;^::strtoul$;^::strtoull$;^::strtoumax$;^::strxfrm$;^::swprintf$;^::swprintf_s$;^::swscanf$;^::swscanf_s$;^::thrd_create$;^::thrd_detach$;^::thrd_join$;^::thrd_sleep$;^::time$;^::timespec_get$;^::tmpfile$;^::tmpfile_s$;^::tmpnam$;^::tmpnam_s$;^::tss_create$;^::tss_get$;^::tss_set$;^::ungetc$;^::ungetwc$;^::vfprintf$;^::vfprintf_s$;^::vfscanf$;^::vfscanf_s$;^::vfwprintf$;^::vfwprintf_s$;^::vfwscanf$;^::vfwscanf_s$;^::vprintf_s$;^::vscanf$;^::vscanf_s$;^::vsnprintf$;^::vsnprintf_s$;^::vsprintf$;^::vsprintf_s$;^::vsscanf$;^::vsscanf_s$;^::vswprintf$;^::vswprintf_s$;^::vswscanf$;^::vswscanf_s$;^::vwprintf_s$;^::vwscanf$;^::vwscanf_s$;^::wcrtomb$;^::wcschr$;^::wcsftime$;^::wcspbrk$;^::wcsrchr$;^::wcsrtombs$;^::wcsrtombs_s$;^::wcsstr$;^::wcstod$;^::wcstof$;^::wcstoimax$;^::wcstok$;^::wcstok_s$;^::wcstol$;^::wcstold$;^::wcstoll$;^::wcstombs$;^::wcstombs_s$;^::wcstoul$;^::wcstoull$;^::wcstoumax$;^::wcsxfrm$;^::wctob$;^::wctrans$;^::wctype$;^::wmemchr$;^::wprintf_s$;^::wscanf$;^::wscanf_s$'
+  cert-err33-c.CheckedReturnTypes: '^::std::error_code$;^::std::error_condition$;^::std::errc$;^::std::expected$;^::boost::system::error_code$'
+  cert-err61-cpp.CheckThrowTemporaries: 'true'
+  cert-err61-cpp.MaxSize: '18446744073709551615'
+  cert-err61-cpp.WarnOnLargeObjects: 'false'
+  cert-int09-c.AllowExplicitSequentialInitialValues: 'true'
+  cert-int09-c.AllowExplicitZeroFirstInitialValue: 'true'
+  cert-msc24-c.CustomFunctions: ''
+  cert-msc24-c.ReportDefaultFunctions: 'true'
+  cert-msc24-c.ReportMoreUnsafeFunctions: 'true'
+  cert-msc32-c.DisallowedSeedTypes: 'time_t,std::time_t'
+  cert-msc33-c.CustomFunctions: ''
+  cert-msc33-c.ReportDefaultFunctions: 'true'
+  cert-msc33-c.ReportMoreUnsafeFunctions: 'true'
+  cert-msc51-cpp.DisallowedSeedTypes: 'time_t,std::time_t'
+  cert-msc54-cpp.AsyncSafeFunctionSet: POSIX
+  cert-oop54-cpp.WarnOnlyIfThisHasSuspiciousField: 'false'
+  cert-oop57-cpp.MemCmpNames: ''
+  cert-oop57-cpp.MemCpyNames: ''
+  cert-oop57-cpp.MemSetNames: ''
+  cert-sig30-c.AsyncSafeFunctionSet: POSIX
+  cert-str34-c.CharTypdefsToIgnore: ''
+  cert-str34-c.DiagnoseSignedUnsignedCharComparisons: 'false'
+  cppcoreguidelines-avoid-c-arrays.AllowStringArrays: 'false'
+  cppcoreguidelines-avoid-do-while.IgnoreMacros: 'false'
+  cppcoreguidelines-avoid-goto.IgnoreMacros: 'false'
+  cppcoreguidelines-avoid-magic-numbers.IgnoreAllFloatingPointValues: 'false'
+  cppcoreguidelines-avoid-magic-numbers.IgnoreBitFieldsWidths: 'true'
+  cppcoreguidelines-avoid-magic-numbers.IgnorePowersOf2IntegerValues: 'false'
+  cppcoreguidelines-avoid-magic-numbers.IgnoreTypeAliases: 'false'
+  cppcoreguidelines-avoid-magic-numbers.IgnoreUserDefinedLiterals: 'false'
+  cppcoreguidelines-avoid-magic-numbers.IgnoredFloatingPointValues: '1.0;100.0;'
+  cppcoreguidelines-avoid-magic-numbers.IgnoredIntegerValues: '1;2;3;4;'
+  cppcoreguidelines-avoid-non-const-global-variables.AllowInternalLinkage: 'false'
+  cppcoreguidelines-explicit-virtual-functions.AllowOverrideAndFinal: 'false'
+  cppcoreguidelines-explicit-virtual-functions.FinalSpelling: final
+  cppcoreguidelines-explicit-virtual-functions.IgnoreDestructors: 'false'
+  cppcoreguidelines-explicit-virtual-functions.IgnoreTemplateInstantiations: 'false'
+  cppcoreguidelines-explicit-virtual-functions.OverrideSpelling: override
+  cppcoreguidelines-init-variables.IncludeStyle: llvm
+  cppcoreguidelines-init-variables.MathHeader: '<math.h>'
+  cppcoreguidelines-macro-usage.AllowedRegexp: '^DEBUG_*'
+  cppcoreguidelines-macro-usage.CheckCapsOnly: 'false'
+  cppcoreguidelines-macro-usage.IgnoreCommandLineMacros: 'true'
+  cppcoreguidelines-missing-std-forward.ForwardFunction: '::std::forward'
+  cppcoreguidelines-narrowing-conversions.IgnoreConversionFromTypes: ''
+  cppcoreguidelines-narrowing-conversions.PedanticMode: 'false'
+  cppcoreguidelines-narrowing-conversions.WarnOnEquivalentBitWidth: 'true'
+  cppcoreguidelines-narrowing-conversions.WarnOnFloatingPointNarrowingConversion: 'true'
+  cppcoreguidelines-narrowing-conversions.WarnOnIntegerNarrowingConversion: 'true'
+  cppcoreguidelines-narrowing-conversions.WarnOnIntegerToFloatingPointNarrowingConversion: 'true'
+  cppcoreguidelines-narrowing-conversions.WarnWithinTemplateInstantiation: 'false'
+  cppcoreguidelines-no-malloc.Allocations: '::malloc;::calloc'
+  cppcoreguidelines-no-malloc.Deallocations: '::free'
+  cppcoreguidelines-no-malloc.Reallocations: '::realloc'
+  cppcoreguidelines-no-suspend-with-lock.LockGuards: '::std::unique_lock;::std::scoped_lock;::std::shared_lock;::std::lock_guard'
+  cppcoreguidelines-non-private-member-variables-in-classes.IgnoreClassesWithAllMemberVariablesBeingPublic: 'true'
+  cppcoreguidelines-non-private-member-variables-in-classes.IgnorePublicMemberVariables: 'false'
+  cppcoreguidelines-owning-memory.LegacyResourceConsumers: '::free;::realloc;::freopen;::fclose'
+  cppcoreguidelines-owning-memory.LegacyResourceProducers: '::malloc;::aligned_alloc;::realloc;::calloc;::fopen;::freopen;::tmpfile'
+  cppcoreguidelines-pro-bounds-constant-array-index.GslHeader: ''
+  cppcoreguidelines-pro-bounds-constant-array-index.IncludeStyle: llvm
+  cppcoreguidelines-pro-type-const-cast.StrictMode: 'false'
+  cppcoreguidelines-pro-type-member-init.IgnoreArrays: 'false'
+  cppcoreguidelines-pro-type-member-init.UseAssignment: 'false'
+  cppcoreguidelines-pro-type-static-cast-downcast.StrictMode: 'true'
+  cppcoreguidelines-rvalue-reference-param-not-moved.AllowPartialMove: 'false'
+  cppcoreguidelines-rvalue-reference-param-not-moved.IgnoreNonDeducedTemplateTypes: 'false'
+  cppcoreguidelines-rvalue-reference-param-not-moved.IgnoreUnnamedParams: 'false'
+  cppcoreguidelines-rvalue-reference-param-not-moved.MoveFunction: '::std::move'
+  cppcoreguidelines-special-member-functions.AllowImplicitlyDeletedCopyOrMove: 'false'
+  cppcoreguidelines-special-member-functions.AllowMissingMoveFunctions: 'false'
+  cppcoreguidelines-special-member-functions.AllowMissingMoveFunctionsWhenCopyIsDeleted: 'false'
+  cppcoreguidelines-special-member-functions.AllowSoleDefaultDtor: 'false'
+  cppcoreguidelines-special-member-functions.IgnoreMacros: 'true'
+  cppcoreguidelines-use-default-member-init.IgnoreMacros: 'true'
+  cppcoreguidelines-use-default-member-init.UseAssignment: 'false'
+  cppcoreguidelines-use-enum-class.IgnoreUnscopedEnumsInClasses: 'true'
+SystemHeaders:   false
+...

etc/run-clang-tidy.sh

@@ -20,7 +20,8 @@ install_build_tools
 export CMAKE_GENERATOR="Ninja"
 
 uv tool install -q clang-tidy
-clang-tidy --version
+version="$(clang-tidy --version | perl -lne 'print $1 if m|LLVM version (\d+\.\d+\.\d+)|')"
+echo "clang-tidy version: ${version:?}"
 
 # Use ccache if available.
 if [[ -f "../mongoc/.evergreen/scripts/find-ccache.sh" ]]; then
@@ -37,41 +38,14 @@ cmake_config_flags=(
 )
 
 # Generate the compilation database file.
-cmake -S . -B build "${cmake_config_flags[@]}"
+cmake "${cmake_config_flags[@]}" -B build
 
-# Some files (i.e. headers) may need to be generated during the build step.
-cmake --build build
+mapfile -t sources < <(find src -type f \( -name *.cc -o -name *.cpp \) | perl -lne 'print if m$.*/(?:bsoncxx|mongocxx)/lib/.*$')
 
-#
-# Each check has a name and the checks to run can be chosen using the -checks= option, which specifies a comma-separated
-# list of positive and negative (prefixed with -) globs. For example:
-#
-#    $ clang-tidy test.cpp -checks=-*,clang-analyzer-*,-clang-analyzer-cplusplus*
-#
-# will disable all default checks (-*) and enable all clang-analyzer-* checks except for clang-analyzer-cplusplus* ones.
-#
-# The -list-checks option lists all the enabled checks. When used without -checks=, it shows checks enabled by default.
-# Use -checks=* to see all available checks or with any other value of -checks= to see which checks are enabled by this
-# value.
-#
-# see https://clang.llvm.org/extra/clang-tidy
-#
-
-echo "Running clang-tidy with configuration:"
-clang-tidy -p=build -dump-config
-
-find_args=(
-  -type f
-  \( -name *.hh -o -name *.hpp -o -name *.cpp \)    # All sources including headers.
-  -not -path "*/third_party/*"                      # Excluding third party headers.
-  -not -path "*/config/*.hpp"                       # Excluding config headers.
-  -not -path "*bsoncxx/v_noabi/bsoncxx/enums/*.hpp" # Excluding X macro headers.
+clang_tidy_flags=(
+  --quiet
+  -p build
+  --header-filter '.*/(?:bsoncxx|mongocxx)/(?:include|lib)/.*'
 )
 
-echo "Scanning the following files:"
-find src "${find_args[@]}" | sed -E -e 's/^/ - /'
-
-# TODO: update clang-tidy config and address warnings.
-{
-  find src "${find_args[@]}" | parallel clang-tidy --quiet -p=build {} 2>/dev/null
-} || true
+printf "%s\n" "${sources[@]}" | parallel -q "${parallel_flags[@]}" clang-tidy "${clang_tidy_flags[@]:?}" {} 2>/dev/null

src/bsoncxx/lib/bsoncxx/private/itoa.cpp

@@ -18,6 +18,8 @@ namespace bsoncxx {
 
 namespace {
 
+// Precomputed table of C strings.
+// NOLINTNEXTLINE(cppcoreguidelines-avoid-c-arrays)
 constexpr char k_index_table[] =
     "0\0"
     "1\0"
@@ -1032,17 +1034,25 @@ itoa& itoa::operator=(std::uint32_t new_val) {
     return *this;
 }
 
+// Index the precomputed table by powers of 10 with additional offsets to account for intermediate null terminators.
+// NOLINTBEGIN(cppcoreguidelines-avoid-magic-numbers)
 void itoa::_init() {
     if (_val < 10u) {
+        // Index by (single digit + null terminator).
         _str = k_index_table + (2u * _val);
         _len = 1u;
     } else if (_val < 100u) {
-        _str = k_index_table + (2u * 10u) + (3u * (_val - 10u));
+        // Index by (double digit + null terminator) and skip lower entries.
+        _str = k_index_table + (3u * (_val - 10u)) + (2u * 10u);
         _len = 2u;
     } else if (_val < 1000u) {
-        _str = k_index_table + (2u * 10u) + (3u * 90u) + (4 * (_val - 100u));
+        // Index by (triple digit + null terminator) and skip lower entries.
+        _str = k_index_table + (4u * (_val - 100u)) + (2u * 10u) + (3u * 90u);
         _len = 3u;
-    } else {
+    }
+
+    // Fallback to traditional algorithm.
+    else {
         int size = static_cast<std::int32_t>(sizeof(_buf) - 1u);
         int i = size;
 
@@ -1058,5 +1068,6 @@ void itoa::_init() {
         _len = static_cast<std::uint8_t>(size - i);
     }
 }
+// NOLINTEND(cppcoreguidelines-avoid-magic-numbers)
 
 } // namespace bsoncxx

src/bsoncxx/lib/bsoncxx/private/itoa.hh

@@ -23,10 +23,14 @@ namespace bsoncxx {
 
 class itoa {
    private:
-    std::uint32_t _val;
-    char const* _str;
-    std::uint8_t _len;
-    char _buf[11];
+    // Exact value of UINT32_MAX for `sizeof()` below.
+    // NOLINTNEXTLINE(cppcoreguidelines-avoid-magic-numbers).
+    static_assert(UINT32_MAX == std::uint32_t{4294967295}, "");
+
+    std::uint32_t _val = {};
+    char const* _str = {};
+    std::uint8_t _len = {};
+    char _buf[sizeof("4294967295")] = {};
 
    public:
     ~itoa() = default;

src/bsoncxx/lib/bsoncxx/private/version.cpp

@@ -30,7 +30,7 @@ std::vector<int> split_version(bsoncxx::stdx::string_view input) {
 
     std::vector<int> ret;
 
-    std::size_t pos;
+    std::size_t pos = {};
 
     while ((pos = input.find_first_not_of(digits)) != npos) {
         auto const str = input.substr(0u, pos);

src/bsoncxx/lib/bsoncxx/v1/decimal128.cpp

@@ -19,6 +19,7 @@
 #include <bsoncxx/v1/exception.hpp>
 #include <bsoncxx/v1/stdx/string_view.hpp>
 
+#include <array>
 #include <climits>
 #include <cstddef>
 #include <string>
@@ -59,9 +60,9 @@ std::string decimal128::to_string() const {
     bson_decimal128_t d128;
     d128.high = _high;
     d128.low = _low;
-    char str[BSON_DECIMAL128_STRING];
-    bson_decimal128_to_string(&d128, str);
-    return {str};
+    std::array<char, BSON_DECIMAL128_STRING> str = {};
+    bson_decimal128_to_string(&d128, str.data());
+    return {str.data()};
 }
 
 std::error_category const& decimal128::error_category() {

src/bsoncxx/lib/bsoncxx/v1/element/view.cpp

@@ -156,6 +156,8 @@ class alignas(BSONCXX_PRIVATE_MAX_ALIGN_T) view::impl {
         throw v1::exception{code::invalid_data};
     }
 
+    // Helpers to access the inline PIMPL object.
+    // NOLINTBEGIN(cppcoreguidelines-pro-type-reinterpret-cast)
     static impl const& with(view const& v) {
         return *reinterpret_cast<view::impl const*>(v._storage.data());
     }
@@ -167,6 +169,7 @@ class alignas(BSONCXX_PRIVATE_MAX_ALIGN_T) view::impl {
     static impl* with(view* v) {
         return reinterpret_cast<view::impl*>(v->_storage.data());
     }
+    // NOLINTEND(cppcoreguidelines-pro-type-reinterpret-cast)
 };
 
 void view::impl::check() const {
@@ -192,19 +195,26 @@ void view::impl::check() const {
 
 view::~view() = default;
 
+// _storage: initialized with placement new.
+// NOLINTNEXTLINE(cppcoreguidelines-pro-type-member-init)
 view::view(view const& other) noexcept {
-    new (impl::with(this)) impl{impl::with(other)};
+    new (_storage.data()) impl{impl::with(other)};
 }
 
+// NOLINTNEXTLINE(cert-oop54-cpp): handled by impl.
 view& view::operator=(view const& other) noexcept {
     *impl::with(this) = impl::with(other);
     return *this;
 }
 
+// _storage: initialized with placement new.
+// NOLINTNEXTLINE(cppcoreguidelines-pro-type-member-init)
 view::view() {
     new (_storage.data()) impl{};
 }
 
+// _storage: initialized with placement new.
+// NOLINTNEXTLINE(cppcoreguidelines-pro-type-member-init)
 view::view(impl i) {
     new (_storage.data()) impl{i};
 }

src/bsoncxx/lib/bsoncxx/v1/oid.cpp

@@ -19,6 +19,7 @@
 #include <bsoncxx/v1/exception.hpp>
 #include <bsoncxx/v1/stdx/string_view.hpp>
 
+#include <array>
 #include <cstdint>
 #include <cstring>
 #include <ctime>
@@ -37,6 +38,8 @@ using code = v1::oid::errc;
 static_assert(is_regular<oid>::value, "bsoncxx::v1::oid must be regular");
 static_assert(is_semitrivial<oid>::value, "bsoncxx::v1::oid must be semitrivial");
 
+// _bytes: initialized with memcpy.
+// NOLINTNEXTLINE(cppcoreguidelines-pro-type-member-init)
 oid::oid() {
 #if defined(_WIN32)
     // Ensure the Winsock DLL is initialized prior to calling `gethostname` in `bsoncxx::v1::oid::oid()`:
@@ -66,6 +69,8 @@ oid::oid() {
     std::memcpy(_bytes.data(), oid.bytes, sizeof(oid.bytes));
 }
 
+// _bytes: initialized with memcpy.
+// NOLINTNEXTLINE(cppcoreguidelines-pro-type-member-init)
 oid::oid(std::uint8_t const* bytes, std::size_t len) {
     if (!bytes) {
         throw v1::exception{code::null_bytes_ptr};
@@ -78,6 +83,8 @@ oid::oid(std::uint8_t const* bytes, std::size_t len) {
     std::memcpy(_bytes.data(), bytes, _bytes.size());
 }
 
+// _bytes: initialized with memcpy.
+// NOLINTNEXTLINE(cppcoreguidelines-pro-type-member-init)
 oid::oid(v1::stdx::string_view str) {
     if (str.empty()) {
         throw v1::exception{code::empty_string};
@@ -95,9 +102,9 @@ oid::oid(v1::stdx::string_view str) {
 std::string oid::to_string() const {
     bson_oid_t oid;
     std::memcpy(oid.bytes, _bytes.data(), sizeof(oid.bytes));
-    char str[25];
-    bson_oid_to_string(&oid, str);
-    return std::string(str);
+    std::array<char, 2u * k_oid_length + 1u> str = {}; // Two hex digits per byte + null terminator: 25 characters.
+    bson_oid_to_string(&oid, str.data());
+    return std::string(str.data());
 }
 
 std::time_t oid::get_time_t() const {