On 4 Jun 2026, at 13:38, Dimitry Andric <[email protected]> wrote:
>
> On 4 Jun 2026, at 12:53, Nuno Teixeira <[email protected]> wrote:
>>
>> Not sure if it is related but I'm seing some ports failing recently with
>> errors bellow.
>> ( error: no viable conversion from ... to 'bool' )
>>
>> Similar fails appears at pkg-fallout:
>>
>> https://pkg-status.freebsd.org/beefy24/data/main-amd64-default/p226b23044ee7_s67df3130159/logs/binaryen-130.log
>> https://pkg-status.freebsd.org/beefy24/data/main-amd64-default/p226b23044ee7_s67df3130159/logs/encryptpad-0.5.0.4_6.log
>>
>> From node24 on main-n286352-73e0d6b44038:
>> ```
>> c++ -o
>> /wrkdirs/usr/ports/www/node24/work/node-v24.16.0/out/Release/obj.target/node_mksnapshot/tools/snapshot/node_mksnapshot.o
>> ../tools/snapshot/node_mksnapshot.cc '-D_GLIBCXX_USE_CXX11_ABI=1'
>> '-D_FILE_OFFSET_BITS=64' '-DNODE_OPENSSL_CONF_NAME=nodejs_conf'
>> '-DNODE_OPENSSL_CERT_STORE' '-DICU_NO_USER_DATA_OVERRIDE'
>> '-D__STDC_FORMAT_MACROS' '-DNODE_WANT_INTERNALS=1'
>> '-DNODE_MKSNAPSHOT_USE_ARRAY_LITERALS=1' '-DHAVE_OPENSSL=1'
>> '-DNODE_USE_NODE_CODE_CACHE=1' '-DHAVE_INSPECTOR=1' '-D__POSIX__'
>> '-DNODE_USE_V8_PLATFORM=1' '-DNODE_HAVE_I18N_SUPPORT=1' '-DHAVE_AMARO=1'
>> '-DHAVE_SQLITE=1' '-DHAVE_QUIC=0' -I../src -I../tools/msvs/genfiles
>> -I../deps/v8/include -I../deps/cares/include -I../deps/uv/include
>> -I../deps/ncrypto -I../deps/v8/third_party/simdutf -Wall -Wextra
>> -Wno-unused-parameter -pthread -Wall -Wextra -Wno-unused-parameter
>> -Werror=undefined-inline -Werror=extra-semi -Werror=ctad-maybe-unsupported
>> -m64 -O3 -fno-omit-frame-pointer -fno-rtti -fno-exceptions
>> -fno-strict-aliasing -std=gnu++20 -MMD -MF
>> /wrkdirs/usr/ports/www/node24/work/node-v24.16.0/out/Release/.deps//wrkdirs/usr/ports/www/node24/work/node-v24.16.0/out/Release/obj.target/node_mksnapshot/tools/snapshot/node_mksnapshot.o.d.raw
>> -isystem /usr/local/include -O2 -pipe -fstack-protector-strong -isystem
>> /usr/local/include -fno-strict-aliasing -isystem /usr/local/include -c
>> ../test/embedding/embedtest.cc:138:12: error: no viable conversion from
>> 'node::EmbedderSnapshotData::Pointer' (aka 'unique_ptr<const
>> EmbedderSnapshotData, DeleteSnapshotData>') to 'bool'
>> 138 | assert(snapshot);
>> | ^~~~~~~~
>> /usr/include/c++/v1/__memory/unique_ptr.h:276:64: note: explicit conversion
>> function is not a candidate
>> 276 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 explicit
>> operator bool() const _NOEXCEPT {
>> | ^
>> ../test/embedding/embedtest.cc:216:14: error: no viable conversion from
>> 'node::EmbedderSnapshotData::Pointer' (aka 'unique_ptr<const
>> EmbedderSnapshotData, DeleteSnapshotData>') to 'bool'
>> 216 | assert(snapshot);
>> | ^~~~~~~~
>> /usr/include/c++/v1/__memory/unique_ptr.h:276:64: note: explicit conversion
>> function is not a candidate
>> 276 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 explicit
>> operator bool() const _NOEXCEPT {
>> | ^
>> 2 errors generated.
>> ```
>>
>> Any clues?
>
> This is because converting a std::unique_ptr to bool requires an explicit
> conversion, i.e. "if (my_unique_ptr)" will work, but using it with assert()
> will not.
>
> At least, our assert() as defined in /usr/include/assert.h in -CURRENT, has
> this contorted definition:
>
> #if __cplusplus < 202002L
> /*
> * C++ modes prior to C++20 cannot simultaneously satisfy all three
> * desirable properties of the sanitiser:
> *
> * Approach No double-eval Lambda support Arity check
> * ----------------------------- -------------- -------------- -----------
> * sizeof(cast(expression)) yes no yes
> * static_cast<bool>(expression) no yes no
> * (void)bool(expression) no yes no
> *
> * NOTE: C++20 introduced lambdas in unevaluated contexts; see P0315R4.
> *
> * Since no approach satisfies all three below C++20, the least harmful
> * choice is to forgo the check entirely rather than silently break one
> * of the remaining guarantees.
> *
> */
> #define __assert_sanitize(...) ((void)0)
> #else
> #define __assert_sanitize(...) (void)sizeof(((bool(*)(bool))0)(__VA_ARGS__))
> #endif /* __cplusplus < 202002L */
> #else
> #define __assert_sanitize(...)
> (void)sizeof(((_Bool(*)(_Bool))0)(__VA_ARGS__))
> #endif /* __cplusplus */
> #define assert(...) (__assert_sanitize(__VA_ARGS__), \
> (__VA_ARGS__) ? (void)0 : \
> __assert(__func__, __FILE__, \
> __LINE__, #__VA_ARGS__))
>
> which clearly does not work as intended. I would probalby be simpler to to
> use "!!" to force an explicit boolean conversion.
>
> For now, the ports could be fixed by changing the asserts to "ptr != nulltr",
> or adding an explicit static_cast<bool>. Or we should probably fix our assert
> macro.
That is, the following C++20 program should really successfully compile with
our assert():
#include <cassert>
#include <memory>
void f(std::unique_ptr<int> p)
{
assert(p);
}
but at the moment it does not:
unique-ptr-assert.cpp:6:10: error: no viable conversion from
'std::unique_ptr<int>' to 'bool'
6 | assert(p);
| ^
/usr/include/c++/v1/__memory/unique_ptr.h:276:64: note: explicit conversion
function is not a candidate
276 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 explicit operator
bool() const _NOEXCEPT {
| ^
When compiled with -save-temps, it shows the eventual expression it dies on:
unique-ptr-assert.cpp:6:36: error: no viable conversion from
'std::unique_ptr<int>' to 'bool'
6 | ((void)sizeof(((bool(*)(bool))0)(p)), (p) ? (void)0 :
__assert(__func__, "unique-ptr-assert.cpp", 6, "p"));
| ^
So it seems the recent changes to assert.h broke C++20 behavior.
-Dimitry
