test/streams_tests.cpp fails to compile on SunOS / illumos

[hebasto]

While testing #29484, which seems not related to this bug, I've notice the following failure:

$ ./autogen.sh
$ ./configure
$ gmake -C src test/test_bitcoin
...
  CXX      test/test_bitcoin-streams_tests.o
In file included from test/streams_tests.cpp:5:
./streams.h: In instantiation of 'SpanReader& SpanReader::operator>>(T&&) [with T = signed char&]':
test/streams_tests.cpp:148:15:   required from here
./streams.h:114:22: error: no matching function for call to 'Unserialize(SpanReader&, signed char&)'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
In file included from ./streams.h:9:
./serialize.h:284:48: note: candidate: 'template<class Stream, class V>  requires  CharNotInt8<V> void Unserialize(Stream&, V)' (deleted)
  284 | template <typename Stream, CharNotInt8 V> void Unserialize(Stream&, V) = delete; // char serialization forbidden. Use uint8_t or int8_t
      |                                                ^~~~~~~~~~~
./serialize.h:284:48: note:   template argument deduction/substitution failed:
./serialize.h:284:48: note: constraints not satisfied
In file included from /usr/gcc/13/include/c++/13.2.0/compare:37,
                 from /usr/gcc/13/include/c++/13.2.0/bits/stl_pair.h:65,
                 from /usr/gcc/13/include/c++/13.2.0/bits/stl_algobase.h:64,
                 from /usr/gcc/13/include/c++/13.2.0/algorithm:60,
                 from ./prevector.h:13,
                 from ./serialize.h:12:
/usr/gcc/13/include/c++/13.2.0/concepts: In substitution of 'template<class Stream, class V>  requires  CharNotInt8<V> void Unserialize(Stream&, V) [with Stream = SpanReader; V = signed char]':
./streams.h:114:22:   required from 'SpanReader& SpanReader::operator>>(T&&) [with T = signed char&]'
test/streams_tests.cpp:148:15:   required from here
/usr/gcc/13/include/c++/13.2.0/concepts:57:15:   required for the satisfaction of '__same_as<_Tp, _Up>' [with _Tp = signed char; _Up = char]
/usr/gcc/13/include/c++/13.2.0/concepts:62:13:   required for the satisfaction of 'same_as<T, char>' [with T = signed char]
./serialize.h:268:9:   required for the satisfaction of 'CharNotInt8<V>' [with V = signed char]
/usr/gcc/13/include/c++/13.2.0/concepts:57:32: note: the expression 'is_same_v<_Tp, _Up> [with _Tp = signed char; _Up = char]' evaluated to 'false'
   57 |       concept __same_as = std::is_same_v<_Tp, _Up>;
      |                           ~~~~~^~~~~~~~~~~~~~~~~~~
./streams.h: In instantiation of 'SpanReader& SpanReader::operator>>(T&&) [with T = signed char&]':
test/streams_tests.cpp:148:15:   required from here
./serialize.h:285:33: note: candidate: 'template<class Stream> void Unserialize(Stream&, std::byte&)'
  285 | template <typename Stream> void Unserialize(Stream& s, std::byte& a) { a = std::byte{ser_readdata8(s)}; }
      |                                 ^~~~~~~~~~~
./serialize.h:285:33: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'std::byte&'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:286:39: note: candidate: 'template<class Stream> void Unserialize(Stream&, int8_t&)'
  286 | template<typename Stream> inline void Unserialize(Stream& s, int8_t& a  ) { a = ser_readdata8(s); }
      |                                       ^~~~~~~~~~~
./serialize.h:286:39: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'int8_t&' {aka 'char&'}
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:287:39: note: candidate: 'template<class Stream> void Unserialize(Stream&, uint8_t&)'
  287 | template<typename Stream> inline void Unserialize(Stream& s, uint8_t& a ) { a = ser_readdata8(s); }
      |                                       ^~~~~~~~~~~
./serialize.h:287:39: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'uint8_t&' {aka 'unsigned char&'}
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:288:39: note: candidate: 'template<class Stream> void Unserialize(Stream&, int16_t&)'
  288 | template<typename Stream> inline void Unserialize(Stream& s, int16_t& a ) { a = ser_readdata16(s); }
      |                                       ^~~~~~~~~~~
./serialize.h:288:39: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'int16_t&' {aka 'short int&'}
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:289:39: note: candidate: 'template<class Stream> void Unserialize(Stream&, uint16_t&)'
  289 | template<typename Stream> inline void Unserialize(Stream& s, uint16_t& a) { a = ser_readdata16(s); }
      |                                       ^~~~~~~~~~~
./serialize.h:289:39: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'uint16_t&' {aka 'short unsigned int&'}
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:290:39: note: candidate: 'template<class Stream> void Unserialize(Stream&, int32_t&)'
  290 | template<typename Stream> inline void Unserialize(Stream& s, int32_t& a ) { a = ser_readdata32(s); }
      |                                       ^~~~~~~~~~~
./serialize.h:290:39: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'int32_t&' {aka 'int&'}
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:291:39: note: candidate: 'template<class Stream> void Unserialize(Stream&, uint32_t&)'
  291 | template<typename Stream> inline void Unserialize(Stream& s, uint32_t& a) { a = ser_readdata32(s); }
      |                                       ^~~~~~~~~~~
./serialize.h:291:39: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'uint32_t&' {aka 'unsigned int&'}
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:292:39: note: candidate: 'template<class Stream> void Unserialize(Stream&, int64_t&)'
  292 | template<typename Stream> inline void Unserialize(Stream& s, int64_t& a ) { a = ser_readdata64(s); }
      |                                       ^~~~~~~~~~~
./serialize.h:292:39: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'int64_t&' {aka 'long int&'}
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:293:39: note: candidate: 'template<class Stream> void Unserialize(Stream&, uint64_t&)'
  293 | template<typename Stream> inline void Unserialize(Stream& s, uint64_t& a) { a = ser_readdata64(s); }
      |                                       ^~~~~~~~~~~
./serialize.h:293:39: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'uint64_t&' {aka 'long unsigned int&'}
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:294:53: note: candidate: 'template<class Stream, class B, int N>  requires  BasicByte<B> void Unserialize(Stream&, B (&)[N])'
  294 | template <typename Stream, BasicByte B, int N> void Unserialize(Stream& s, B (&a)[N]) { s.read(MakeWritableByteSpan(a)); }
      |                                                     ^~~~~~~~~~~
./serialize.h:294:53: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'B [N]' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:295:61: note: candidate: 'template<class Stream, class B, long unsigned int N>  requires  BasicByte<B> void Unserialize(Stream&, std::array<_Tp, _Nm>&)'
  295 | template <typename Stream, BasicByte B, std::size_t N> void Unserialize(Stream& s, std::array<B, N>& a) { s.read(MakeWritableByteSpan(a)); }
      |                                                             ^~~~~~~~~~~
./serialize.h:295:61: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'std::array<_Tp, _Nm>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:296:46: note: candidate: 'template<class Stream, class B>  requires  BasicByte<B> void Unserialize(Stream&, Span<O>)'
  296 | template <typename Stream, BasicByte B> void Unserialize(Stream& s, Span<B> span) { s.read(AsWritableBytes(span)); }
      |                                              ^~~~~~~~~~~
./serialize.h:296:46: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'Span<O>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:299:40: note: candidate: 'template<class Stream> void Unserialize(Stream&, bool&)'
  299 | template <typename Stream> inline void Unserialize(Stream& s, bool& a) { uint8_t f = ser_readdata8(s); a = f; }
      |                                        ^~~~~~~~~~~
./serialize.h:299:40: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   cannot convert 'obj' (type 'signed char') to type 'bool&'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:809:6: note: candidate: 'template<class Stream, class C> void Unserialize(Stream&, std::__cxx11::basic_string<C>&)'
  809 | void Unserialize(Stream& is, std::basic_string<C>& str)
      |      ^~~~~~~~~~~
./serialize.h:809:6: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'std::__cxx11::basic_string<C>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:835:6: note: candidate: 'template<class Stream, unsigned int N, class T> void Unserialize(Stream&, prevector<N, T>&)'
  835 | void Unserialize(Stream& is, prevector<N, T>& v)
      |      ^~~~~~~~~~~
./serialize.h:835:6: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'prevector<N, T>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:878:6: note: candidate: 'template<class Stream, class T, class A> void Unserialize(Stream&, std::vector<_ValT, _Allocator>&)'
  878 | void Unserialize(Stream& is, std::vector<T, A>& v)
      |      ^~~~~~~~~~~
./serialize.h:878:6: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'std::vector<_ValT, _Allocator>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:908:6: note: candidate: 'template<class Stream, class K, class T> void Unserialize(Stream&, std::pair<_Tp1, _Tp2>&)'
  908 | void Unserialize(Stream& is, std::pair<K, T>& item)
      |      ^~~~~~~~~~~
./serialize.h:908:6: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'std::pair<_Tp1, _Tp2>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:928:6: note: candidate: 'template<class Stream, class K, class T, class Pred, class A> void Unserialize(Stream&, std::map<K, T, Pred, A>&)'
  928 | void Unserialize(Stream& is, std::map<K, T, Pred, A>& m)
      |      ^~~~~~~~~~~
./serialize.h:928:6: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'std::map<K, T, Pred, A>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:955:6: note: candidate: 'template<class Stream, class K, class Pred, class A> void Unserialize(Stream&, std::set<K, Pred, A>&)'
  955 | void Unserialize(Stream& is, std::set<K, Pred, A>& m)
      |      ^~~~~~~~~~~
./serialize.h:955:6: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'std::set<K, Pred, A>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:997:6: note: candidate: 'template<class Stream, class T> void Unserialize(Stream&, std::shared_ptr<const T>&)'
  997 | void Unserialize(Stream& is, std::shared_ptr<const T>& p)
      |      ^~~~~~~~~~~
./serialize.h:997:6: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'std::shared_ptr<const T>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:980:6: note: candidate: 'template<class Stream, class T> void Unserialize(Stream&, std::unique_ptr<const T>&)'
  980 | void Unserialize(Stream& is, std::unique_ptr<const T>& p)
      |      ^~~~~~~~~~~
./serialize.h:980:6: note:   template argument deduction/substitution failed:
./streams.h:114:22: note:   mismatched types 'std::unique_ptr<const T>' and 'signed char'
  114 |         ::Unserialize(*this, obj);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~
./serialize.h:774:6: note: candidate: 'template<class Stream, class T>  requires  Unserializable<T, Stream> void Unserialize(Stream&, T&&)'
  774 | void Unserialize(Stream& is, T&& a)
      |      ^~~~~~~~~~~
./serialize.h:774:6: note:   template argument deduction/substitution failed:
./serialize.h:774:6: note: constraints not satisfied
./serialize.h: In substitution of 'template<class Stream, class T>  requires  Unserializable<T, Stream> void Unserialize(Stream&, T&&) [with Stream = SpanReader; T = signed char&]':
./streams.h:114:22:   required from 'SpanReader& SpanReader::operator>>(T&&) [with T = signed char&]'
test/streams_tests.cpp:148:15:   required from here
./serialize.h:771:9:   required for the satisfaction of 'Unserializable<T, Stream>' [with T = signed char&; Stream = SpanReader]
./serialize.h:771:26:   in requirements with 'T a', 'Stream s' [with T = signed char&; Stream = SpanReader]
./serialize.h:771:65: note: the required expression 'a.Unserialize(s)' is invalid
  771 | concept Unserializable = requires(T a, Stream s) { a.Unserialize(s); };
      |                                                    ~~~~~~~~~~~~~^~~
./streams.h: In instantiation of 'SpanReader& SpanReader::operator>>(T&&) [with T = signed char&]':
test/streams_tests.cpp:148:15:   required from here
...

I believe, it has been broken since #12254.

---

System and compiler details:

$ uname -a
SunOS openindiana 5.11 illumos-064d431af1 i86pc i386 i86pc
$ g++ --version
g++ (OpenIndiana 13.2.0-oi-3) 13.2.0
Copyright (C) 2023 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[maflcko]

Using char is not allowed in serialization code, because the sign of char is unknown/unclear. However, on some systems, int8_t==char, which means that signed char has no serialization helper.

This could be fixed in the serialization code by replacing int8_t by a concept of !CharNotInt8 || std::same_as<T, signed char>. However, my preference would be to completely avoid signed char and just use int8_t in the serialization code. That is, fix the test to use int8_t.

[hebasto]

However, my preference would be to completely avoid signed char and just use int8_t in the serialization code. That is, fix the test to use int8_t.

I lean to agree, considering that signed char is used in tests only.

[maflcko]

Happy to review a pull, if someone creates one.

[hebasto]

Happy to review a pull, if someone creates one.

Please see #29907.