clang fails to compile the tree

[tchaikov]

after llvm/llvm-project#109208, clang fails to build the tree:

[14/24] Building CXX object CMakeFiles/seastar.dir/src/rpc/lz4_compressor.cc.o                  
FAILED: CMakeFiles/seastar.dir/src/rpc/lz4_compressor.cc.o                                                             
/home/kefu/.local/bin/clang++ -DFMT_SHARED -DSEASTAR_API_LEVEL=7 -DSEASTAR_DEBUG -DSEASTAR_DEBUG_PROMISE -DSEASTAR_DEBUG_SHARED_PTR -DSEASTAR_DEFAULT_ALLOCATOR -DSEASTAR_DEFERRED_ACTION_REQUIRE_NOEXCEPT -DSEASTAR_DEPRECATED_OSTREAM_FORMAT
TERS -DSEASTAR_HAS_MEMBARRIER -DSEASTAR_HAVE_ASAN_FIBER_SUPPORT -DSEASTAR_HAVE_HWLOC -DSEASTAR_HAVE_NUMA -DSEASTAR_HAVE_SYSTEMTAP_SDT -DSEASTAR_HAVE_URING -DSEASTAR_LOGGER_COMPILE_TIME_FMT -DSEASTAR_LOGGER_TYPE_STDOUT -DSEASTAR_PTHREAD_AT
TR_SETAFFINITY_NP -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_SHUFFLE_TASK_QUEUE -DSEASTAR_SSTRING -DSEASTAR_STRERROR_R_CHAR_P -DSEASTAR_THREAD_STACK_GUARDS -DSEASTAR_TYPE_ERASE_MORE -I/home/kefu/dev/seastar/include -I/home/kefu/dev/se
astar/build/debug/gen/include -I/home/kefu/dev/seastar/build/debug/gen/src -I/home/kefu/dev/seastar/src -isystem /home/kefu/.local/include -g -std=gnu++23 -Wno-error=unused-result "-Wno-error=#warnings" -fstack-clash-protection -UNDEBUG -
Wall -Werror -Wimplicit-fallthrough -Wdeprecated -Wno-error=deprecated -fvisibility=hidden -gz -fsanitize=address -fsanitize=undefined -MD -MT CMakeFiles/seastar.dir/src/rpc/lz4_compressor.cc.o -MF CMakeFiles/seastar.dir/src/rpc/lz4_compr
essor.cc.o.d -o CMakeFiles/seastar.dir/src/rpc/lz4_compressor.cc.o -c /home/kefu/dev/seastar/src/rpc/lz4_compressor.cc
In file included from /home/kefu/dev/seastar/src/rpc/lz4_compressor.cc:22:             
In file included from /home/kefu/dev/seastar/include/seastar/rpc/lz4_compressor.hh:25: 
In file included from /home/kefu/dev/seastar/include/seastar/rpc/rpc_types.hh:28:      
/usr/include/fmt/std.h:166:24: error: call to consteval function 'fmt::basic_format_string<char, const std::filesystem::path &>::basic_format_string<FMT_COMPILE_STRING, 0>' is not a constant expression
  166 |     return fmt::format(FMT_STRING("{}"), base);                                                                
      |                        ^                                                                                       
/usr/include/fmt/format.h:1827:23: note: expanded from macro 'FMT_STRING'              
 1827 | #define FMT_STRING(s) FMT_STRING_IMPL(s, fmt::detail::compile_string, )        
      |                       ^                                                                                        
/usr/include/fmt/format.h:1806:3: note: expanded from macro 'FMT_STRING_IMPL'          
 1806 |   [] {                                                                        \
      |   ^                                                                                                            
/usr/include/fmt/base.h:779:54: note: subexpression not valid in a constant expression 
  779 |     format_str_.remove_prefix(detail::to_unsigned(it - begin()));              
      |                                                   ~~~^~~~~~~~~                 
/usr/include/fmt/base.h:2761:5: note: in call to 'this->context_.advance_to(&"{}"[1])'                                 
 2761 |     context_.advance_to(begin);                                                                                
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~                                                                                 
/usr/include/fmt/base.h:2756:5: note: in call to 'this->on_format_specs(0, &"{}"[1], &"{}"[1])'
 2756 |     on_format_specs(id, begin, begin);  // Call parse() on empty specs.        
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                                                                                                                                                                                                 
/usr/include/fmt/base.h:2581:5: note: in call to 'handler.on_replacement_field(0, &"{}"[1])'                           
 2581 |     handler.on_replacement_field(handler.on_arg_id(), begin);                                                  
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                   
/usr/include/fmt/base.h:2613:21: note: in call to 'parse_replacement_field<char, fmt::detail::format_string_checker<char, std::filesystem::path> &>(&"{}"[1], &"{}"[2], checker(s))'
 2613 |         begin = p = parse_replacement_field(p - 1, end, handler);                                              
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~               
/usr/include/fmt/base.h:2884:7: note: in call to 'parse_format_string<true, char, fmt::detail::format_string_checker<char, std::filesystem::path>>({&"{}"[0], 2}, checker(s))'
 2884 |       detail::parse_format_string<true>(str_, checker(s));                                                     
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                     
/usr/include/fmt/std.h:166:24: note: in call to 'basic_format_string<FMT_COMPILE_STRING, 0>([] {
    struct __attribute__((visibility("hidden")))  FMT_COMPILE_STRING : fmt::detail::compile_string {
        using char_type [[maybe_unused]] = fmt::remove_cvref_t<decltype("{}"[0])>;      
        [[maybe_unused]] constexpr operator fmt::basic_string_view<char_type>() const {
            return fmt::detail_exported::compile_string_to_view<char_type>("{}");
        }                                                                                                              
    };
    return FMT_COMPILE_STRING();
}())'
  166 |     return fmt::format(FMT_STRING("{}"), base);
      |                        ^~~~~~~~~~~~~~~~
/usr/include/fmt/format.h:1827:23: note: expanded from macro 'FMT_STRING'
 1827 | #define FMT_STRING(s) FMT_STRING_IMPL(s, fmt::detail::compile_string, )
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/fmt/format.h:1806:3: note: expanded from macro 'FMT_STRING_IMPL'
 1806 |   [] {                                                                        \
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1807 |     /* Use the hidden visibility as a workaround for a GCC bug (#1973). */    \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1808 |     /* Use a macro-like name to avoid shadowing warnings. */                  \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1809 |     struct FMT_VISIBILITY("hidden") FMT_COMPILE_STRING : base {               \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1810 |       using char_type FMT_MAYBE_UNUSED = fmt::remove_cvref_t<decltype(s[0])>; \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1811 |       FMT_MAYBE_UNUSED FMT_CONSTEXPR explicit                                 \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1812 |       operator fmt::basic_string_view<char_type>() const {                    \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1813 |         return fmt::detail_exported::compile_string_to_view<char_type>(s);    \
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1814 |       }                                                                       \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1815 |     };                                                                        \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1816 |     return FMT_COMPILE_STRING();                                              \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1817 |   }()
      |   ~~~
In file included from /home/kefu/dev/seastar/src/rpc/lz4_compressor.cc:22:
In file included from /home/kefu/dev/seastar/include/seastar/rpc/lz4_compressor.hh:25:
In file included from /home/kefu/dev/seastar/include/seastar/rpc/rpc_types.hh:28:
/usr/include/fmt/std.h:172:24: error: call to consteval function 'fmt::basic_format_string<char, const std::filesystem::path &>::basic_format_string<FMT_COMPILE_STRING, 0>' is not a constant expression
  172 |     return fmt::format(FMT_STRING("{:g}"), base);
      |                        ^
/usr/include/fmt/format.h:1827:23: note: expanded from macro 'FMT_STRING'
 1827 | #define FMT_STRING(s) FMT_STRING_IMPL(s, fmt::detail::compile_string, )
      |                       ^
/usr/include/fmt/format.h:1806:3: note: expanded from macro 'FMT_STRING_IMPL'
 1806 |   [] {                                                                        \
      |   ^
/usr/include/fmt/base.h:779:54: note: subexpression not valid in a constant expression
  779 |     format_str_.remove_prefix(detail::to_unsigned(it - begin()));
      |                                                   ~~~^~~~~~~~~
/usr/include/fmt/base.h:2761:5: note: in call to 'this->context_.advance_to(&"{:g}"[2])'
 2761 |     context_.advance_to(begin);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/fmt/base.h:2591:15: note: in call to 'handler.on_format_specs(0, &"{:g}"[2], &"{:g}"[4])'
 2591 |       begin = handler.on_format_specs(adapter.arg_id, begin + 1, end);
      |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/fmt/base.h:2613:21: note: in call to 'parse_replacement_field<char, fmt::detail::format_string_checker<char, std::filesystem::path> &>(&"{:g}"[1], &"{:g}"[4], checker(s))'
 2613 |         begin = p = parse_replacement_field(p - 1, end, handler);
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/fmt/base.h:2884:7: note: in call to 'parse_format_string<true, char, fmt::detail::format_string_checker<char, std::filesystem::path>>({&"{:g}"[0], 4}, checker(s))'
 2884 |       detail::parse_format_string<true>(str_, checker(s));
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/fmt/std.h:172:24: note: in call to 'basic_format_string<FMT_COMPILE_STRING, 0>([] {
    struct __attribute__((visibility("hidden")))  FMT_COMPILE_STRING : fmt::detail::compile_string {
        using char_type [[maybe_unused]] = fmt::remove_cvref_t<decltype("{:g}"[0])>;
        [[maybe_unused]] constexpr operator fmt::basic_string_view<char_type>() const {
            return fmt::detail_exported::compile_string_to_view<char_type>("{:g}");
        }
    };
    return FMT_COMPILE_STRING();
}())'
  172 |     return fmt::format(FMT_STRING("{:g}"), base);
      |                        ^~~~~~~~~~~~~~~~~~
/usr/include/fmt/format.h:1827:23: note: expanded from macro 'FMT_STRING'
 1827 | #define FMT_STRING(s) FMT_STRING_IMPL(s, fmt::detail::compile_string, )
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/fmt/format.h:1806:3: note: expanded from macro 'FMT_STRING_IMPL'
 1806 |   [] {                                                                        \
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1807 |     /* Use the hidden visibility as a workaround for a GCC bug (#1973). */    \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1808 |     /* Use a macro-like name to avoid shadowing warnings. */                  \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1809 |     struct FMT_VISIBILITY("hidden") FMT_COMPILE_STRING : base {               \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1810 |       using char_type FMT_MAYBE_UNUSED = fmt::remove_cvref_t<decltype(s[0])>; \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1811 |       FMT_MAYBE_UNUSED FMT_CONSTEXPR explicit                                 \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1812 |       operator fmt::basic_string_view<char_type>() const {                    \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1813 |         return fmt::detail_exported::compile_string_to_view<char_type>(s);    \
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1814 |       }                                                                       \
      |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1815 |     };                                                                        \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1816 |     return FMT_COMPILE_STRING();                                              \
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1817 |   }()
      |   ~~~
2 errors generated.

this issue was reported in the LLVM mailing list at https://www.mail-archive.com/[email protected]/msg482152.html . and turns out to be a bug in fmt. it has been fixed upstream. see fmtlib/fmt#4187

[tchaikov]

this issue was created for those who are testing with clang HEAD.

meanwhile, fmt packages in fedora 40, fedora 41 and fedora 42 (rawhide) are being updated.

• f40: https://bodhi.fedoraproject.org/updates/FEDORA-2024-791994e69b
• f41: https://bodhi.fedoraproject.org/updates/FEDORA-2024-d50745b8f8
• f42: https://bodhi.fedoraproject.org/updates/FEDORA-2024-7f844c2f89

since this issue cannot be addressed by seastar, and has been resolved upstream. i am closing it.