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Fast C++ logging library.
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spdlog 1.8.5 fails to build with libfmt 8.0.0 #1975

Closed candrews closed 3 years ago

candrews commented 3 years ago

Trying to build spdlog 1.8.5 with libfmt 8.0.0 fails with this error:

ninja -v -j5 -l0
[1/8] /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DFMT_LOCALE -DFMT_SHARED -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL -DSPDLOG_SHARED_LIB -Dspdlog_EXPORTS -I/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include  -O2 -march=native -pipe -fuse-linker-plugin -flto -Wl,-flto -ftree-vectorize -falign-functions=32 -fgraphite-identity -floop-nest-optimize -fno-common -fPIC -std=c++11 -MD -MT CMakeFiles/spdlog.dir/src/file_sinks.cpp.o -MF CMakeFiles/spdlog.dir/src/file_sinks.cpp.o.d -o CMakeFiles/spdlog.dir/src/file_sinks.cpp.o -c /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/file_sinks.cpp
[2/8] /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DFMT_LOCALE -DFMT_SHARED -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL -DSPDLOG_SHARED_LIB -Dspdlog_EXPORTS -I/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include  -O2 -march=native -pipe -fuse-linker-plugin -flto -Wl,-flto -ftree-vectorize -falign-functions=32 -fgraphite-identity -floop-nest-optimize -fno-common -fPIC -std=c++11 -MD -MT CMakeFiles/spdlog.dir/src/async.cpp.o -MF CMakeFiles/spdlog.dir/src/async.cpp.o.d -o CMakeFiles/spdlog.dir/src/async.cpp.o -c /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/async.cpp
[3/8] /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DFMT_LOCALE -DFMT_SHARED -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL -DSPDLOG_SHARED_LIB -Dspdlog_EXPORTS -I/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include  -O2 -march=native -pipe -fuse-linker-plugin -flto -Wl,-flto -ftree-vectorize -falign-functions=32 -fgraphite-identity -floop-nest-optimize -fno-common -fPIC -std=c++11 -MD -MT CMakeFiles/spdlog.dir/src/stdout_sinks.cpp.o -MF CMakeFiles/spdlog.dir/src/stdout_sinks.cpp.o.d -o CMakeFiles/spdlog.dir/src/stdout_sinks.cpp.o -c /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/stdout_sinks.cpp
[4/8] /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DFMT_LOCALE -DFMT_SHARED -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL -DSPDLOG_SHARED_LIB -Dspdlog_EXPORTS -I/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include  -O2 -march=native -pipe -fuse-linker-plugin -flto -Wl,-flto -ftree-vectorize -falign-functions=32 -fgraphite-identity -floop-nest-optimize -fno-common -fPIC -std=c++11 -MD -MT CMakeFiles/spdlog.dir/src/color_sinks.cpp.o -MF CMakeFiles/spdlog.dir/src/color_sinks.cpp.o.d -o CMakeFiles/spdlog.dir/src/color_sinks.cpp.o -c /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/color_sinks.cpp
[5/8] /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DFMT_LOCALE -DFMT_SHARED -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL -DSPDLOG_SHARED_LIB -Dspdlog_EXPORTS -I/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include  -O2 -march=native -pipe -fuse-linker-plugin -flto -Wl,-flto -ftree-vectorize -falign-functions=32 -fgraphite-identity -floop-nest-optimize -fno-common -fPIC -std=c++11 -MD -MT CMakeFiles/spdlog.dir/src/cfg.cpp.o -MF CMakeFiles/spdlog.dir/src/cfg.cpp.o.d -o CMakeFiles/spdlog.dir/src/cfg.cpp.o -c /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/cfg.cpp
[6/8] /usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DFMT_LOCALE -DFMT_SHARED -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL -DSPDLOG_SHARED_LIB -Dspdlog_EXPORTS -I/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include  -O2 -march=native -pipe -fuse-linker-plugin -flto -Wl,-flto -ftree-vectorize -falign-functions=32 -fgraphite-identity -floop-nest-optimize -fno-common -fPIC -std=c++11 -MD -MT CMakeFiles/spdlog.dir/src/spdlog.cpp.o -MF CMakeFiles/spdlog.dir/src/spdlog.cpp.o.d -o CMakeFiles/spdlog.dir/src/spdlog.cpp.o -c /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/spdlog.cpp
FAILED: CMakeFiles/spdlog.dir/src/spdlog.cpp.o 
/usr/lib/ccache/bin/x86_64-pc-linux-gnu-g++ -DFMT_LOCALE -DFMT_SHARED -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL -DSPDLOG_SHARED_LIB -Dspdlog_EXPORTS -I/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include  -O2 -march=native -pipe -fuse-linker-plugin -flto -Wl,-flto -ftree-vectorize -falign-functions=32 -fgraphite-identity -floop-nest-optimize -fno-common -fPIC -std=c++11 -MD -MT CMakeFiles/spdlog.dir/src/spdlog.cpp.o -MF CMakeFiles/spdlog.dir/src/spdlog.cpp.o.d -o CMakeFiles/spdlog.dir/src/spdlog.cpp.o -c /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/spdlog.cpp
In file included from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/spdlog.cpp:9:
/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/common-inl.h: In constructor ‘spdlog::spdlog_ex::spdlog_ex(const string&, int)’:
/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/common-inl.h:63:50: error: cannot convert ‘const string’ {aka ‘const std::__cxx11::basic_string<char>’} to ‘const char*’
   63 |     fmt::format_system_error(outbuf, last_errno, msg);
      |                                                  ^~~
      |                                                  |
      |                                                  const string {aka const std::__cxx11::basic_string<char>}
In file included from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/fmt/fmt.h:26,
                 from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/common.h:36,
                 from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/spdlog.h:12,
                 from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/spdlog-inl.h:7,
                 from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/spdlog.cpp:8:
/usr/include/fmt/format.h:2262:46: note:   initializing argument 3 of ‘void fmt::v7::format_system_error(fmt::v7::detail::buffer<char>&, int, const char*)’
 2262 |                                  const char* message) FMT_NOEXCEPT;
      |                                  ~~~~~~~~~~~~^~~~~~~
In file included from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/pattern_formatter-inl.h:10,
                 from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/spdlog.cpp:13:
/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/details/fmt_helper.h: In function ‘void spdlog::details::fmt_helper::pad2(int, spdlog::memory_buf_t&)’:
/var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/details/fmt_helper.h:57:23: warning: ‘fmt::v7::appender fmt::v7::format_to(fmt::v7::basic_memory_buffer<char, SIZE, Allocator>&, fmt::v7::format_string<T ...>, T&& ...) [with T = {int&}; long unsigned int SIZE = 250; Allocator = std::allocator<char>; fmt::v7::format_string<T ...> = fmt::v7::basic_format_string<char, int&>]’ is deprecated [-Wdeprecated-declarations]
   57 |         fmt::format_to(dest, "{:02}", n);
      |         ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
In file included from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/fmt/fmt.h:26,
                 from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/common.h:36,
                 from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/spdlog.h:12,
                 from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/include/spdlog/spdlog-inl.h:7,
                 from /var/tmp/portage/dev-libs/spdlog-1.8.5/work/spdlog-1.8.5/src/spdlog.cpp:8:
/usr/include/fmt/format.h:2790:21: note: declared here
 2790 | FMT_DEPRECATED auto format_to(basic_memory_buffer<char, SIZE, Allocator>& buf,
      |                     ^~~~~~~~~
ninja: build stopped: subcommand failed.

build.log

wally-mageia commented 3 years ago

See https://github.com/gabime/spdlog/issues/1955#issuecomment-860676872 for a fix.

For me libfmt 8.0.0 causes a test failure:

# /usr/bin/ctest --output-on-failure --force-new-ctest-process
Test project /builddir/build/BUILD/spdlog-1.8.5/build
    Start 1: spdlog-utests
1/1 Test #1: spdlog-utests ....................***Failed    4.73 sec

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
spdlog-utests is a Catch v2.8.0 host application.
Run with -? for options

-------------------------------------------------------------------------------
to_hex_different_size_per_line
-------------------------------------------------------------------------------
../tests/test_misc.cpp:202
...............................................................................

../tests/test_misc.cpp:217: FAILED:
  REQUIRE( ends_with(oss.str(), "0000: 090A0B410C4B  ...A.K" + std::string(spdlog::details::os::default_eol) + "0006: FFFF          .." + std::string(spdlog::details::os::default_eol)) )
with expansion:
  false

[2021-06-22 17:46:38.459] [test] [trace] Test stdout_st
[2021-06-22 17:46:38.459] [test] [debug] Test stdout_mt
[2021-06-22 17:46:38.459] [test] [info] Test stderr_st
[2021-06-22 17:46:38.459] [test] [info] Test stderr_mt
[2021-06-22 17:46:38.459] [test] [warning] Test stderr_mt
[2021-06-22 17:46:38.459] [test] [error] Test stderr_mt
[2021-06-22 17:46:38.459] [test] [critical] Test stderr_mt
[2021-06-22 17:46:38.460] [test] [info] Test stdout_color_st
[2021-06-22 17:46:38.460] [test] [trace] Test stdout_color_mt
[2021-06-22 17:46:38.460] [test] [debug] Test stderr_color_st
[2021-06-22 17:46:38.460] [test] [info] Test stderr_color_mt
[2021-06-22 17:46:38.460] [test] [warning] Test stderr_color_mt
[2021-06-22 17:46:38.460] [test] [error] Test stderr_color_mt
[2021-06-22 17:46:38.460] [test] [critical] Test stderr_color_mt
[*** LOG ERROR #0001 ***] [2021-06-22 17:46:39] [test-error] {argument not found}
===============================================================================
test cases: 145 | 144 passed | 1 failed
assertions: 492 | 491 passed | 1 failed

0% tests passed, 1 tests failed out of 1

Total Test time (real) =   4.74 sec

The following tests FAILED:
      1 - spdlog-utests (Failed)
Errors while running CTest
devurandom commented 3 years ago

Is this a duplicate of https://github.com/gabime/spdlog/issues/1941?

Evangel63 commented 3 years ago

Compile time format string checking also causes errors around fmt::format_to in spdlog::logger::log_. The error can be "fixed" by converting it to a runtime format checking with fmt::runtime. This only occurs when there's a format specifier in the string, if you just have string constants, then there is no error. This also occurs if you wrap your format string with FMT_STRING, or convert to a compile string with the _cf literal.

/extern/spdlog/include/spdlog/logger.h: In instantiation of ‘void spdlog::logger::log_(spdlog::source_loc, spdlog::level::level_enum, const FormatString&, const Args& ...) [with FormatString = fmt::v8::basic_string_view<char>; Args = {std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >}]’:
/extern/spdlog/include/spdlog/logger.h:87:13:   required from ‘void spdlog::logger::log(spdlog::source_loc, spdlog::level::level_enum, spdlog::string_view_t, const Args& ...) [with Args = {std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >}; spdlog::string_view_t = fmt::v8::basic_string_view<char>]’
/extern/spdlog/include/spdlog/logger.h:340:27: error: ‘fmt’ is not a constant expression
  316 |             fmt::format_to(buf, fmt, std::forward<Args>(args)...);
      |             ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~

If you use FMT_COMPILE, you get an error that looks like

/extern/spdlog/include/spdlog/spdlog.h:241:137: error: no matching function for call to ‘spdlog::logger::log(spdlog::source_loc, spdlog::level::level_enum, some_fn(const std::filesystem::__cxx11::path&)::<lambda()>::FMT_COMPILE_STRING, std::string)’
eklitzke commented 3 years ago

I made #1976 which fixes some of the build errors, but not everything so I closed it. At the minimum some things with fmt::pad and memory writers also need to be changed.

eklitzke commented 3 years ago

Is this a duplicate of #1941?

Yes, same issue.

gabime commented 3 years ago

Fixed in latest commit. But I get lots of warning C4996: 'fmt::v8::format_to': was declared deprecated

@vitaut What's the recommended replacement to format_to ? Currently spdlog use it as follows:

memory_buf_t buf;
fmt::format_to(buf, fmt, std::forward<Args>(args)...);
details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
vitaut commented 3 years ago

Only format_to that takes a buffer is deprecated, you can still pass an iterator:

fmt::format_to(std::back_inserter(buf), fmt, std::forward<Args>(args)...);
gabime commented 3 years ago

Fixed. Thanks @vitaut

Now spdlog ships with fmt v8.0 by default!

candrews commented 3 years ago

Now spdlog ships with fmt v8.0 by default!

:partying_face: I'm looking forward to a new release version!

lgbaldoni commented 3 years ago

I applied https://github.com/gabime/spdlog/commit/8bf718671a9eac5517c27a5ffe72089b7f426d8c in part (only the patch to src/fmt.cpp) and v7 headers seem to leak even with -DSPDLOG_FMT_EXTERNAL=ON.

Perhaps I misunderstand how that switch is supposed to work, but I was under the impression the bundled fmt headers would be completely ignored in favour of the system ones.

gabime commented 3 years ago

You need to take latest fmt commit, since it was fixed by fmt after the v8 release.

candrews commented 3 years ago

@gabime can you please make a new release of spdlog?

gabime commented 3 years ago

It is not ready yet. There are compilation problems with cpp 17/20 and with utf support in windows.

gabime commented 3 years ago

need to fix #1978

bbolli commented 3 years ago

There's already a fmt v8.0.1 out...

xvitaly commented 3 years ago

Any progress on this? I cannot build spdlog for Fedora Rawhide.

lgbaldoni commented 3 years ago

@xvitaly for what is worth, these patches fix the problem on openSUSE Tumbleweed.

xvitaly commented 3 years ago

@lgbaldoni It works. Many thanks.

gabime commented 3 years ago

@vitaut Could you advice on how to use FMT_COMPILE in spdlog? I am having trouble enabling it. For example, the following (with clang 13, c++20)

spdlog::info(FMT_COMPILE("should not compile ? {:d}"), "SDFSDF");

gives me:

/home/gabi/spdlog/include/spdlog/logger.h:95:9: error: no matching member function for call to 'log'
        log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
        ^~~
/home/gabi/spdlog/include/spdlog/logger.h:113:9: note: in instantiation of function template specialization 'spdlog::logger::log<FMT_COMPILE_STRING, char const (&)[7]>' requested here
        log(level::info, fmt, std::forward<Args>(args)...);
        ^
/home/gabi/spdlog/include/spdlog/spdlog.h:157:27: note: in instantiation of function template specialization 'spdlog::logger::info<FMT_COMPILE_STRING, char const (&)[7]>' requested here
    default_logger_raw()->info(fmt, std::forward<Args>(args)...);
                          ^
/home/gabi/spdlog/example/example.cpp:34:13: note: in instantiation of function template specialization 'spdlog::info<FMT_COMPILE_STRING, char const (&)[7]>' requested here
    spdlog::info(FMT_COMPILE("should not compile ? {:d}"), "SDFSDF");
            ^
/home/gabi/spdlog/include/spdlog/logger.h:87:10: note: candidate function template not viable: no known conversion from 'const FMT_COMPILE_STRING' to 'spdlog::string_view_t' (aka 'basic_string_view<char>') for 3rd argument
    void log(source_loc loc, level::level_enum lvl, string_view_t fmt, Args &&...args)
         ^
/home/gabi/spdlog/include/spdlog/logger.h:148:10: note: candidate function not viable: no known conversion from 'spdlog::source_loc' to 'log_clock::time_point' (aka 'time_point<std::chrono::system_clock, duration<long, ratio<1, 1000000000>>>') for 1st argument
    void log(log_clock::time_point log_time, source_loc loc, level::level_enum lvl, string_view_t msg)
         ^
/home/gabi/spdlog/include/spdlog/logger.h:80:10: note: candidate template ignored: requirement 'fmt::is_compile_string<FMT_COMPILE_STRING>::value' was not satisfied [with FormatString = FMT_COMPILE_STRING]
    void log(source_loc loc, level::level_enum lvl, const FormatString &fmt, Args &&...args)
         ^
/home/gabi/spdlog/include/spdlog/logger.h:183:10: note: candidate function template not viable: requires 3 arguments, but 4 were provided
    void log(source_loc loc, level::level_enum lvl, const T &msg)
         ^
/home/gabi/spdlog/include/spdlog/logger.h:161:10: note: candidate function not viable: requires 3 arguments, but 4 were provided
    void log(source_loc loc, level::level_enum lvl, string_view_t msg)
         ^
/home/gabi/spdlog/include/spdlog/logger.h:143:10: note: candidate function template not viable: requires 3 arguments, but 4 were provided
    void log(source_loc loc, level::level_enum lvl, const T &msg)
         ^
/home/gabi/spdlog/include/spdlog/logger.h:93:10: note: candidate function template not viable: no known conversion from 'spdlog::source_loc' to 'level::level_enum' for 1st argument
    void log(level::level_enum lvl, const FormatString &fmt, Args &&...args)
         ^
/home/gabi/spdlog/include/spdlog/logger.h:174:10: note: candidate function not viable: requires 2 arguments, but 4 were provided
    void log(level::level_enum lvl, string_view_t msg)
         ^
/home/gabi/spdlog/include/spdlog/logger.h:135:10: note: candidate function template not viable: requires 2 arguments, but 4 were provided
    void log(level::level_enum lvl, const T &msg)

and If I remove typename std::enable_if<fmt::is_compile_string<FormatString>::value, int>::type = 0 from logger.h it compiles fine but no compile time format error is raised by fmt.

vitaut commented 3 years ago

AFAICS removing enable_if works and gives you compile-time checks provided that you call a formatting function in info: https://godbolt.org/z/qEPv1zexz.

gabime commented 3 years ago

Unfortunately it doesn't work in spdlog context. I created a branch to reproduce: https://github.com/gabime/spdlog/blob/issue_1975/example/example.cpp

@vitaul Any help would be very appreciated.

vitaut commented 3 years ago

Is the repro supposed to give an error? It compiles with clang:

% clang++ --version
Apple clang version 12.0.5 (clang-1205.0.22.11)
Target: x86_64-apple-darwin20.5.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
% clang++ example/example.cpp -I include -std=c++20

Which compiler and options do you use?

vitaut commented 3 years ago

I see you mention clang 13 and c++20 in one of the previous comment which is kinda close to my setup.

gabime commented 3 years ago

Is the repro supposed to give an error? It compiles with clang:

I expected the line 

spdlog::info(FMT_COMPILE("Should not compile {:d}"), "hello");

to fail in compile time but it passed. I tried both gcc11 and clang, and got same result.

mjerabek commented 3 years ago

AFAICS the problem is in method log_, which converts the compile-time string to plain string_view:

memory_buf_t buf;
// faster than fmt::format_to(std::back_inserter(buf), fmt, std::forward<Args>(args)...);
fmt::detail::vformat_to(buf, fmt::string_view(fmt), fmt::make_format_args(args...), {});

I don't outright see which overload of which function to use, though.

gabime commented 3 years ago

which converts the compile-time string to plain string_view

I already tried to remove the conversion. Didn’t help. Got compiler errors.

vitaut commented 3 years ago

@mjerabek is correct, the reason why you don't get compile-time checks (or rather format string compilation because that's what FMT_COMPILE does) is conversion into string_view. If you want compile-time format string handling you should use fmt::format_to:

fmt::format_to(std::back_inserter(buf), fmt, std::forward<Args>(args)...);

instead of https://github.com/gabime/spdlog/blob/70d2832c0de306abc86ca06b751a7ed5ac0e525d/include/spdlog/logger.h#L342

You get compile errors because fmt/compile.h include is missing. Here's a simplified example: https://godbolt.org/z/3KvWoqW17 that uses format_to and has the correct include.

gabime commented 3 years ago

But then it won't compile (in c++20) without always wrapping with FMT_COMPILE: https://godbolt.org/z/35bvsq3cW

What I am trying to achieve it to provide the user the option to call info with or without FMT_COMPILE.

I tried here https://godbolt.org/z/1xhvrbexn to overload using typename std::enable_if<fmt::is_compile_string<S>::value, int>::type = 0,..

But that doesn't seem to work either. seems the format string is never marked as fmt::is_compile_string

As a side note,I thought that fmt enables compile-time format check by default in c++20, but it seems one need to wrap with FMT_COMPILE for the check to actually happen.

vitaut commented 3 years ago

What I am trying to achieve it to provide the user the option to call info with or without FMT_COMPILE.

In that case you'll need two overloads, one with format string compilation and one without (https://godbolt.org/z/Msc1cx3jq):

#include <fmt/compile.h>

template <
  typename S, typename... T,
  std::enable_if_t<!std::is_convertible_v<const S&, fmt::format_string<T...>>, int> = 0>
void info(const S& fmt, T&&... args) {
  auto buf = fmt::memory_buffer();
  fmt::format_to(std::back_inserter(buf), fmt, std::forward<T>(args)...);
}

template <typename... T>
void info(fmt::format_string<T...> fmt, T&&... args) {
  auto buf = fmt::memory_buffer();
  fmt::format_to(std::back_inserter(buf), fmt, std::forward<T>(args)...);
}
gabime commented 3 years ago

I might be missing something.. It doesn't compile if wrapped with FMT_COMPILE: https://godbolt.org/z/9qncEvhMc

vitaut commented 3 years ago

I messed up SFINAE in the example, should be fixed now (I updated the comment).

gabime commented 3 years ago

Great. Thanks @vitaut. Anyway, seems that under c++20 the format string get compiled anyway (even without wrapping with FMT_COMPILE). Probably by design?

vitaut commented 3 years ago

It will be validated at compile-time but still processed at runtime unless you wrap it in FMT_COMPILE. In the future some forms of compilation that don't result in code bloat might be enabled by default.

Ou7law007 commented 2 years ago

I'm getting error C4996: 'fmt::v9::detail::arg_mapper<context>::map': was declared deprecated after upgrading fmt to v 9.0.0 is this related?

DoooReyn commented 1 year ago

I'm getting error C4996: 'fmt::v9::detail::arg_mapper<context>::map': was declared deprecated after upgrading fmt to v 9.0.0 is this related?

I also ran into this issue. This problem is often encountered because it does not know how to convert to the target type. So, if you are trying to format a user-defined type, you need to refer to this. Or, just convert it to a common type.