Including spdlog after fmt throws an error: no member named 'basic_runtime' in namespace 'fmt', but the reverse is fine

[GavinRay97]

Reproduction:

project(example)
cmake_minimum_required(VERSION 3.20)

Include(FetchContent)
FetchContent_Declare(
    fmt
    GIT_REPOSITORY https://github.com/fmtlib/fmt
    GIT_TAG        master
)
FetchContent_MakeAvailable(fmt)
FetchContent_Declare(
    spdlog
    GIT_REPOSITORY https://github.com/gabime/spdlog
    GIT_TAG        v1.11.0
)
FetchContent_MakeAvailable(spdlog)

file(GLOB_RECURSE SOURCES "src/*.cpp")
add_executable(example ${SOURCES})
target_link_libraries(example
    PRIVATE
        fmt::fmt
        spdlog::spdlog
)

#include <fmt/format.h>
#include <spdlog/spdlog.h> // Error here

int main() { return 0; }

[tt4g]

To use an external fmt library, you must define CMake variable SPDLOG_FMT_EXTERNAL (or SPDLOG_FMT_EXTERNAL_HQ).

spdlog/CMakeLists.txt

Lines 88 to 89 in 654dbc5

	option(SPDLOG_FMT_EXTERNAL "Use external fmt library instead of bundled" OFF)
	option(SPDLOG_FMT_EXTERNAL_HO "Use external fmt header-only library instead of bundled" OFF)

[GavinRay97]

Ah whoops, my apologies, sorry for cluttering the issues!

EDIT: This still appears to be an issue even after setting the CMake variable, I have done:

set(SPDLOG_FMT_EXTERNAL ON CACHE BOOL "Use external fmt library" FORCE)

# ... fetchcontent stuff
FetchContent_Declare(
    spdlog
    GIT_REPOSITORY https://github.com/gabime/spdlog
    GIT_TAG        v1.11.0
)
FetchContent_MakeAvailable(spdlog)

[build] [7/9] Building CXX object _deps/spdlog-build/CMakeFiles/spdlog.dir/src/spdlog.cpp.o
[build] FAILED: _deps/spdlog-build/CMakeFiles/spdlog.dir/src/spdlog.cpp.o 
[build] ccache /home/user/projects/llvm-project/build/bin/clang++ -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL -I/home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include -I/home/user/projects/bustub-cpp-v2/build/sanitize/_deps/fmt-src/include -g -fcolor-diagnostics -std=c++2b -MD -MT _deps/spdlog-build/CMakeFiles/spdlog.dir/src/spdlog.cpp.o -MF _deps/spdlog-build/CMakeFiles/spdlog.dir/src/spdlog.cpp.o.d -o _deps/spdlog-build/CMakeFiles/spdlog.dir/src/spdlog.cpp.o -c /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/src/spdlog.cpp
[build] In file included from /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/src/spdlog.cpp:8:
[build] In file included from /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/spdlog-inl.h:7:
[build] In file included from /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/spdlog.h:12:
[build] /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/common.h:168:111: error: no member named 'basic_runtime' in namespace 'fmt'
[build]           std::is_convertible<T, fmt::basic_string_view<Char>>::value || std::is_same<remove_cvref_t<T>, fmt::basic_runtime<Char>>::value>
[build]                                                                                                          ~~~~~^
[build] /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/common.h:168:125: error: 'Char' does not refer to a value
[build]           std::is_convertible<T, fmt::basic_string_view<Char>>::value || std::is_same<remove_cvref_t<T>, fmt::basic_runtime<Char>>::value>
[build]                                                                                                                             ^
[build] /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/common.h:165:25: note: declared here
[build] template<class T, class Char = char>
[build]                         ^
[build] /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/common.h:168:130: error: expected '(' for function-style cast or type construction
[build]           std::is_convertible<T, fmt::basic_string_view<Char>>::value || std::is_same<remove_cvref_t<T>, fmt::basic_runtime<Char>>::value>
[build]                                                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
[build] /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/common.h:168:133: error: expected class name
[build]           std::is_convertible<T, fmt::basic_string_view<Char>>::value || std::is_same<remove_cvref_t<T>, fmt::basic_runtime<Char>>::value>
[build]                                                                                                                                     ^
[build] /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/common.h:188:123: error: no member named 'value' in 'spdlog::is_convertible_to_basic_format_string<const fmt::basic_string_view<char> &>'
[build] struct is_convertible_to_any_format_string : std::integral_constant<bool, is_convertible_to_basic_format_string<T, char>::value ||
[build]                                                                           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
[build] /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/logger.h:106:48: note: in instantiation of template class 'spdlog::is_convertible_to_any_format_string<const fmt::basic_string_view<char> &>' requested here
[build]     template<class T, typename std::enable_if<!is_convertible_to_any_format_string<const T &>::value, int>::type = 0>
[build]                                                ^
[build] /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/logger.h:107:10: note: while substituting prior template arguments into non-type template parameter [with T = string_view_t]
[build]     void log(source_loc loc, level::level_enum lvl, const T &msg)
[build]          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[build] /home/user/projects/bustub-cpp-v2/build/sanitize/_deps/spdlog-src/include/spdlog/logger.h:140:9: note: while substituting deduced template arguments into function template 'log' [with T = string_view_t, $1 = (no value)]
[build]         log(source_loc{}, lvl, msg);
[build]         ^
[build] 5 errors generated.

[tt4g]

The fmt bundled with spdlog v1.11.0 is version 9.1.0.
This version was released on 2022-08-28 (https://github.com/fmtlib/fmt/releases/tag/9.1.0).

If the latest fmt source code has incompatible changes, spdlog is not guaranteed to work.

EDIT: fmt::basic_runtime has been removed from fmtlib/fmt@3a5e19f (this change not released yet).

[GavinRay97]

Ahh okay, thank you!