9db7144d0f
When compiling with libfmt-11.1.0 and newer the following compile errors occur:
In file included from ../src/decoder/DecoderPrint.cxx:23:
../src/client/Response.hxx: In instantiation of 'bool Response::Fmt(const S&, Args&& ...) [with S = decoder_plugin_print(Response&, const DecoderPlugin&)::<lambda()>::FMT_COMPILE_STRING; Args = {const char* const&}]':
../src/decoder/DecoderPrint.cxx:38:7: required from here
38 | r.Fmt(FMT_STRING("plugin: {}\n"), plugin.name);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../src/client/Response.hxx:86:28: error: cannot convert 'const decoder_plugin_print(Response&, const DecoderPlugin&)::<lambda()>::FMT_COMPILE_STRING' to 'fmt::v11::string_view' {aka 'fmt::v11::basic_string_view<char>'}
86 | return VFmt(format_str,
| ~~~~^~~~~~~~~~~~
87 | fmt::make_format_args(args...));
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../src/client/Response.hxx:81:36: note: initializing argument 1 of 'bool Response::VFmt(fmt::v11::string_view, fmt::v11::format_args)'
81 | bool VFmt(fmt::string_view format_str, fmt::format_args args) noexcept;
| ~~~~~~~~~~~~~~~~~^~~~~~~~~~
../src/client/Response.hxx: In instantiation of 'bool Response::Fmt(const S&, Args&& ...) [with S = decoder_plugin_print(Response&, const DecoderPlugin&)::<lambda()>::FMT_COMPILE_STRING; Args = {const char* const&}]':
The error is due to the use of FMT_STRING. The libfmt team shared the following:
The correct way of using FMT_STRING is to wrap a format string when passing to a
function with compile-time checks (i.e. that takes format_string) as documented
in https://fmt.dev/11.1/api/#legacy-compile-time-checks.
Noting that FMT_STRING is a legacy API and has been superseded by consteval-based
API starting from version 8: https://github.com/fmtlib/fmt/releases/tag/8.0.0. It
looks like MPD is trying to emulate {fmt}'s old way of implementing compile-time
checks which was never properly documented because it was basically a hack. So the
correct fix is to switch to format_string and, possibly, remove usage of FMT_STRING.
The old way of doing compile-time checks (fmt::make_args_checked) was documented
in https://fmt.dev/7.1/api.html#argument-lists but it looks like MPD is not using
that API so the problematic uses of FMT_STRING have no effect and can just be removed.
The FMT_STRING has been removed in this change based on the fmt-7.1 API and now MPD is
successfully compile against the current libfmt-11.1.0 which highlighted the issue that
had been present in the codebase as it is now triggering the error, is legacy and was
not using the API for which FMT_STRING was aligned with.
Music Player Daemon
A daemon for playing music of various formats. Music is played through the server's audio device. The daemon stores info about all available music, and this info can be easily searched and retrieved. Player control, info retrieval, and playlist management can all be managed remotely.
For basic installation instructions read the manual.
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MPD is released under the GNU General Public License version 2, which is distributed in the COPYING file.