PR 4286 causes segfault - please revert #4289
Description
Recent PR #4286 causes segfault.
The following code:
std::ostringstream Stream;
std::string Line = "";
Stream << fmt::format( "{}", fmt::styled( Line, fmt::fg( fmt::terminal_color::blue ) ) ) << "\n";segfaults with backtrace:
#0 0x000055555568bbf3 in fmt::v11::detail::buffer<char>::append<char> (this=0x0, begin=begin@entry=0x7fffffffb400 "\033[34m", end=end@entry=0x7fffffffb405 "")
at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/base.h:1797
#1 0x00005555556a69e3 in fmt::v11::detail::copy<char, char const*, fmt::v11::basic_appender<char>, 0> (begin=0x7fffffffb400 "\033[34m", end=0x7fffffffb405 "", out=...)
at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/base.h:2008
#2 0x00005555556984d2 in fmt::v11::formatter<fmt::v11::detail::styled_arg<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, char, void>::format<fmt::v11::context> (
this=0x7fffffffb480, arg=..., ctx=...) at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/color.h:574
#3 0x000055555568bcf1 in fmt::v11::detail::value<fmt::v11::context>::format_custom<fmt::v11::detail::styled_arg<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, fmt::v11::formatter<fmt::v11::detail::styled_arg<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, char, void> > (arg=0x7fffffffbaf0, parse_ctx=..., ctx=...)
at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/base.h:2240
#4 0x000055555570f6af in fmt::v11::basic_format_arg<fmt::v11::context>::handle::format (this=<optimized out>, parse_ctx=..., ctx=...)
at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/base.h:2444
#5 0x000055555570d9bd in fmt::v11::detail::default_arg_formatter<char>::operator() (this=0x7fffffffb608, h=...) at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/format.h:3488
#6 0x000055555570c767 in fmt::v11::basic_format_arg<fmt::v11::context>::visit<fmt::v11::detail::default_arg_formatter<char> > (this=this@entry=0x7fffffffb5c0, vis=...)
at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/base.h:2484
#7 0x000055555570a4b3 in fmt::v11::detail::vformat_to (buf=..., fmt=..., args=..., loc=...) at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/format-inl.h:1454
#8 0x000055555570a387 in fmt::v11::vformat[abi:cxx11](fmt::v11::basic_string_view<char>, fmt::v11::basic_format_args<fmt::v11::context>) (fmt=..., args=...)
at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/format-inl.h:1444
#9 0x000055555568269d in fmt::v11::format<fmt::v11::detail::styled_arg<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > (fmt=...)
at /home/user/_download/git_https_github.com__fmtlib_fmt.git/include/fmt/format.h:4186