Bustache does not compile anymore with v11 #4470
Description
The bustache library does not compile with recent fmt versions.
I'm using bustache at commit 1a6d4422 (almost up-to-date).
Using fmt 10.2.1 the library compiles fine, with fmt 11.2.0 I get the following error:
In file included from /src/build/fmt-stage/include/fmt/format.h:41,
from /src/build/bustache-prefix/src/bustache/include/bustache/model.hpp:18,
from /src/build/bustache-prefix/src/bustache/include/bustache/render.hpp:10,
from /src/build/bustache-prefix/src/bustache/src/render.cpp:8:
/src/build/fmt-stage/include/fmt/base.h: In instantiation of ‘constexpr OutputIt fmt::v11::detail::copy(InputIt, InputIt, OutputIt) [with T = char; InputIt = const char*; OutputIt = std::back_insert_iterator<bustache::detail::output_buffer>; typename std::enable_if<(is_back_insert_iterator<OutputIt>::value && (! has_back_insert_iterator_container_append<OutputIt, InputIt>::value)), int>::type <anonymous> = 0]’:
/src/build/fmt-stage/include/fmt/format.h:1663:26: required from ‘constexpr OutputIt fmt::v11::detail::write_bytes(OutputIt, fmt::v11::string_view, const fmt::v11::format_specs&) [with Char = char; fmt::v11::align default_align = fmt::v11::align::left; OutputIt = std::back_insert_iterator<bustache::detail::output_buffer>; fmt::v11::string_view = fmt::v11::basic_string_view<char>]’
/src/build/fmt-stage/include/fmt/format.h:3425:33: required from ‘constexpr OutputIt fmt::v11::detail::write(OutputIt, T, const fmt::v11::format_specs&, locale_ref) [with Char = char; OutputIt = std::back_insert_iterator<bustache::detail::output_buffer>; T = bool; typename std::enable_if<std::is_same<T, bool>::value, int>::type <anonymous> = 0]’
/src/build/fmt-stage/include/fmt/format.h:3647:23: required from ‘constexpr decltype (ctx.out()) fmt::v11::detail::native_formatter<T, Char, TYPE>::format(const T&, FormatContext&) const [with FormatContext = fmt::v11::generic_context<std::back_insert_iterator<bustache::detail::output_buffer>, char>; T = bool; Char = char; fmt::v11::detail::type TYPE = fmt::v11::detail::type::bool_type; decltype (ctx.out()) = std::back_insert_iterator<bustache::detail::output_buffer>]’
/src/build/bustache-prefix/src/bustache/include/bustache/model.hpp:354:19: required from ‘void bustache::detail::print_fmt(const T&, bustache::output_handler, const char*) [with T = bool; bustache::output_handler = bustache::fn_ref<void(const char*, long unsigned int)>]’
/src/build/bustache-prefix/src/bustache/src/render.cpp:511:30: required from here
/src/build/fmt-stage/include/fmt/base.h:2054:5: error: ‘struct bustache::detail::output_buffer’ has no member named ‘insert’
2054 | c.insert(c.end(), begin, end);
| ~~^~~~~~
/src/build/fmt-stage/include/fmt/base.h:2054:14: error: ‘struct bustache::detail::output_buffer’ has no member named ‘end’
2054 | c.insert(c.end(), begin, end);
| ~~^~~
The bustache code uses a custom buffer/container that does not implement all "standard" methods, in particular no insert and no end. However it provides push_back and uses std::back_insert_iterator.
I may be wrong, but while such a custom container may be a corner case for fmt, I believe there is an issue in the selected copy implementation. std::back_insert_iterator seems to only require a push_back method, so fmt should probably not call insert/end.