* Fix formatting of nullptr with FMT_COMPILE and to_string
std::nullptr_t is implicitly convertible to string_view and const char*,
so compiled format strings and fmt::to_string treated nullptr as a null
C string: FMT_COMPILE("{}!") crashed and FMT_COMPILE("{}") and to_string
threw "string pointer is null". Format it as a pointer ("0x0") like the
runtime API does.
* Write nullptr as a pointer in detail::write
detail::write<Char>(out, nullptr) picked the const Char* overload, so
fmt::to_string(nullptr) and FMT_COMPILE("{}") threw "string pointer is
null". Add a nullptr_t overload that forwards to the const void* one.
nested_format_specs::write formatted the body of a padded value into a
temporary buffer using a context of the same type as the outer one. This
only works when the outer context writes to an appender, so FMT_COMPILE
and format_to with other output iterators failed to compile even when no
width was given.
Use a buffer context that takes arguments and locale from the outer
context when the outer context doesn't write to an appender.
Fixes#4949.
Drop the assertions that return from write_escaped_alternative before
reaching the advance_to call they were added to cover: the std::string
and char alternatives take the has_to_string_view and is_same_v<T, Char>
early returns, and expected<void, int> never calls the function at all.
All four are already checked in std-test.cc.
Merge format_unexpected into format_expected since both are guarded by
__cpp_lib_expected and the latter was a single assertion, and note that
std::unexpected has a formatter of its own so the adjacent unexpected(42)
checks are not duplicates.
Unify the duplicated trailing-zero computation in write_fixed and remove
the redundant guards around fill_n. Reduce the constexpr branch of
basic_memory_buffer::grow to a single construct loop that uses the
buffer's own allocator.
In tests, drop the MSVC version checks that FMT_USE_CONSTEVAL already
implies, replace a loop computing 2^-900 with the 0x1p-900 literal, and
report high_precision_long_double as skipped rather than passed when
long double is not an extended-precision type.
A named argument that arrives const-qualified was not recognized by
is_named_arg, silently dropping its name. This happens both when a
named argument is passed through an intermediate function returning
const T& (https://github.com/fmtlib/fmt/issues/4866) and in fmt's own
compiled format path, which passes arguments as const T&.
Make is_named_arg and is_static_named_arg see through top-level const so
the name is preserved instead of dropped.
The FMT_COMPILE("{}") format string takes a to_string fast path that
never runs the compiled field code the format_as fix (#4836) touched.
Use "[{}]" so the test actually goes through detail::field::format.
