tree f28bb30d2ae3a9498483babc817015976805c812
parent ca5b71a4559890a9768558ddea724782fb638bfa
author A. Jiang <de34@live.cn> 1749740021 +0800
committer GitHub <noreply@github.com> 1749740021 -0400
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[libc++] Fix constructing `bitset` from non-null-terminated arrays (#143691)

Unconditional evaluation of `char_traits<_CharT>::length(__str)` is problematic, because it causes
UB when `__str` points to a non-null-terminated array. We should only call `length` (currently, in
`basic_string_view`'s constructor) when `__n == npos` per [bitset.cons]/8.

Drive-by change: Reduction of conditional compilation, given that
- both `basic_string_view<_CharT>::size_type` and `basic_string<_CharT>::size_type` must be 
  `size_t`, and thus
- both `basic_string_view<_CharT>::npos` and `basic_string<_CharT>::npos` must be `size_t(-1)`.

For the type sameness in the standard wording, see:
- [string.view.template.general]
- [basic.string.general]
- [allocator.traits.types]/6
- [default.allocator.general]/1

Fixes #143684