From: Stuart Henderson <stu@spacehopper.org>
Subject: Re: Unbreak mongodb-4.4.29 with libcxx19
To: Rafael Sadowski <rafael@sizeofvoid.org>
Cc: The OpenBSD ports mailing-list <ports@openbsd.org>
Date: Sat, 27 Sep 2025 14:31:13 +0100

On 2025/09/27 09:08, Rafael Sadowski wrote:
> Diff to unbreak mongodb44.
> 
> For details read patch-src_third_party_fmt_dist_include_fmt_format_h
> 
> OK?

Please would you also bump REVISION for clarity (pkg_add will find it
anyway because of the libc++ bump, but I think it's better that way) and
remove rather than just comment-out BROKEN.

Ok :)


> Index: Makefile
> ===================================================================
> RCS file: /cvs/ports/databases/mongodb/44/Makefile,v
> diff -u -p -u -p -r1.25 Makefile
> --- Makefile	2 Sep 2025 12:13:35 -0000	1.25
> +++ Makefile	27 Sep 2025 07:06:13 -0000
> @@ -1,6 +1,6 @@
>  PORTROACH =	limitw:1,even
>  
> -BROKEN =	fails with newer libc++
> +#BROKEN =	fails with newer libc++
>  
>  V =		4.4.29
>  REVISION =	5
> Index: patches/patch-src_third_party_fmt_dist_include_fmt_format_h
> ===================================================================
> RCS file: patches/patch-src_third_party_fmt_dist_include_fmt_format_h
> diff -N patches/patch-src_third_party_fmt_dist_include_fmt_format_h
> --- /dev/null	1 Jan 1970 00:00:00 -0000
> +++ patches/patch-src_third_party_fmt_dist_include_fmt_format_h	27 Sep 2025 07:06:13 -0000
> @@ -0,0 +1,113 @@
> +"The base template for std::char_traits has been removed in LLVM 19. If you are
> +using std::char_traits with types other than char, wchar_t, char8_t, char16_t,
> +char32_t or a custom character type for which you specialized std::char_traits,
> +your code will stop working. The Standard does not mandate that a base template
> +is provided, and such a base template is bound to be incorrect for some types,
> +which could currently cause unexpected behavior while going undetected."
> +
> +https://releases.llvm.org/19.1.0/projects/libcxx/docs/ReleaseNotes.htm
> +
> +This affects fmt 6.x used by MongoDB 4.4, which uses fmt::char8_t with
> +std::char_traits.
> +
> +Add a minimal std::char_traits impl for fmt::char8_t based on the
> +libc++ reference implementation for char traits:
> +https://github.com/llvm/llvm-project/blob/main/libcxx/include/__string/char_traits.h#L46
> +
> +This is a minimal fix to fix mongodb44 with libcxx19 from base.
> +
> +Index: src/third_party/fmt/dist/include/fmt/format.h
> +--- src/third_party/fmt/dist/include/fmt/format.h.orig
> ++++ src/third_party/fmt/dist/include/fmt/format.h
> +@@ -43,6 +43,91 @@
> + #include <memory>
> + #include <stdexcept>
> + 
> ++#if defined(_LIBCPP_VERSION) && _LIBCPP_VERSION >= 190000
> ++namespace std {
> ++template <>
> ++struct char_traits<fmt::char8_t> {
> ++    using char_type = fmt::char8_t;
> ++    using int_type = unsigned int;
> ++    using off_type = streamoff;
> ++    using pos_type = streampos;
> ++    using state_type = mbstate_t;
> ++
> ++    static constexpr void assign(char_type& c1, const char_type& c2) noexcept {
> ++        c1 = c2;
> ++    }
> ++
> ++    static constexpr bool eq(char_type c1, char_type c2) noexcept {
> ++        return c1 == c2;
> ++    }
> ++
> ++    static constexpr bool lt(char_type c1, char_type c2) noexcept {
> ++        return c1 < c2;
> ++    }
> ++
> ++    static constexpr int compare(const char_type* s1, const char_type* s2, size_t n) {
> ++        for (size_t i = 0; i < n; ++i) {
> ++            if (lt(s1[i], s2[i])) return -1;
> ++            if (lt(s2[i], s1[i])) return 1;
> ++        }
> ++        return 0;
> ++    }
> ++
> ++    static constexpr size_t length(const char_type* s) {
> ++        size_t len = 0;
> ++        while (!eq(s[len], char_type())) ++len;
> ++        return len;
> ++    }
> ++
> ++    static constexpr const char_type* find(const char_type* s, size_t n, const char_type& a) {
> ++        for (size_t i = 0; i < n; ++i) {
> ++            if (eq(s[i], a)) return s + i;
> ++        }
> ++        return nullptr;
> ++    }
> ++
> ++    static char_type* move(char_type* dest, const char_type* src, size_t n) {
> ++        if (dest < src) {
> ++            for (size_t i = 0; i < n; ++i) dest[i] = src[i];
> ++        } else if (src < dest) {
> ++            for (size_t i = n; i > 0; --i) dest[i-1] = src[i-1];
> ++        }
> ++        return dest;
> ++    }
> ++
> ++    static char_type* copy(char_type* dest, const char_type* src, size_t n) {
> ++        for (size_t i = 0; i < n; ++i) dest[i] = src[i];
> ++        return dest;
> ++    }
> ++
> ++    static char_type* assign(char_type* s, size_t n, char_type a) {
> ++        for (size_t i = 0; i < n; ++i) s[i] = a;
> ++        return s;
> ++    }
> ++
> ++    static constexpr int_type not_eof(int_type c) noexcept {
> ++        return eq_int_type(c, eof()) ? ~eof() : c;
> ++    }
> ++
> ++    static constexpr char_type to_char_type(int_type c) noexcept {
> ++        return char_type(c);
> ++    }
> ++
> ++    static constexpr int_type to_int_type(char_type c) noexcept {
> ++        return int_type(c);
> ++    }
> ++
> ++    static constexpr bool eq_int_type(int_type c1, int_type c2) noexcept {
> ++        return c1 == c2;
> ++    }
> ++
> ++    static constexpr int_type eof() noexcept {
> ++        return int_type(EOF);
> ++    }
> ++};
> ++}
> ++#endif
> ++
> + #ifdef __clang__
> + #  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
> + #else
>