Incorrectly assuming operator-> exists

[term-est]

Not necessarily.

Consider

		char a[] = "ab";
		char b[] = "cd";

		std::array bufs
		{
			const_buffer(a, 2),
			const_buffer(b, 2)
		};

		auto seq = bufs | std::views::transform([](const_buffer x) { return x; }); // sponsored by SG9

		static_assert(ConstBufferSequence<decltype(seq)>);

		// Fails in detail::linearize_buffers because transform_view's iterator
		// does not provide operator->
		std::ignore = detail::search_buffer_for_match(seq, match_delim{"bc"});

Example uses detail::API directly to reproduce the issue, but it can also be triggered through the public exposing API as well by passing a crafted weird_dyn_buffer of sorts:

	struct weird_dynamic_buffer
	{
		char a[2] = {'a', 'b'};
		char b[2] = {'c', 'd'};

		std::array<const_buffer, 2> readable
		{
			const_buffer(a, 2),
			const_buffer(b, 2)
		};

		char scratch[16]{};

		static constexpr auto id = [](const_buffer x) { return x; };

		using const_buffers_type = decltype(std::declval<std::array<const_buffer, 2> const&>() | std::views::transform(id)); // sponsored by SG9

		using mutable_buffers_type = mutable_buffer;

		std::size_t size() const noexcept { return 4; }

		std::size_t max_size() const noexcept { return 16; }

		std::size_t capacity() const noexcept { return 12; }

		const_buffers_type data() const { return readable | std::views::transform(id); }

		mutable_buffers_type prepare(std::size_t n) { return mutable_buffer(scratch, n); }

		void commit(std::size_t) {}

		void consume(std::size_t) {}
	};

	static_assert(DynamicBuffer<weird_dynamic_buffer>);

	task<void> fumo_fumo()
	{
		test::read_stream rs;

		weird_dynamic_buffer db;

		std::ignore = co_await read_until(rs, db, "bc");
	}

[cppalliance-bot]

An automated preview of the documentation is available at https://333.capy.prtest3.cppalliance.org/index.html

If more commits are pushed to the pull request, the docs will rebuild at the same URL.

2026-06-23 18:13:04 UTC

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.07%. Comparing base (9144290) to head (f1e5f90).

Additional details and impacted files

@@            Coverage Diff             @@
##           develop-2     #333   +/-   ##
==========================================
  Coverage      98.07%   98.07%           
==========================================
  Files            164      164           
  Lines           8774     8776    +2     
==========================================
+ Hits            8605     8607    +2     
  Misses           169      169           

Flag	Coverage Δ
linux	98.17% <ø> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
include/boost/capy/read_until.hpp	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

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[cppalliance-bot]

GCOVR code coverage report https://333.capy.prtest3.cppalliance.org/gcovr/index.html
LCOV code coverage report https://333.capy.prtest3.cppalliance.org/genhtml/index.html
Coverage Diff Report https://333.capy.prtest3.cppalliance.org/diff-report/index.html

Build time: 2026-06-23 18:32:00 UTC