migrate core async abstractions from awaiters to senders

[wokron]

No public API changes. This refactors the internal async composition model to align the library more closely with sender/receiver concepts and prepare for future std::execution integration.

[Copilot]

Pull request overview

This PR refactors Condy’s internal async composition model from awaiter/finish-handle driven composition to a sender/receiver-style design, with coroutine integration via promise_type::await_transform, to better align with upcoming std::execution concepts.

Changes:

• Introduces sender types (OpSender, WhenAll/Any, ParallelAll/Any, link/hard_link, ranged variants) and their operation-state machinery.
• Migrates core completion handling from “invoker + extract_result()” to “receiver callback” in OpFinishHandle and Channel push/pop operations.
• Updates/removes tests to use the new model and adds a new sender-focused test file.

Reviewed changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
tests/test_senders.cpp	New end-to-end coverage for sender composition + channel usage.
tests/test_runtime.cpp	Disables runtime cancellation tests (TODO to re-enable).
tests/test_ring.cpp	Updates ring tests to receiver-based completion.
tests/test_parallel_finish_handle.cpp	Removes legacy parallel finish-handle tests.
tests/test_parallel_awaiter.cpp	Reworks test awaiters into sender-style “connect/start” operation states.
tests/test_op_finish_handle.cpp	Updates op finish-handle tests for receiver-style completion.
tests/test_awaiter_operations.cpp	Adjusts awaiter operation tests to new empty-range behavior and construction style.
include/condy/utils.hpp	Adds tuple→variant helper (tuple_at) used by when_any wrappers.
include/condy/senders.hpp	New sender type definitions for ops + composition primitives.
include/condy/sender_operations.hpp	New algorithms/operators (when_all/any, parallel, link, flags) + coroutine awaiter bridge.
include/condy/runtime.hpp	Removes invoker wiring from OpFinishHandleBase (completion now via receivers).
include/condy/op_states.hpp	New operation-state implementations for parallel/when/link composition.
include/condy/invoker.hpp	Adjusts Invoker/InvokerAdapter mechanics to support new completion flow.
include/condy/finish_handles.hpp	Migrates finish handles to deliver results directly to receivers + stop-token cancellation.
include/condy/coro.inl	Adds await_transform hook to await SenderLike types.
include/condy/context.hpp	Minor forward-decl cleanup (WorkInvoker).
include/condy/concepts.hpp	Replaces awaiter-like concept with sender-like concept.
include/condy/channel.hpp	Converts Channel push/pop awaiters into sender-based operations with stop-token cancellation.
include/condy/channel_legacy.hpp	Removes deprecated legacy channel header.
include/condy/awaiters.hpp	Re-exports awaiter names as sender aliases (compat surface).
include/condy/awaiter_operations.hpp	Makes “build/make op awaiter” return an op sender and routes composition through sender operations.

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[Copilot]

Two runtime cancellation tests have been fully commented out, leaving cross-task / cross-thread cancellation behavior untested. Please either re-enable/fix these tests as part of this refactor or add equivalent sender-based cancellation coverage before merging.

Suggested change

	// TODO: Re-enable these tests
	// TEST_CASE("test runtime - cancel from other task") {
	// condy::Runtime runtime(options);
	// auto cancel_task = [&](void *ptr) -> condy::Coro<void> {
	// runtime.cancel(ptr);
	// co_return;
	// };
	// auto func = [&]() -> condy::Coro<void> {
	// __kernel_timespec ts{
	// .tv_sec = 60ll * 60ll,
	// .tv_nsec = 0,
	// };
	// auto aw =
	// condy::detail::make_op_awaiter(io_uring_prep_timeout, &ts, 0, 0);
	// void *ptr = aw.get_handle();
	// auto t = condy::co_spawn(cancel_task(ptr));
	// co_await aw;
	// co_await t;
	// };
	// condy::co_spawn(runtime, func()).detach();
	// runtime.allow_exit();
	// runtime.run();
	// }
	// TEST_CASE("test runtime - cancel from other thread") {
	// condy::Runtime runtime(options);
	// std::atomic_bool r1_started = false;
	// void *ptr = nullptr;
	// auto notify_task = [&]() -> condy::Coro<void> {
	// r1_started = true;
	// r1_started.notify_one();
	// co_return;
	// };
	// auto func = [&]() -> condy::Coro<void> {
	// __kernel_timespec ts{
	// .tv_sec = 60ll * 60ll,
	// .tv_nsec = 0,
	// };
	// auto aw =
	// condy::detail::make_op_awaiter(io_uring_prep_timeout, &ts, 0, 0);
	// ptr = aw.get_handle();
	// auto t = condy::co_spawn(runtime, notify_task());
	// co_await aw;
	// co_await t;
	// };
	// condy::co_spawn(runtime, func()).detach();
	// std::thread t1([&]() {
	// runtime.allow_exit();
	// runtime.run();
	// });
	// r1_started.wait(false);
	// runtime.cancel(ptr);
	// t1.join();
	// }
	TEST_CASE("test runtime - cancel from other task") {
	condy::Runtime runtime(options);
	std::atomic_bool cancel_task_finished = false;
	std::atomic_bool func_finished = false;
	auto cancel_task = [&](void *ptr) -> condy::Coro<void> {
	runtime.cancel(ptr);
	cancel_task_finished = true;
	co_return;
	};
	auto func = [&]() -> condy::Coro<void> {
	__kernel_timespec ts{
	.tv_sec = 60ll * 60ll,
	.tv_nsec = 0,
	};
	auto aw =
	condy::detail::make_op_awaiter(io_uring_prep_timeout, &ts, 0, 0);
	void *ptr = aw.get_handle();
	auto t = condy::co_spawn(runtime, cancel_task(ptr));
	co_await aw;
	co_await t;
	func_finished = true;
	runtime.allow_exit();
	};
	condy::co_spawn(runtime, func()).detach();
	runtime.run();
	CHECK(cancel_task_finished.load());
	CHECK(func_finished.load());
	}
	TEST_CASE("test runtime - cancel from other thread") {
	condy::Runtime runtime(options);
	std::atomic_bool wait_ready = false;
	std::atomic_bool func_finished = false;
	void *ptr = nullptr;
	auto func = [&]() -> condy::Coro<void> {
	__kernel_timespec ts{
	.tv_sec = 60ll * 60ll,
	.tv_nsec = 0,
	};
	auto aw =
	condy::detail::make_op_awaiter(io_uring_prep_timeout, &ts, 0, 0);
	ptr = aw.get_handle();
	wait_ready = true;
	wait_ready.notify_one();
	co_await aw;
	func_finished = true;
	runtime.allow_exit();
	};
	condy::co_spawn(runtime, func()).detach();
	std::thread t1([&]() { runtime.run(); });
	wait_ready.wait(false);
	runtime.cancel(ptr);
	t1.join();
	CHECK(func_finished.load());
	}

[Copilot]

Pull request overview

Copilot reviewed 21 out of 21 changed files in this pull request and generated 9 comments.

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[Copilot]

Pull request overview

Copilot reviewed 21 out of 21 changed files in this pull request and generated 8 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.