Task sender

[dietmarkuehl]

No description provided.

[coveralls]

coverage: 94.212%. remained the same
when pulling 107abb3 on task-sender
into 1ac1fdf on main.

[Copilot]

Pull request overview

This PR updates beman::execution::task and related senders/schedulers to better expose completion signatures (including adding get_completion_signatures() static overloads), tightens allocator retrieval logic, and adds new example programs demonstrating task-as-sender / allocator propagation patterns.

Changes:

• Adjust task sender completion-signature exposure (rename to completion_signatures, add static get_completion_signatures()).
• Add static get_completion_signatures() to inline_scheduler::sender and task_scheduler::sender; refine allocator detection/construction in state.
• Add new examples (task-sender, alloc-1, odd-completions) and wire some into the examples CMake build.

Reviewed changes

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

Show a summary per file

File	Description
include/beman/task/detail/task.hpp	Updates task sender completion-signature declarations/queries.
include/beman/task/detail/task_scheduler.hpp	Adds static completion-signature query for the type-erased scheduler’s sender.
include/beman/task/detail/inline_scheduler.hpp	Adds static completion-signature query for inline scheduler sender.
include/beman/task/detail/state.hpp	Tightens allocator retrieval to require construction into allocator_type.
include/beman/task/detail/promise_type.hpp	Removes noexcept from await_transform(Sender&&).
examples/task-sender.cpp	New example demonstrating allocator propagation + deferred coroutine invocation.
examples/alloc-1.cpp	New allocator-focused example using deferred coroutine invocation.
examples/odd-completions.cpp	New example intended to exercise unusual completion paths.
examples/CMakeLists.txt	Adds task-sender and alloc-1 to the examples build list.

Comments suppressed due to low confidence (1)

examples/CMakeLists.txt:30

• examples/odd-completions.cpp was added in this PR but isn’t listed in ALL_EXAMPLES, so it won’t be built or run via ctest. If it’s intended to be a runnable example, add it to ALL_EXAMPLES (or document why it’s intentionally excluded).

set(TODO tls-scheduler into_optional issue-start-reschedules loop)

set(ALL_EXAMPLES
    task-sender
    task_scheduler
    rvalue-task
    customize
    issue-symmetric-transfer
    container
)

---

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[Copilot]

The global operator new/operator delete overloads here violate the required allocation contract: operator new must not return nullptr on allocation failure (it should throw std::bad_alloc), and operator delete must release the memory (currently it only logs and leaks). Consider mirroring the pattern used in examples/alloc.cpp (free in delete, and provide a sized delete overload as well).

Suggested change

	auto p = std::malloc(n);
	std::cout << "global new(" << n << ")->" << p << "\n";
	return p;
	}
	void operator delete(void* ptr) noexcept { std::cout << "global operator delete()" << ptr << "\n"; }
	void* p = std::malloc(n);
	if (!p) {
	throw std::bad_alloc();
	}
	std::cout << "global new(" << n << ")->" << p << "\n";
	return p;
	}
	void operator delete(void* ptr) noexcept {
	std::cout << "global operator delete()" << ptr << "\n";
	std::free(ptr);
	}
	void operator delete(void* ptr, std::size_t n) noexcept {
	std::cout << "global operator delete(" << n << ")->" << ptr << "\n";
	std::free(ptr);
	}

[Copilot]

This file uses std::pmr::polymorphic_allocator and std::pmr::memory_resource but doesn’t include <memory_resource>, which is the standard header that declares these types. Add the proper header(s) to avoid relying on transitive includes.

Suggested change

	#include <memory>
	#include <memory>
	#include <memory_resource>

[Copilot]

The global operator new/operator delete overloads here leak memory: operator delete only logs and never calls std::free (despite operator new using std::malloc). Also, operator new should throw std::bad_alloc instead of returning nullptr on failure. Align this with the implementation in examples/alloc.cpp (including a sized delete overload).

Suggested change

	auto p = std::malloc(n);
	std::cout << " global new(" << n << ")->" << p << "\n";
	return p;
	}
	void operator delete(void* ptr) noexcept { std::cout << " global operator delete()" << ptr << "\n"; }
	if (void* p = std::malloc(n)) {
	std::cout << " global new(" << n << ")->" << p << "\n";
	return p;
	}
	throw std::bad_alloc{};
	}
	void operator delete(void* ptr) noexcept {
	std::cout << " global operator delete(" << ptr << ")\n";
	std::free(ptr);
	}
	void operator delete(void* ptr, std::size_t n) noexcept {
	std::cout << " global sized operator delete(" << ptr << ", " << n << ")\n";
	std::free(ptr);
	}

[Copilot]

This example relies on std::pmr types (std::pmr::memory_resource, std::pmr::polymorphic_allocator) but does not include <memory_resource>. Add <memory_resource> (and any other direct headers) to ensure portable compilation.

[Copilot]

There is an early return at the start of main, so the subsequent ex::sync_wait(...) block is unreachable and will never run. Either remove the early return or restructure main so both examples execute as intended.

[Copilot]

This file header comment says examples/hello.cpp, but the filename is odd-completions.cpp. Update the header comment so it matches the actual file name (consistent with other examples like examples/odd-return.cpp).

Suggested change

	// examples/hello.cpp -*-C++-*-
	// examples/odd-completions.cpp -*-C++-*-

[Copilot]

The class documentation lists ex::set_stopped() as a possible completion, but the sender’s declared completion_signatures only contains set_value_t(). Either update the documentation or include set_stopped_t() in the declared completion signatures so they stay consistent.

[Copilot]

This file header comment says examples/hello.cpp, but the filename is task-sender.cpp. Please update the header comment to match the actual file name (consistent with other examples).

Suggested change

	// examples/hello.cpp -*-C++-*-
	// examples/task-sender.cpp -*-C++-*-

[Copilot]

This file header comment says examples/hello.cpp, but the filename is alloc-1.cpp. Please update the header comment to match the actual file name (consistent with other examples).

Suggested change

	// examples/hello.cpp -*-C++-*-
	// examples/alloc-1.cpp -*-C++-*-