add some noexcept

[wokron]

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[Copilot]

Pull request overview

This pull request adds noexcept specifiers to numerous functions across the runtime and ring classes, fundamentally changing the error handling strategy from exceptions to assertions. The changes affect core runtime operations, io_uring wrapper functions, and synchronization helpers.

Changes:

• Added noexcept to ~30 functions in runtime.hpp, ring.hpp, and helper functions
• Converted exception-throwing error handling to assertions in critical paths
• Removed test case that verified exception behavior for deprecated fd_accepter feature
• Removed try-catch block from sync_wait that handled runtime.run() exceptions

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
tests/test_fd_table.cpp	Removed test case that verified std::logic_error throwing behavior for deprecated fd_accepter feature
include/condy/sync_wait.hpp	Removed try-catch block around runtime.run() call, consistent with run() becoming noexcept
include/condy/runtime.hpp	Added noexcept to run(), schedule(), and other runtime methods; replaced exceptions with assertions and fprintf
include/condy/ring.hpp	Added noexcept to Ring, FdTable, BufferTable, and RingSettings methods; replaced throw with assertion in reap_completions_wait()

Comments suppressed due to low confidence (2)

include/condy/runtime.hpp:369

• The process_cqe_ function is now marked noexcept, but it calls handle->handle_cqe(cqe) on line 368, which can indirectly call user-provided callbacks (e.g., in MultiShotMixin::func_ and ZeroCopyMixin::free_func_) that may throw exceptions. If any of these user callbacks throw an exception, std::terminate will be called. This is a breaking change in behavior and should be carefully considered, especially since the MultiShotMixin pattern allows arbitrary user code to be executed during CQE processing.

    void process_cqe_(io_uring_cqe *cqe) noexcept {
        auto *data_raw = io_uring_cqe_get_data(cqe);
        auto [data, type] = decode_work(data_raw);

        if (type == WorkType::Ignore) {
            // No-op
            assert(cqe->res != -EINVAL); // If EINVAL, something is wrong
        } else if (type == WorkType::SendFd) {
            auto &fd_table = ring_.fd_table();
            if (fd_table.fd_accepter_ == nullptr) [[unlikely]] {
                std::fprintf(stderr, "[Deprecated Warning] Received a file "
                                     "descriptor but no accepter is set.");
            }
            uint64_t payload = reinterpret_cast<uint64_t>(data) >> 3;
            if (payload == 0) { // Auto-allocate
                fd_table.fd_accepter_(cqe->res);
            } else {
                int target_fd = static_cast<int>(payload - 1);
                fd_table.fd_accepter_(target_fd);
            }
        } else if (type == WorkType::Schedule) {
            if (data == nullptr) {
                assert(cqe->res == 0);
                pending_works_--;
            } else {
                auto *work = static_cast<WorkInvoker *>(data);
                tsan_acquire(data);
                local_queue_.push_back(work);
            }
        } else if (type == WorkType::Common) {
            auto *handle = static_cast<OpFinishHandleBase *>(data);
            auto action = handle->handle_cqe(cqe);
            if (action.op_finish) {

include/condy/runtime.hpp:356

• The warning message is printed when fd_accepter_ is nullptr, but then the code continues to call fd_accepter_ unconditionally on lines 352 and 355, which will cause a null pointer dereference. This check should either return early after printing the warning, or the subsequent calls to fd_accepter_ should be guarded with another nullptr check.

            if (fd_table.fd_accepter_ == nullptr) [[unlikely]] {
                std::fprintf(stderr, "[Deprecated Warning] Received a file "
                                     "descriptor but no accepter is set.");
            }
            uint64_t payload = reinterpret_cast<uint64_t>(data) >> 3;
            if (payload == 0) { // Auto-allocate
                fd_table.fd_accepter_(cqe->res);
            } else {
                int target_fd = static_cast<int>(payload - 1);
                fd_table.fd_accepter_(target_fd);
            }

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