Destructor ~Loop() may throw exception (violates C++ standard and guidelines)

[lyriccoder]

Problem description

The destructor of Loop is declared as noexcept(false) and directly calls Stop():

~Loop() noexcept(false) {
    this->Stop();
}

Inside Stop(), there is an unconditional rethrow of a stored exception:

if (curr_exce_) {
    std::rethrow_exception(curr_exce_);
}

This means the destructor may throw exceptions.

Why this is a problem

C++ Standard (ISO/IEC 14882:2017, 18.1, paragraph 7)
If a destructor invoked during stack unwinding exits with an exception, std::terminate() is called.

In other words, if an exception is already in flight and another one is thrown from the destructor, the program will unconditionally crash.

Coding guidelines

1. CERT C++ [ERR55-CPP]: Do not throw an exception from a destructor.
2. AUTOSAR C++14 [A15-5-1]: Destructors shall not exit with an exception.

The current implementation directly violates these rules.

Expected behavior

Destructors must not propagate exceptions. They should either:

• Catch and handle/log exceptions internally, or
• Guarantee Stop() is noexcept, or
• Require explicit Stop() invocation by the user before object destruction.

This aligns with the C++ standard, CERT, and AUTOSAR guidelines and prevents hard crashes due to std::terminate().

[trivialfis]

It's a real issue, but the fix is quite off ...

[lyriccoder]

It's a real issue, but the fix is quite off ...

can u suggest the new one? I will rewrite, just do not have the idea how to fix it in another way... @trivialfis Is the updated fix ok for you?

I added a boolean parameter from_destructor to the Stop() method to change behavior based on the caller:
Result Stop(bool from_destructor = false);

How it works:

1. Normal calls (Stop() or Stop(false)):

• Preserves original behavior
• Still throws exceptions via std::rethrow_exception()
• Maintains existing API contract for users

2. Destructor calls (Stop(true)):

• Converts exceptions to Result return values instead of throwing
• Uses try-catch to safely extract exception information
• Returns error details through the Result type