Add a way to reset GSDK in cppsdk

[artkuy]

This PR modifies the cppsdk to add a way to stop GSDK before calling exit() or exiting main.

Allows user to control lifetime of GSDK, needed to prevent allocations from happening after custom memory allocator has been destroyed. This is done by GSDK::logMessage from the heartbeat thread.

[Dimitris Gkanatsios (dgkanatsios)]

hey artkuy thanks for the contribution. This looks like a change in the public GSDK API, which makes it hard to accept since we'll have to change all other implementations as well.

Can you shed more light on the issue your PR tries to solve? Maybe there's something else we can do on the C++ side to prevent this issue from happening.

[artkuy]

Hi Dimitris Gkanatsios (@dgkanatsios), in our use case it's a problem that static std::unique_ptr<GSDKInternal> m_instance; is static. Since it won't deconstruct itself until after main is exited or exit() is called. When new and delete are overridden and a custom allocator is used it is possible for an exit crash to occur in std::locale from GSDK::logMessage called from the heartbeat thread. Because GSDK is destroyed after the custom allocator.

We need a way to control the lifetime of GSDK and stop it before we destroy our memory allocator.

[Dimitris Gkanatsios (dgkanatsios)]

thank you for the explanation - I have asked C++ experts in our team to take a look at it.
Quick question: you mention the crash can be caused by the logMessage method - is there any chance we can change that method to prevent the crash?

[artkuy]

Perhaps, but this seems rather prone to future issues as it's any dynamic allocation that would cause crashing. So any future addition to the project could quickly break it again.

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[Copilot]

Pull request overview

Adds explicit GSDK lifecycle teardown to stop background work before application shutdown.

Changes:

• Adds the public GSDK::reset() API.
• Stops and joins the heartbeat thread before resetting internal state.
• Guards thread joining with joinable().

Reviewed changes

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

File	Description
cpp/cppsdk/gsdk.h	Declares and documents reset().
cpp/cppsdk/gsdk.cpp	Implements heartbeat shutdown and instance reset.

Suppressed comments (2)

cpp/cppsdk/gsdk.cpp:522

• reset() can block for the full agent-provided heartbeat interval (which is not capped) because the heartbeat thread may be waiting on m_signalHeartbeatEvent. When that wait eventually expires, the loop also sends one more heartbeat before observing the false flag. Signal the event during reset and re-check m_keepHeartbeatRunning immediately after Wait() so teardown wakes promptly without issuing another request.

                GSDKInternal::get().m_keepHeartbeatRunning = false;

                if (GSDKInternal::get().m_heartbeatThread.joinable())
                {
                    GSDKInternal::get().m_heartbeatThread.join();

cpp/cppsdk/gsdk.cpp:525

• A shutdown callback is executed by m_shutdownThread; if that callback calls this new teardown API before exiting, resetting the instance destroys the std::future for the currently executing async task. The future destructor waits for that task to finish, so the callback deadlocks waiting on itself. Keep callback-task ownership outside GSDKInternal, or defer instance destruction when reset is invoked from the callback thread.

                GSDKInternal::m_instance.reset();