[v2] terminal cancellation on async_execute() results in exit status 0 instead of 9

[pgit]

When calling terminate on a V2 process, the exit code on async_wait() is 0, but should be 9 (SIGKILL).

#include <boost/asio.hpp>
#include <boost/process/v2/process.hpp>
#include <iostream>

int main()
{
   boost::asio::io_context context;
   boost::process::v2::process child(context, "/usr/bin/sleep", {"10"});
   child.async_wait([](boost::system::error_code ec, int status){
      std::cout << status << std::endl;
   });
   child.terminate();  // prints 0 -- should be 9 (SIGKILL)
   // child.interrupt();  // prints 2 (SIGINT)
   // child.request_exit();  // prints 15 (SIGTERM)
   context.run();
}

This seems to be due to the implementation of terminate(), which -- unlike interrupt() and request_exit -- also calls wait:

process/include/boost/process/v2/detail/process_handle_signal.hpp

Line 239 in bd450f9

wait(exit_status, ec);

That wait() correctly retireves exit status 9, but before async_execute() completes, ::waitpid() is invoked again somewhere. If the wait() is removed, termiante() behaves correctly -- but I do not know if that has other implications.

[klemens-morgenstern]

Yes, terminate waits, so that the process is removed from the process table from the process table after terminate.

This should be caught by async_wait however, so you're reporting a bug.

[pgit]

Didn't verify, but your testcase is essentially the same as the sample above. Thank you for the quick reaction.