This PR was merged into the 5.2-dev branch.Discussion----------[Console] Rework the signal integration| Q             | A| ------------- | ---| Branch?       | master| Bug fix?      | no| New feature?  | yes| Deprecations? | no| Tickets       | refs#33729| License       | MIT| Doc PR        |I updated the code to have a better design and DX:* `SignalRegistry::$handlingSignals` is gone. This was a temporary data store to  bind signal to symfony event. This does not belong to the `SignalRegistry`. It  has been replaced by `Application::$signalsToDispatchEvent`. A method has been  added to edit this list `Application::setSignalsToDispatchEvent()`* The default value for `Application::$signalsToDispatchEvent` is `SIGINT,  SIGTERM, SIGUSR1, SIGUSR2`. Theses defaults seems good enough for most of  application. for recall:    * `SIGINT`: CTRL+C    * `SIGTERM`: `kill PID`, this is what occurs when stopping a process with SystemD, upstart & co    * `SIGUSR1` and `SIGUSR2`: Signal for user space* `Application::setSignalRegistry()` is gone. Now the Application always owns a  signal registry. Since it's a CLI, it's legit to always have support for  signals. A method has been added for convenience, and to register signal  handler manually from the command:    ```php        $application->getSignalRegistry()->register(SIGINT, function ($signal) {            dump("Signal ($signal) caught");        });    ```* The interface `SignalableCommandInterface` has been added. When a command  implements this interface, the command is automatically called when a  registered signal has been caughtA note about the BC:* If one register an handler before the Symfony ones, the Signal Registry keeps   existing registered handlers. The BC is kept ✅* If one register an handler after the Symfony ones, it overrides the Symfony  behavior. Since the feature is new. the BC is kept ✅---So now, If one want to listen a signal, they have few options depending on the context:* A global action is common to all commands (such as logging, enabling a  profiler (👋 blackfire.io)): Use a listener. With autoconfigure, the following  code is enough:    ```php    class SignalSubscriber implements EventSubscriberInterface    {        private $logger;        public function __construct(LoggerInterface $logger = null)        {            $this->logger = $logger ?: new NullLogger();        }        public function handleSignal(ConsoleSignalEvent $event)        {            $signal = $event->getHandlingSignal();            $this->logger->debug('The application has been signaled', [                'signal' => $signal,            ]);        }        public static function getSubscribedEvents()        {            return [                ConsoleEvents::SIGNAL => 'handleSignal',            ];        }    }    ```* The command should react to a signal: Implements the interface:    ```php    class SignalCommand extends Command implements SignalableCommandInterface    {        protected static $defaultName = 'signal';        private $shouldStop = false;        protected function execute(InputInterface $input, OutputInterface $output): int        {            $output->writeln('hello, I am '. getmypid());            for ($i=0; $i < 60; $i++) {                if ($this->shouldStop) {                    break;                }                $output->write('.');                sleep(1);            }            $output->writeln('');            $output->writeln('bye');            return 0;        }        public function handleSignal(int $signal)        {            dump([__METHOD__, $signal]);            $this->shouldStop = true;        }        public function getSubscribedSignals(): array        {            return [SIGINT];        }    }    ```* The command should react differently to many event and/or one wants a full control on name of the method called    ```php    class SignalCommand extends Command    {        protected static $defaultName = 'signal';        private $shouldStop = false;        protected function execute(InputInterface $input, OutputInterface $output): int        {            $this->getApplication()->getSignalRegistry()->register(SIGINT, [$this, 'stop']);            $this->getApplication()->getSignalRegistry()->register(SIGUSR1, [$this, 'enableBlackfire']);            $output->writeln('hello, I am '. getmypid());            for ($i=0; $i < 60; $i++) {                if ($this->shouldStop) {                    break;                }                $output->write('.');                sleep(1);            }            $output->writeln('');            $output->writeln('bye');            return 0;        }        public function stop()        {            $this->shouldStop = true;        }        public function enableBlackfire()        {            // ...        }    }    ```ping@marieCommits-------df57119 [Console] Rework the signal integration