pcntl not available in webserver environments causing errors

[wuuti]

If the RedisSimpleLock is used in webserver environments, it will probably most of the time produce a fatal error, because the pctnl extension is not compiled in to webserver's php modules.

It is used just once to register a shutdown function for the SIGINT in the constructor, which makes sense if we want to catch a cli execution and a pressed CTRL-C for example. But that prevents usage when the pcntl extension is not available.

Better

public function __construct($identifier, Client $client, $ttl = 10000, LoggerInterface $logger = null)
    {
        $this->identifier = $identifier;
        $this->client     = $client;
        $this->ttl        = $ttl;
        $this->logger     = $logger ?: new NullLogger;
        $this->id         = mt_rand();
        register_shutdown_function($closure = $this->releaseClosure());
        if (function_exists('pcntl_signal')) {
            pcntl_signal(SIGINT, $closure);
        } 
    }

[mathroc]

that’s true, however I would rather not silently ignore SIGINT on the cli. I would accept a PR with something similar to:

    public function __construct($identifier, Client $client, $ttl = 10000, LoggerInterface $logger = null, $ignoredSIGINTForSAPIs = [])
    {
        $this->identifier = $identifier;
        $this->client     = $client;
        $this->ttl        = $ttl;
        $this->logger     = $logger ?: new NullLogger;
        $this->id         = mt_rand();
        register_shutdown_function($closure = $this->releaseClosure());
        if (!in_array(php_sapi_name(), $ignoredSIGINTForSAPIs)) {
            pcntl_signal(SIGINT, $closure);
        } 
    }

so that you can explicitly say you don’t want to catch SIGINT when needed

[mathroc]

thank you @im-bryan for working on this