Remove event priorities.

The whole concept of event priorities doesn’t make sense as a concept
and can’t even be trusted as an end user because you are relying on the
exact order of listeners. Priority also makes no sense in modern apps
where many events may be queued. Can be implemented as a synchronous
pipeline. Also removed halting events as this suffers from same problem
of relying on the exact order and implementation of your events,
depending on no handlers being queued, etc. Should use other pattern
when this is needed.

Author: taylorotwell

src/Illuminate/Contracts/Events/Dispatcher.php

@@ -9,10 +9,9 @@ interface Dispatcher
      *
      * @param  string|array  $events
      * @param  mixed  $listener
-     * @param  int  $priority
      * @return void
      */
-    public function listen($events, $listener, $priority = 0);
+    public function listen($events, $listener);
 
     /**
      * Determine if a given event has listeners.
@@ -39,15 +38,6 @@ public function push($event, $payload = []);
      */
     public function subscribe($subscriber);
 
-    /**
-     * Fire an event until the first non-null response is returned.
-     *
-     * @param  string  $event
-     * @param  array  $payload
-     * @return mixed
-     */
-    public function until($event, $payload = []);
-
     /**
      * Flush a set of pushed events.
      *
@@ -61,17 +51,9 @@ public function flush($event);
      *
      * @param  string|object  $event
      * @param  mixed  $payload
-     * @param  bool  $halt
      * @return array|null
      */
-    public function dispatch($event, $payload = [], $halt = false);
-
-    /**
-     * Get the event that is currently firing.
-     *
-     * @return string
-     */
-    public function dispatching();
+    public function dispatch($event, $payload = []);
 
     /**
      * Remove a set of listeners from the dispatcher.

src/Illuminate/Events/Dispatcher.php

@@ -34,20 +34,6 @@ class Dispatcher implements DispatcherContract
      */
     protected $wildcards = [];
 
-    /**
-     * The sorted event listeners.
-     *
-     * @var array
-     */
-    protected $sorted = [];
-
-    /**
-     * The event firing stack.
-     *
-     * @var array
-     */
-    protected $firing = [];
-
     /**
      * The queue resolver instance.
      *
@@ -71,18 +57,15 @@ public function __construct(ContainerContract $container = null)
      *
      * @param  string|array  $events
      * @param  mixed  $listener
-     * @param  int  $priority
      * @return void
      */
-    public function listen($events, $listener, $priority = 0)
+    public function listen($events, $listener)
     {
         foreach ((array) $events as $event) {
             if (Str::contains($event, '*')) {
                 $this->setupWildcardListen($event, $listener);
             } else {
-                $this->listeners[$event][$priority][] = $this->makeListener($listener);
-
-                unset($this->sorted[$event]);
+                $this->listeners[$event][] = $this->makeListener($event, $listener);
             }
         }
     }
@@ -96,7 +79,7 @@ public function listen($events, $listener, $priority = 0)
      */
     protected function setupWildcardListen($event, $listener)
     {
-        $this->wildcards[$event][] = $this->makeListener($listener);
+        $this->wildcards[$event][] = $this->makeListener($event, $listener, true);
     }
 
     /**
@@ -152,18 +135,6 @@ protected function resolveSubscriber($subscriber)
         return $subscriber;
     }
 
-    /**
-     * Fire an event until the first non-null response is returned.
-     *
-     * @param  string|object  $event
-     * @param  array  $payload
-     * @return mixed
-     */
-    public function until($event, $payload = [])
-    {
-        return $this->fire($event, $payload, true);
-    }
-
     /**
      * Flush a set of pushed events.
      *
@@ -175,48 +146,26 @@ public function flush($event)
         $this->fire($event.'_pushed');
     }
 
-    /**
-     * Get the event that is currently firing.
-     *
-     * @return string
-     */
-    public function dispatching()
-    {
-        return $this->firing();
-    }
-
-    /**
-     * Get the event that is currently firing.
-     *
-     * @return string
-     */
-    public function firing()
-    {
-        return last($this->firing);
-    }
-
     /**
      * Fire an event and call the listeners.
      *
      * @param  string|object  $event
      * @param  mixed  $payload
-     * @param  bool  $halt
      * @return array|null
      */
-    public function dispatch($event, $payload = [], $halt = false)
+    public function dispatch($event, $payload = [])
     {
-        return $this->fire($event, $payload, $halt);
+        return $this->fire($event, $payload);
     }
 
     /**
      * Fire an event and call the listeners.
      *
      * @param  string|object  $event
      * @param  mixed  $payload
-     * @param  bool  $halt
      * @return array|null
      */
-    public function fire($event, $payload = [], $halt = false)
+    public function fire($event, $payload = [])
     {
         // When the given "event" is actually an object we will assume it is an event
         // object and use the class as the event name and this event itself as the
@@ -225,25 +174,14 @@ public function fire($event, $payload = [], $halt = false)
             $event, $payload
         );
 
-        $responses = [];
-
-        $this->firing[] = $event;
-
         if ($this->shouldBroadcast($payload)) {
             $this->broadcastEvent($payload[0]);
         }
 
-        foreach ($this->getListeners($event) as $listener) {
-            $response = call_user_func_array($listener, $payload);
-
-            // If a response is returned from the listener and event halting is enabled
-            // we will just return this response, and not call the rest of the event
-            // listeners. Otherwise we will add the response on the response list.
-            if (! is_null($response) && $halt) {
-                array_pop($this->firing);
+        $responses = [];
 
-                return $response;
-            }
+        foreach ($this->getListeners($event) as $listener) {
+            $response = $listener($event, $payload);
 
             // If a boolean false is returned from a listener, we will stop propagating
             // the event to any further listeners down in the chain, else we keep on
@@ -255,9 +193,7 @@ public function fire($event, $payload = [], $halt = false)
             $responses[] = $response;
         }
 
-        array_pop($this->firing);
-
-        return $halt ? null : $responses;
+        return $responses;
     }
 
     /**
@@ -306,13 +242,15 @@ protected function broadcastEvent($event)
      */
     public function getListeners($eventName)
     {
-        $wildcards = $this->getWildcardListeners($eventName);
+        $listeners = isset($this->listeners[$eventName]) ? $this->listeners[$eventName] : [];
 
-        if (! isset($this->sorted[$eventName])) {
-            $this->sortListeners($eventName);
-        }
+        $listeners = array_merge(
+            $listeners, $this->getWildcardListeners($eventName)
+        );
 
-        return array_merge($this->sorted[$eventName], $wildcards);
+        return class_exists($eventName, false)
+                    ? $this->addInterfaceListeners($eventName, $listeners)
+                    : $listeners;
     }
 
     /**
@@ -334,33 +272,6 @@ protected function getWildcardListeners($eventName)
         return $wildcards;
     }
 
-    /**
-     * Sort the listeners for a given event by priority.
-     *
-     * @param  string  $eventName
-     * @return void
-     */
-    protected function sortListeners($eventName)
-    {
-        // If listeners exist for the given event, we will sort them by the priority
-        // so that we can call them in the correct order. We will cache off these
-        // sorted event listeners so we do not have to re-sort on every events.
-        $listeners = isset($this->listeners[$eventName])
-                            ? $this->listeners[$eventName] : [];
-
-        if (class_exists($eventName, false)) {
-            $listeners = $this->addInterfaceListeners($eventName, $listeners);
-        }
-
-        if ($listeners) {
-            krsort($listeners);
-
-            $this->sorted[$eventName] = call_user_func_array('array_merge', $listeners);
-        } else {
-            $this->sorted[$eventName] = [];
-        }
-    }
-
     /**
      * Add the listeners for the event's interfaces to the given array.
      *
@@ -372,12 +283,8 @@ protected function addInterfaceListeners($eventName, array $listeners = [])
     {
         foreach (class_implements($eventName) as $interface) {
             if (isset($this->listeners[$interface])) {
-                foreach ($this->listeners[$interface] as $priority => $names) {
-                    if (isset($listeners[$priority])) {
-                        $listeners[$priority] = array_merge($listeners[$priority], $names);
-                    } else {
-                        $listeners[$priority] = $names;
-                    }
+                foreach ($this->listeners[$interface] as $names) {
+                    $listeners = array_merge($listeners, (array) $names);
                 }
             }
         }
@@ -391,9 +298,19 @@ protected function addInterfaceListeners($eventName, array $listeners = [])
      * @param  string|\Closure  $listener
      * @return mixed
      */
-    public function makeListener($listener)
+    public function makeListener($event, $listener, $wildcard = false)
     {
-        return is_string($listener) ? $this->createClassListener($listener) : $listener;
+        if (is_string($listener)) {
+            return $this->createClassListener($listener, $wildcard);
+        }
+
+        return function ($event, $payload) use ($listener, $wildcard) {
+            if ($wildcard) {
+                return $listener($event, $payload);
+            } else {
+                return $listener(...array_values($payload));
+            }
+        };
     }
 
     /**
@@ -402,12 +319,16 @@ public function makeListener($listener)
      * @param  string  $listener
      * @return \Closure
      */
-    public function createClassListener($listener)
+    public function createClassListener($listener, $wildcard = false)
     {
-        return function () use ($listener) {
-            return call_user_func_array(
-                $this->createClassCallable($listener), func_get_args()
-            );
+        return function ($event, $payload) use ($listener, $wildcard) {
+            if ($wildcard) {
+                return call_user_func($this->createClassCallable($listener), $event, $payload);
+            } else {
+                return call_user_func_array(
+                    $this->createClassCallable($listener), $payload
+                );
+            }
         };
     }
 
@@ -533,7 +454,7 @@ public function forget($event)
         if (Str::contains($event, '*')) {
             unset($this->wildcards[$event]);
         } else {
-            unset($this->listeners[$event], $this->sorted[$event]);
+            unset($this->listeners[$event]);
         }
     }
 

src/Illuminate/Support/Testing/Fakes/EventFake.php

@@ -102,10 +102,9 @@ protected function mapEventArguments($arguments)
      *
      * @param  string|array  $events
      * @param  mixed  $listener
-     * @param  int  $priority
      * @return void
      */
-    public function listen($events, $listener, $priority = 0)
+    public function listen($events, $listener)
     {
         //
     }
@@ -144,18 +143,6 @@ public function subscribe($subscriber)
         //
     }
 
-    /**
-     * Fire an event until the first non-null response is returned.
-     *
-     * @param  string  $event
-     * @param  array  $payload
-     * @return mixed
-     */
-    public function until($event, $payload = [])
-    {
-        return $this->dispatch($event, $payload, true);
-    }
-
     /**
      * Flush a set of pushed events.
      *
@@ -172,26 +159,15 @@ public function flush($event)
      *
      * @param  string|object  $event
      * @param  mixed  $payload
-     * @param  bool  $halt
      * @return array|null
      */
-    public function dispatch($event, $payload = [], $halt = false)
+    public function dispatch($event, $payload = [])
     {
         $name = is_object($event) ? get_class($event) : (string) $event;
 
         $this->events[$name][] = func_get_args();
     }
 
-    /**
-     * Get the event that is currently dispatching.
-     *
-     * @return string
-     */
-    public function dispatching()
-    {
-        //
-    }
-
     /**
      * Remove a set of listeners from the dispatcher.
      *