Get rid of event subscribers that resolve services too early, part 1

Refs flarum/core#1578.

extend.php

@@ -9,6 +9,8 @@
  * file that was distributed with this source code.
  */
 
+use Flarum\Api\Event\Serializing;
+use Flarum\Discussion\Event\Saving;
 use Flarum\Extend;
 use Flarum\Tags\Access;
 use Flarum\Tags\Api\Controller;
@@ -35,11 +37,14 @@
 
     function (Dispatcher $events) {
         $events->subscribe(Listener\AddDiscussionTagsRelationship::class);
+
         $events->subscribe(Listener\AddForumTagsRelationship::class);
+        $events->listen(Serializing::class, Listener\PrepareForumTagsApiAttributes::class);
+
         $events->subscribe(Listener\CreatePostWhenTagsAreChanged::class);
         $events->subscribe(Listener\FilterDiscussionListByTags::class);
         $events->subscribe(Listener\FilterPostsQueryByTag::class);
-        $events->subscribe(Listener\SaveTagsToDatabase::class);
+        $events->listen(Saving::class, Listener\SaveTagsToDatabase::class);
         $events->subscribe(Listener\UpdateTagMetadata::class);
 
         $events->subscribe(Access\GlobalPolicy::class);

src/Listener/AddForumTagsRelationship.php

@@ -12,30 +12,15 @@
 namespace Flarum\Tags\Listener;
 
 use Flarum\Api\Controller\ShowForumController;
-use Flarum\Api\Event\Serializing;
 use Flarum\Api\Event\WillGetData;
 use Flarum\Api\Event\WillSerializeData;
 use Flarum\Api\Serializer\ForumSerializer;
 use Flarum\Event\GetApiRelationship;
-use Flarum\Settings\SettingsRepositoryInterface;
 use Flarum\Tags\Tag;
 use Illuminate\Contracts\Events\Dispatcher;
 
 class AddForumTagsRelationship
 {
-    /**
-     * @var SettingsRepositoryInterface
-     */
-    protected $settings;
-
-    /**
-     * @param SettingsRepositoryInterface $settings
-     */
-    public function __construct(SettingsRepositoryInterface $settings)
-    {
-        $this->settings = $settings;
-    }
-
     /**
      * @param Dispatcher $events
      */
@@ -44,7 +29,6 @@ public function subscribe(Dispatcher $events)
         $events->listen(GetApiRelationship::class, [$this, 'getApiRelationship']);
         $events->listen(WillSerializeData::class, [$this, 'loadTagsRelationship']);
         $events->listen(WillGetData::class, [$this, 'includeTagsRelationship']);
-        $events->listen(Serializing::class, [$this, 'prepareApiAttributes']);
     }
 
     /**
@@ -84,17 +68,4 @@ public function includeTagsRelationship(WillGetData $event)
             $event->addInclude(['tags', 'tags.lastPostedDiscussion', 'tags.parent']);
         }
     }
-
-    /**
-     * @param Serializing $event
-     */
-    public function prepareApiAttributes(Serializing $event)
-    {
-        if ($event->isSerializer(ForumSerializer::class)) {
-            $event->attributes['minPrimaryTags'] = $this->settings->get('flarum-tags.min_primary_tags');
-            $event->attributes['maxPrimaryTags'] = $this->settings->get('flarum-tags.max_primary_tags');
-            $event->attributes['minSecondaryTags'] = $this->settings->get('flarum-tags.min_secondary_tags');
-            $event->attributes['maxSecondaryTags'] = $this->settings->get('flarum-tags.max_secondary_tags');
-        }
-    }
 }

src/Listener/PrepareForumTagsApiAttributes.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Tags\Listener;
+
+use Flarum\Api\Event\Serializing;
+use Flarum\Api\Serializer\ForumSerializer;
+use Flarum\Settings\SettingsRepositoryInterface;
+
+class PrepareForumTagsApiAttributes
+{
+    /**
+     * @var SettingsRepositoryInterface
+     */
+    protected $settings;
+
+    /**
+     * @param SettingsRepositoryInterface $settings
+     */
+    public function __construct(SettingsRepositoryInterface $settings)
+    {
+        $this->settings = $settings;
+    }
+
+    public function handle(Serializing $event)
+    {
+        if ($event->isSerializer(ForumSerializer::class)) {
+            $event->attributes['minPrimaryTags'] = $this->settings->get('flarum-tags.min_primary_tags');
+            $event->attributes['maxPrimaryTags'] = $this->settings->get('flarum-tags.max_primary_tags');
+            $event->attributes['minSecondaryTags'] = $this->settings->get('flarum-tags.min_secondary_tags');
+            $event->attributes['maxSecondaryTags'] = $this->settings->get('flarum-tags.max_secondary_tags');
+        }
+    }
+}

src/Listener/SaveTagsToDatabase.php

@@ -17,7 +17,6 @@
 use Flarum\Tags\Event\DiscussionWasTagged;
 use Flarum\Tags\Tag;
 use Flarum\User\Exception\PermissionDeniedException;
-use Illuminate\Contracts\Events\Dispatcher;
 use Illuminate\Contracts\Validation\Factory;
 use Symfony\Component\Translation\TranslatorInterface;
 
@@ -50,20 +49,12 @@ public function __construct(SettingsRepositoryInterface $settings, Factory $vali
         $this->translator = $translator;
     }
 
-    /**
-     * @param Dispatcher $events
-     */
-    public function subscribe(Dispatcher $events)
-    {
-        $events->listen(Saving::class, [$this, 'whenDiscussionIsSaving']);
-    }
-
     /**
      * @param Saving $event
      * @throws PermissionDeniedException
      * @throws ValidationException
      */
-    public function whenDiscussionIsSaving(Saving $event)
+    public function handle(Saving $event)
     {
         $discussion = $event->discussion;
         $actor = $event->actor;