Support multiple error reporters

The error handling middleware now expects an array of reporters.
Extensions can register new reporters in the container like this:

    use Flarum\Foundation\ErrorHandling\Reporter;

    $container->tag(NewReporter::class, Reporter::class);

Note that this is just an implementation detail and will be hidden
behind an extender.

src/Admin/AdminServiceProvider.php

@@ -58,7 +58,7 @@ class AdminServiceProvider extends AbstractServiceProvider
             $pipe->pipe(new HttpMiddleware\HandleErrors(
                 $app->make(Registry::class),
                 $app->inDebugMode() ? $app->make(WhoopsRenderer::class) : $app->make(ViewRenderer::class),
-                $app->make(Reporter::class)
+                $app->tagged(Reporter::class)
             ));
 
             $pipe->pipe($app->make(HttpMiddleware\ParseJsonBody::class));

src/Api/ApiServiceProvider.php

@@ -53,7 +53,7 @@ class ApiServiceProvider extends AbstractServiceProvider
             $pipe->pipe(new HttpMiddleware\HandleErrors(
                 $app->make(Registry::class),
                 $app->make(JsonApiRenderer::class),
-                $app->make(Reporter::class)
+                $app->tagged(Reporter::class)
             ));
 
             $pipe->pipe($app->make(HttpMiddleware\ParseJsonBody::class));

src/Forum/ForumServiceProvider.php

@@ -68,7 +68,7 @@ class ForumServiceProvider extends AbstractServiceProvider
             $pipe->pipe(new HttpMiddleware\HandleErrors(
                 $app->make(Registry::class),
                 $app->inDebugMode() ? $app->make(WhoopsRenderer::class) : $app->make(ViewRenderer::class),
-                $app->make(Reporter::class)
+                $app->tagged(Reporter::class)
             ));
 
             $pipe->pipe($app->make(HttpMiddleware\ParseJsonBody::class));

src/Foundation/ErrorServiceProvider.php

@@ -71,6 +71,6 @@ class ErrorServiceProvider extends AbstractServiceProvider
             );
         });
 
-        $this->app->singleton(Reporter::class, LogReporter::class);
+        $this->app->tag(LogReporter::class, Reporter::class);
     }
 }

src/Http/Middleware/HandleErrors.php

@@ -13,7 +13,6 @@ namespace Flarum\Http\Middleware;
 
 use Flarum\Foundation\ErrorHandling\Formatter;
 use Flarum\Foundation\ErrorHandling\Registry;
-use Flarum\Foundation\ErrorHandling\Reporter;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 use Psr\Http\Server\MiddlewareInterface as Middleware;
@@ -33,15 +32,15 @@ class HandleErrors implements Middleware
     protected $formatter;
 
     /**
-     * @var Reporter
+     * @var \Flarum\Foundation\ErrorHandling\Reporter[]
      */
-    protected $reporter;
+    protected $reporters;
 
-    public function __construct(Registry $registry, Formatter $formatter, Reporter $reporter)
+    public function __construct(Registry $registry, Formatter $formatter, array $reporters)
     {
         $this->registry = $registry;
         $this->formatter = $formatter;
-        $this->reporter = $reporter;
+        $this->reporters = $reporters;
     }
 
     /**
@@ -55,7 +54,9 @@ class HandleErrors implements Middleware
             $error = $this->registry->handle($e);
 
             if ($error->shouldBeReported()) {
-                $this->reporter->report($error);
+                foreach ($this->reporters as $reporter) {
+                    $reporter->report($error);
+                }
             }
 
             return $this->formatter->format($error, $request);

src/Install/Installer.php

@@ -43,7 +43,7 @@ class Installer implements AppInterface
         $pipe->pipe(new HandleErrors(
             $this->container->make(Registry::class),
             $this->container->make(WhoopsRenderer::class),
-            $this->container->make(Reporter::class)
+            $this->container->tagged(Reporter::class)
         ));
         $pipe->pipe($this->container->make(StartSession::class));
         $pipe->pipe(