Add ManifestDoesNotExistException and Solution (#4455)

Co-authored-by: Matthew Penner <matthew@pterodactyl.io>

app/Exceptions/ManifestDoesNotExistException.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace Pterodactyl\Exceptions;
+
+use Exception;
+use Spatie\Ignition\Contracts\Solution;
+use Spatie\Ignition\Contracts\ProvidesSolution;
+
+class ManifestDoesNotExistException extends Exception implements ProvidesSolution
+{
+    public function getSolution(): Solution
+    {
+        return new Solutions\ManifestDoesNotExistSolution();
+    }
+}

app/Exceptions/Solutions/ManifestDoesNotExistSolution.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Pterodactyl\Exceptions\Solutions;
+
+use Spatie\Ignition\Contracts\Solution;
+
+class ManifestDoesNotExistSolution implements Solution
+{
+    public function getSolutionTitle(): string
+    {
+        return "The manifest.json file hasn't been generated yet";
+    }
+
+    public function getSolutionDescription(): string
+    {
+        return 'Run yarn run build:production to build the frontend first.';
+    }
+
+    public function getDocumentationLinks(): array
+    {
+        return [
+            'Docs' => 'https://github.com/pterodactyl/panel/blob/develop/package.json',
+        ];
+    }
+}

app/Services/Helpers/AssetHashService.php

@@ -5,6 +5,7 @@ namespace Pterodactyl\Services\Helpers;
 use Illuminate\Support\Arr;
 use Illuminate\Filesystem\FilesystemManager;
 use Illuminate\Contracts\Filesystem\Filesystem;
+use Pterodactyl\Exceptions\ManifestDoesNotExistException;
 
 class AssetHashService
 {
@@ -106,6 +107,11 @@ class AssetHashService
             );
         }
 
-        return static::$manifest;
+        $manifest = static::$manifest;
+        if ($manifest === null) {
+            throw new ManifestDoesNotExistException();
+        }
+
+        return $manifest;
     }
 }