[2.x] fix(Mentions): allow renderer to be used without context (#3954)

* fix(Mentions): allow renderer to be used without context

* test(Mentions): implement test for rendering post without context

* Update UnparsePostMentions.php

* Update PostMentionsTest.php

---------

Co-authored-by: IanM <16573496+imorland@users.noreply.github.com>

extensions/mentions/src/Formatter/FormatPostMentions.php

@@ -12,6 +12,7 @@ namespace Flarum\Mentions\Formatter;
 use Flarum\Discussion\Discussion;
 use Flarum\Http\SlugManager;
 use Flarum\Locale\TranslatorInterface;
+use Flarum\Post\Post;
 use Psr\Http\Message\ServerRequestInterface as Request;
 use s9e\TextFormatter\Renderer;
 use s9e\TextFormatter\Utils;
@@ -24,12 +25,22 @@ class FormatPostMentions
     ) {
     }
 
-    public function __invoke(Renderer $renderer, mixed $context, ?string $xml, Request $request = null): string
+    /**
+     * Configure rendering for post mentions.
+     *
+     * @param \s9e\TextFormatter\Renderer $renderer
+     * @param mixed $context
+     * @param string $xml
+     * @param \Psr\Http\Message\ServerRequestInterface|null $request
+     * @return string $xml to be rendered
+     */
+    public function __invoke(Renderer $renderer, $context, $xml, Request $request = null)
     {
-        $post = $context;
+        return Utils::replaceAttributes($xml, 'POSTMENTION', function ($attributes) use ($context) {
+            $post = (($context && isset($context->getRelations()['mentionsPosts'])) || $context instanceof Post)
+                ? $context->mentionsPosts->find($attributes['id'])
+                : Post::find($attributes['id']);
 
-        return Utils::replaceAttributes($xml, 'POSTMENTION', function ($attributes) use ($post) {
-            $post = $post->mentionsPosts->find($attributes['id']);
             if ($post && $post->user) {
                 $attributes['displayname'] = $post->user->display_name;
             }

extensions/mentions/src/Formatter/UnparsePostMentions.php

@@ -10,6 +10,7 @@
 namespace Flarum\Mentions\Formatter;
 
 use Flarum\Locale\TranslatorInterface;
+use Flarum\Post\Post;
 use s9e\TextFormatter\Utils;
 
 class UnparsePostMentions
@@ -31,10 +32,11 @@ class UnparsePostMentions
      */
     protected function updatePostMentionTags(mixed $context, string $xml): string
     {
-        $post = $context;
+        return Utils::replaceAttributes($xml, 'POSTMENTION', function ($attributes) use ($context) {
+            $post = (($context && isset($context->getRelations()['mentionsPosts'])) || $context instanceof Post)
+                ? $context->mentionsPosts->find($attributes['id'])
+                : Post::find($attributes['id']);
 
-        return Utils::replaceAttributes($xml, 'POSTMENTION', function ($attributes) use ($post) {
-            $post = $post->mentionsPosts->find($attributes['id']);
             if ($post && $post->user) {
                 $attributes['displayname'] = $post->user->display_name;
             }

extensions/mentions/tests/integration/api/PostMentionsTest.php

@@ -11,7 +11,9 @@ namespace Flarum\Mentions\Tests\integration\api;
 
 use Carbon\Carbon;
 use Flarum\Extend;
+use Flarum\Formatter\Formatter;
 use Flarum\Post\CommentPost;
+use Flarum\Post\Post;
 use Flarum\Testing\integration\RetrievesAuthorizedUsers;
 use Flarum\Testing\integration\TestCase;
 use Flarum\User\DisplayName\DriverInterface;
@@ -538,6 +540,40 @@ class PostMentionsTest extends TestCase
         $this->assertStringContainsString('PostMention', $response['data']['attributes']['contentHtml']);
         $this->assertNotNull(CommentPost::find($response['data']['id'])->mentionsPosts->find(11));
     }
+
+    /**
+     * @test
+     */
+    public function rendering_post_mention_with_a_post_context_works()
+    {
+        /** @var Formatter $formatter */
+        $formatter = $this->app()->getContainer()->make(Formatter::class);
+
+        $post = Post::find(4);
+        $user = User::find(1);
+
+        $xml = $formatter->parse($post->content, $post, $user);
+        $renderedHtml = $formatter->render($xml, $post);
+
+        $this->assertStringContainsString('TOBY$', $renderedHtml);
+    }
+
+    /**
+     * @test
+     */
+    public function rendering_post_mention_without_a_context_works()
+    {
+        /** @var Formatter $formatter */
+        $formatter = $this->app()->getContainer()->make(Formatter::class);
+
+        $post = Post::find(4);
+        $user = User::find(1);
+
+        $xml = $formatter->parse($post->content, null, $user);
+        $renderedHtml = $formatter->render($xml);
+
+        $this->assertStringContainsString('TOBY$', $renderedHtml);
+    }
 }
 
 class CustomOtherDisplayNameDriver implements DriverInterface