[9.x] Check for \Stringable interface before casting using (string) (#41671)

* Check for `\Stringable` interface before casting using `(string)`

Signed-off-by: Mior Muhammad Zaki <[email protected]>

* wip

Author: crynobone

src/Illuminate/Collections/Collection.php

@@ -490,7 +490,7 @@ public function groupBy($groupBy, $preserveKeys = false)
             foreach ($groupKeys as $groupKey) {
                 $groupKey = match (true) {
                     is_bool($groupKey) => (int) $groupKey,
-                    is_object($groupKey) => (string) $groupKey,
+                    $groupKey instanceof \Stringable => (string) $groupKey,
                     default => $groupKey,
                 };
 

tests/Support/SupportCollectionTest.php

@@ -3023,6 +3023,30 @@ public function testGroupByAttribute($collection)
         $this->assertEquals([1 => [['rating' => 1, 'url' => '1'], ['rating' => 1, 'url' => '1']], 2 => [['rating' => 2, 'url' => '2']]], $result->toArray());
     }
 
+    /**
+     * @dataProvider collectionClassProvider
+     */
+    public function testGroupByAttributeWithStringableKey($collection)
+    {
+        $data = new $collection($payload = [
+            ['name' => Str::of('Laravel'), 'url' => '1'],
+            ['name' => new HtmlString('Laravel'), 'url' => '1'],
+            ['name' => new class()
+            {
+                public function __toString()
+                {
+                    return 'Framework';
+                }
+            }, 'url' => '2', ],
+        ]);
+
+        $result = $data->groupBy('name');
+        $this->assertEquals(['Laravel' => [$payload[0], $payload[1]], 'Framework' => [$payload[2]]], $result->toArray());
+
+        $result = $data->groupBy('url');
+        $this->assertEquals(['1' => [$payload[0], $payload[1]], '2' => [$payload[2]]], $result->toArray());
+    }
+
     /**
      * @dataProvider collectionClassProvider
      */