[11.x] Handle HtmlString constructed with a null (#53367)

Author: sperelson

src/Illuminate/Support/HtmlString.php

@@ -42,7 +42,7 @@ public function toHtml()
      */
     public function isEmpty()
     {
-        return $this->html === '';
+        return ($this->html ?? '') === '';
     }
 
     /**
@@ -62,6 +62,6 @@ public function isNotEmpty()
      */
     public function __toString()
     {
-        return $this->toHtml();
+        return $this->toHtml() ?? '';
     }
 }

tests/Support/SupportHtmlStringTest.php

@@ -39,13 +39,20 @@ public function testToString()
         $str = '<h1>foo</h1>';
         $html = new HtmlString('<h1>foo</h1>');
         $this->assertEquals($str, (string) $html);
+
+        // Check if HtmlString gracefully handles a null value
+        $html = new HtmlString(null);
+        $this->assertIsString((string) $html);
     }
 
     public function testIsEmpty(): void
     {
         // Check if HtmlString correctly identifies an empty string as empty
         $this->assertTrue((new HtmlString(''))->isEmpty());
 
+        // Check if HtmlString identifies a null value as empty
+        $this->assertTrue((new HtmlString(null))->isEmpty());
+
         // HtmlString with whitespace should not be considered as empty
         $this->assertFalse((new HtmlString('   '))->isEmpty());