[7.x] Fix output of component attributes (#31994)

* Fix output of component attributes

* Add missing merge() to test

Author: perifer

src/Illuminate/View/ComponentAttributeBag.php

@@ -113,12 +113,6 @@ public function merge(array $attributeDefaults = [])
         }, $attributeDefaults);
 
         foreach ($this->attributes as $key => $value) {
-            if ($value === true) {
-                $attributes[$key] = $key;
-
-                continue;
-            }
-
             if ($key !== 'class') {
                 $attributes[$key] = $value;
 
@@ -130,7 +124,7 @@ public function merge(array $attributeDefaults = [])
             ));
         }
 
-        return new static(array_merge($attributeDefaults, array_filter($attributes)));
+        return new static(array_merge($attributeDefaults, $attributes));
     }
 
     /**
@@ -230,9 +224,15 @@ public function __toString()
         $string = '';
 
         foreach ($this->attributes as $key => $value) {
-            $string .= $value === true
-                    ? ' '.$key
-                    : ' '.$key.'="'.str_replace('"', '\\"', trim($value)).'"';
+            if ($value === false || is_null($value)) {
+                continue;
+            }
+
+            if ($value === true) {
+                $value = $key;
+            }
+
+            $string .= ' '.$key.'="'.str_replace('"', '\\"', trim($value)).'"';
         }
 
         return trim($string);

tests/View/ViewComponentAttributeBagTest.php

@@ -27,5 +27,18 @@ public function testAttributeRetrieval()
         $bag = new ComponentAttributeBag([]);
 
         $this->assertSame('class="mt-4"', (string) $bag->merge(['class' => 'mt-4']));
+
+        $bag = new ComponentAttributeBag([
+            'test-string' => 'ok',
+            'test-null' => null,
+            'test-false' => false,
+            'test-true' => true,
+            'test-0' => 0,
+            'test-0-string' => '0',
+            'test-empty-string' => '',
+        ]);
+
+        $this->assertSame('test-string="ok" test-true="test-true" test-0="0" test-0-string="0" test-empty-string=""', (string) $bag);
+        $this->assertSame('test-string="ok" test-true="test-true" test-0="0" test-0-string="0" test-empty-string=""', (string) $bag->merge());
     }
 }