fix(view): comment out empty slots (#938)

brendt · web-flow · commit 1b3433d83952 · 2025-03-01T20:44:30.000+01:00
diff --git a/src/Tempest/Debug/src/DOMDebug.php b/src/Tempest/Debug/src/DOMDebug.php
@@ -0,0 +1,48 @@
+<?php
+
+namespace Tempest\Debug;
+
+use Dom\Comment;
+use Dom\Document;
+use Dom\DocumentType;
+use Dom\Element as DomElement;
+use Dom\Node;
+use Dom\NodeList;
+use Dom\Text;
+
+final readonly class DOMDebug
+{
+    public static function dump(Document|NodeList $dom): void
+    {
+        if ($dom instanceof Document) {
+            $dom = $dom->childNodes;
+        }
+
+        $content = [];
+
+        foreach ($dom as $node) {
+            $content[] = self::dumpNode($node);
+        }
+
+        lw(implode(PHP_EOL, $content));
+    }
+
+    private static function dumpNode(Node $node, int $depth = 0): string
+    {
+        $content = str_repeat(' ', $depth * 4);
+
+        $content .= match (true) {
+            $node instanceof DocumentType => 'doctype',
+            $node instanceof Text => trim($node->textContent) !== '' ? 'text' : '',
+            $node instanceof Comment => '// comment',
+            $node instanceof DomElement => "<{$node->tagName}>",
+            default => 'unknown',
+        };
+
+        foreach ($node->childNodes as $child) {
+            $content .= PHP_EOL . self::dumpNode($child, $depth + 1);
+        }
+
+        return $content;
+    }
+}
diff --git a/src/Tempest/View/src/Elements/ViewComponentElement.php b/src/Tempest/View/src/Elements/ViewComponentElement.php
@@ -104,7 +104,9 @@ public function compile(): string
                     $slot = $this->getSlot($name);
 
                     if ($slot === null) {
-                        return $matches[0];
+                        // A slot doesn't have any content, so we'll comment it out.
+                        // This is to prevent DOM parsing errors (slots in <head> tags is one example, see #937)
+                        return '<!--' . $matches[0] . '-->';
                     }
 
                     return $slot->compile();
diff --git a/tests/Integration/View/ViewComponentTest.php b/tests/Integration/View/ViewComponentTest.php
@@ -482,4 +482,25 @@ public function test_full_html_document_as_component(): void
             </body></html>
         HTML, $html);
     }
+    
+    public function test_empty_slots_are_commented_out(): void
+    {
+        $this->registerViewComponent('x-layout', <<<'HTML'
+        <html lang="en">
+        <head>
+            <x-slot name="styles" />
+            <link rel="stylesheet" href="#" />
+        </head>
+        </html>
+        HTML);
+
+        $html = $this->render(<<<'HTML'
+        <x-layout>
+        </x-layout>
+        HTML);
+
+        $this->assertStringEqualsStringIgnoringLineEndings(<<<'HTML'
+        <html lang="en"><head><!--<x-slot name="styles" ></x-slot>--><link rel="stylesheet" href="#"></link></head><body></body></html>
+        HTML, $html);
+    }
 }

Original file line number	Diff line number	Diff line change
`@@ -104,7 +104,9 @@ public function compile(): string`
`104`	`104`	`$slot = $this->getSlot($name);`
`105`	`105`
`106`	`106`	`if ($slot === null) {`
`107`		`- return $matches[0];`
	`107`	`+ // A slot doesn't have any content, so we'll comment it out.`
	`108`	`+ // This is to prevent DOM parsing errors (slots in <head> tags is one example, see #937)`
	`109`	`+ return '<!--' . $matches[0] . '-->';`
`108`	`110`	`}`
`109`	`111`
`110`	`112`	`return $slot->compile();`