feature #3169 [TwigComponent] Allow using directory name as component name for anonymous components (andyexeter)

This PR was merged into the 2.x branch.

Discussion
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[TwigComponent] Allow using directory name as component name for anonymous components

| Q              | A
| -------------- | ---
| Bug fix?       | no
| New feature?   | yes <!-- please update src/**/CHANGELOG.md files -->
| Deprecations?  | no <!-- if yes, also update UPGRADE-*.md and src/**/CHANGELOG.md -->
| Documentation? | yes <!-- required for new features, or documentation updates -->
| Issues         | Fix #1998  <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License        | MIT

This pull request introduces support for using `index.html.twig` as a component template when the component is placed in a directory named after itself. This helps avoid repetition and improves organization for nested components. The documentation is updated to explain this feature, and corresponding logic and tests are added to ensure correct template resolution.

Commits
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7b0f600 Allow using directory name as component name for anonymous components

Author: Kocal

src/TwigComponent/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 -  Add option `profiler.collect_components` to control component data collection
    in the profiler (enabled in debug mode by default)
+-  Add support for using directory name as component name for anonymous components
 
 ## 2.30
 

src/TwigComponent/doc/index.rst

@@ -676,6 +676,43 @@ the subdirectory:
     {# renders as: #}
     <button class="primary">Click Me!</button>
 
+If your anonymous component lives in a directory with the same name, you can
+name the component file ``index.html.twig`` to avoid repetition:
+
+.. code-block:: html+twig
+
+    {# templates/components/Menu/index.html.twig #}
+    <nav {{ attributes.defaults({class: 'menu'}) }}>
+        <ul>
+            {% block content %}{% endblock %}
+        </ul>
+    </nav>
+
+.. code-block:: html+twig
+
+    {# templates/components/Menu/Item.html.twig #}
+    {% props href, label %}
+    <li {{ attributes.defaults({class: 'menu__item'}) }}>
+        <a href="{{ href }}">{% block content %}{{ label }}{% endblock %}</a>
+    </li>
+
+.. code-block:: html+twig
+
+    {# index.html.twig #}
+    ...
+    <twig:Menu>
+        <twig:Menu:Item href="/">Home</twig:Menu:Item>
+        <twig:Menu:Item href="/about">About</twig:Menu:Item>
+    </twig:Menu>
+
+    {# renders as: #}
+    <nav class="menu">
+        <ul>
+            <li class="menu__item"><a href="/">Home</a></li>
+            <li class="menu__item"><a href="/about">About</a></li>
+        </ul>
+    </nav>
+
 Like normal, you can pass extra attributes that will be rendered on the element:
 
 .. code-block:: html+twig

src/TwigComponent/src/ComponentTemplateFinder.php

@@ -66,6 +66,11 @@ public function findAnonymousComponentTemplate(string $name): ?string
             return $template;
         }
 
+        $template = rtrim($this->directory, '/').'/'.$componentPath.'/index.html.twig';
+        if ($loader->exists($template)) {
+            return $template;
+        }
+
         $parts = explode('/', $componentPath, 2);
         if (\count($parts) < 2) {
             return null;

src/TwigComponent/tests/Fixtures/templates/anonymous/Bar.html.twig

@@ -178,6 +178,29 @@ public function testLoadingAnonymousComponentFromBundle()
         $this->assertNull($metadata->get('class'));
     }
 
+    public function testLoadingAnonymousComponentWithFallback()
+    {
+        self::bootKernel(['environment' => 'anonymous_directory']);
+
+        $metadata = $this->factory()->metadataFor('Menu');
+
+        $this->assertSame('anonymous/Menu/index.html.twig', $metadata->getTemplate());
+        $this->assertSame('Menu', $metadata->getName());
+        $this->assertNull($metadata->get('class'));
+
+        $metadata = $this->factory()->metadataFor('Menu:Item');
+
+        $this->assertSame('anonymous/Menu/Item.html.twig', $metadata->getTemplate());
+        $this->assertSame('Menu:Item', $metadata->getName());
+        $this->assertNull($metadata->get('class'));
+
+        // Ensure anonymous/Bar.html.twig takes precedence over anonymous/Bar/index.html.twig
+        $metadata = $this->factory()->metadataFor('Bar');
+        $this->assertSame('anonymous/Bar.html.twig', $metadata->getTemplate());
+        $this->assertSame('Bar', $metadata->getName());
+        $this->assertNull($metadata->get('class'));
+    }
+
     public function testAutoNamingInSubDirectory()
     {
         $metadata = $this->factory()->metadataFor('SubDirectory:ComponentInSubDirectory');

src/TwigComponent/tests/Fixtures/templates/anonymous/Bar/index.html.twig

@@ -117,13 +117,18 @@ public function testFindTemplateWithinDirectory()
             'foo/bar.html.twig',
             'bar/foo/bar.html.twig',
             'foo/foo/bar.html.twig',
+            'foo/qux/index.html.twig',
+            'foo/foo/baz/index.html.twig',
         ];
         $loader = $this->createLoader($templates);
         $finder = new ComponentTemplateFinder($loader, 'foo');
 
         $this->assertEquals('foo/bar.html.twig', $finder->findAnonymousComponentTemplate('bar'));
         $this->assertEquals('foo/foo/bar.html.twig', $finder->findAnonymousComponentTemplate('foo:bar'));
         $this->assertEquals('foo/foo/bar.html.twig', $finder->findAnonymousComponentTemplate('foo:bar'));
+
+        $this->assertEquals('foo/qux/index.html.twig', $finder->findAnonymousComponentTemplate('qux'));
+        $this->assertEquals('foo/foo/baz/index.html.twig', $finder->findAnonymousComponentTemplate('foo:baz'));
     }
 
     private function createLoader(array $templates): LoaderInterface