[FEATURE] Respect ContainerInterface in StandardVariableProvider (#1002)

With this change, it is possible to access properties of objects implementing
`Psr\Container\ContainerInterface` from Fluid templates using the normal
object accessor syntax. The interface requires two methods `has()` and `get()`
which are used by Fluid to obtain the requested property from the object.

composer.json

@@ -22,7 +22,8 @@
         "phpstan/phpstan": "^1.11.5",
         "phpstan/phpstan-phpunit": "^1.4.0",
         "phpunit/phpunit": "^11.2.5",
-        "t3docs/fluid-documentation-generator": "^4.3"
+        "t3docs/fluid-documentation-generator": "^4.3",
+        "psr/container": "^2.0"
     },
     "suggest": {
         "ext-json": "PHP JSON is needed when using JSONVariableProvider: A relatively rare use case",

src/Core/Variables/StandardVariableProvider.php

@@ -9,6 +9,8 @@
 
 namespace TYPO3Fluid\Fluid\Core\Variables;
 
+use Psr\Container\ContainerInterface;
+
 /**
  * Class StandardVariableProvider
  */
@@ -117,6 +119,10 @@ public function getByPath(string $path): mixed
                 continue;
             }
             if (is_object($subject)) {
+                if ($subject instanceof ContainerInterface && $subject->has($pathSegment)) {
+                    $subject = $subject->get($pathSegment);
+                    continue;
+                }
                 $upperCasePropertyName = ucfirst($pathSegment);
                 $getMethod = 'get' . $upperCasePropertyName;
                 if (method_exists($subject, $getMethod)) {

tests/Unit/Core/Variables/Fixtures/StandardVariableProviderContainerFixture.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file belongs to the package "TYPO3 Fluid".
+ * See LICENSE.txt that was shipped with this package.
+ */
+
+namespace TYPO3Fluid\Fluid\Tests\Unit\Core\Variables\Fixtures;
+
+use Psr\Container\ContainerInterface;
+
+/**
+ * Used by StandardVariableProviderTest
+ */
+final readonly class StandardVariableProviderContainerFixture implements ContainerInterface
+{
+    public function __construct(private array $properties) {}
+
+    public function get(string $id): mixed
+    {
+        return $this->properties[$id] ?? null;
+    }
+
+    public function has(string $id): bool
+    {
+        return array_key_exists($id, $this->properties);
+    }
+}

tests/Unit/Core/Variables/StandardVariableProviderTest.php

@@ -14,6 +14,7 @@
 use PHPUnit\Framework\TestCase;
 use TYPO3Fluid\Fluid\Core\Variables\InvalidVariableIdentifierException;
 use TYPO3Fluid\Fluid\Core\Variables\StandardVariableProvider;
+use TYPO3Fluid\Fluid\Tests\Unit\Core\Variables\Fixtures\StandardVariableProviderContainerFixture;
 use TYPO3Fluid\Fluid\Tests\Unit\Core\Variables\Fixtures\StandardVariableProviderModelFixture;
 
 final class StandardVariableProviderTest extends TestCase
@@ -245,6 +246,69 @@ public static function getPathTestValues(): array
                 'user.invalid',
                 null,
             ],
+            'access container' => [
+                [
+                    'user' => new StandardVariableProviderContainerFixture(['name' => 'Foobar Name']),
+                ],
+                'user.name',
+                'Foobar Name',
+            ],
+            'access container getter that returns empty string' => [
+                [
+                    'user' => new StandardVariableProviderContainerFixture(['name' => '']),
+                ],
+                'user.name',
+                '',
+            ],
+            'access container getter that returns FALSE' => [
+                [
+                    'user' => new StandardVariableProviderContainerFixture(['name' => false]),
+                ],
+                'user.name',
+                false,
+            ],
+            'access container getter that returns object' => [
+                [
+                    'user' => new StandardVariableProviderContainerFixture(['object' => new \stdClass()]),
+                ],
+                'user.object',
+                new \stdClass(),
+            ],
+            'access container getter that returns object recursive' => [
+                [
+                    'user' => new StandardVariableProviderContainerFixture(['object' => new StandardVariableProviderModelFixture('Foobar Name')]),
+                ],
+                'user.object.name',
+                'Foobar Name',
+            ],
+            'access container getter that returns container recursive' => [
+                [
+                    'user' => new StandardVariableProviderContainerFixture(['object' => new StandardVariableProviderContainerFixture(['name' => 'Foobar Name'])]),
+                ],
+                'user.object.name',
+                'Foobar Name',
+            ],
+            'access container getter that returns array' => [
+                [
+                    'user' => new StandardVariableProviderContainerFixture(['array' => ['foo' => 'bar']]),
+                ],
+                'user.array',
+                ['foo' => 'bar'],
+            ],
+            'access container getter that returns value of array' => [
+                [
+                    'user' => new StandardVariableProviderContainerFixture(['array' => ['foo' => 'bar']]),
+                ],
+                'user.array.foo',
+                'bar',
+            ],
+            'access container not existing returns null' => [
+                [
+                    'user' => new StandardVariableProviderContainerFixture(['name' => 'Foobar Name']),
+                ],
+                'user.invalid',
+                null,
+            ],
             'access dynamic variable using invalid variable reference' => [
                 [],
                 '{invalid}',