Create attributes AsTwigFilter, AsTwigFunction and AsTwigTest to ease extension development

doc/advanced.rst

@@ -756,6 +756,145 @@ The ``getTests()`` method lets you add new test functions::
         // ...
     }
 
+Using PHP Attributes to define extensions
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. versionadded:: 3.9
+
+    The attribute classes were added in Twig 3.9.
+
+From PHP 8.0, you can use the attributes ``#[AsTwigFilter]``, ``#[AsTwigFunction]``,
+and ``#[AsTwigTest]`` on any method of any class to define filters, functions, and tests.
+
+Create a class with the attribute ``#[AsTwigExtension]``::
+
+    use Twig\Attribute\AsTwigExtension;
+    use Twig\Attribute\AsTwigFilter;
+    use Twig\Attribute\AsTwigFunction;
+    use Twig\Attribute\AsTwigTest;
+
+    #[AsTwigExtension]
+    class ProjectExtension
+    {
+        #[AsTwigFilter('rot13')]
+        public static function rot13(string $string): string
+        {
+            // ...
+        }
+
+        #[AsTwigFunction('lipsum')]
+        public static function lipsum(int $count): string
+        {
+            // ...
+        }
+
+        #[AsTwigTest('even')]
+        public static function isEven(int $number): bool
+        {
+            // ...
+        }
+    }
+
+Then register the extension class::
+
+    $twig = new \Twig\Environment($loader);
+    $twig->addExtension(ProjectExtension::class);
+
+If all the methods are static, you are done. The ``Project_Twig_Extension`` class will
+never be instantiated and the class attributes will be scanned only when a template
+is compiled.
+
+Otherwise, if some methods are not static, you need to register the class as
+a runtime extension using one of the runtime loaders::
+
+    use Twig\Attribute\AsTwigExtension;
+    use Twig\Attribute\AsTwigFunction;
+
+    #[AsTwigExtension]
+    class ProjectExtension
+    {
+        // Inject hypothetical dependencies
+        public function __construct(private LipsumProvider $lipsumProvider) {}
+
+        #[AsTwigFunction('lipsum')]
+        public function lipsum(int $count): string
+        {
+            return $this->lipsumProvider->lipsum($count);
+        }
+    }
+
+    $twig = new \Twig\Environment($loader);
+    $twig->addExtension(ProjectExtension::class);
+    $twig->addRuntimeLoader(new \Twig\RuntimeLoader\FactoryLoader([
+        ProjectExtension::class => function () use ($lipsumProvider) {
+            return new ProjectExtension($lipsumProvider);
+        },
+    ]));
+
+Or use the instance directly if you don't need lazy-loading::
+
+    $twig = new \Twig\Environment($loader);
+    $twig->addExtension(new ProjectExtension($lipsumProvider));
+
+``#[AsTwigFilter]`` and ``#[AsTwigFunction]`` support ``isSafe``, ``preEscape``, and
+``isVariadic`` options::
+
+    use Twig\Attribute\AsTwigExtension;
+    use Twig\Attribute\AsTwigFilter;
+    use Twig\Attribute\AsTwigFunction;
+
+    #[AsTwigExtension]
+    class ProjectExtension
+    {
+        #[AsTwigFilter('rot13', isSafe: ['html'])]
+        public static function rot13(string $string): string
+        {
+            // ...
+        }
+
+        #[AsTwigFunction('lipsum', isSafe: ['html'], preEscape: 'html')]
+        public static function lipsum(int $count): string
+        {
+            // ...
+        }
+    }
+
+If you want to access the current environment instance in your filter or function,
+add the ``Twig\Environment`` type to the first argument of the method::
+
+    class ProjectExtension
+    {
+        #[AsTwigFunction('lipsum')]
+        public function lipsum(\Twig\Environment $env, int $count): string
+        {
+            // ...
+        }
+    }
+
+If you want to access the current context in your filter or function, add an argument
+with type and name ``array $context`` first or after ``\Twig\Environment``::
+
+    class ProjectExtension
+    {
+        #[AsTwigFunction('lipsum')]
+        public function lipsum(array $context, int $count): string
+        {
+            // ...
+        }
+    }
+
+``#[AsTwigFilter]`` and ``#[AsTwigFunction]`` support variadic arguments
+automatically when applied to variadic methods::
+
+    class ProjectExtension
+    {
+        #[AsTwigFilter('thumbnail')]
+        public function thumbnail(string $file, mixed ...$options): string
+        {
+            // ...
+        }
+    }
+
 Definition vs Runtime
 ~~~~~~~~~~~~~~~~~~~~~
 

src/Attribute/AsTwigExtension.php

@@ -0,0 +1,20 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Attribute;
+
+/**
+ * Identifies a class that uses PHP attributes to define filters, functions, or tests.
+ */
+#[\Attribute(\Attribute::TARGET_CLASS)]
+final class AsTwigExtension
+{
+}

src/Attribute/AsTwigFilter.php

@@ -0,0 +1,78 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Attribute;
+
+use Twig\Node\Node;
+use Twig\TwigFilter;
+
+/**
+ * Registers a method as template filter.
+ *
+ * If the first argument of the method has Twig\Environment type-hint, the filter will receive the current environment.
+ * If the next argument of the method is named $context and has array type-hint, the filter will receive the current context.
+ * Additional arguments of the method come from the filter call.
+ *
+ *     #[AsTwigFilter('foo')]
+ *     function fooFilter(Environment $env, array $context, $string, $arg1 = null, ...) { ... }
+ *
+ * @see TwigFilter
+ */
+#[\Attribute(\Attribute::TARGET_METHOD | \Attribute::IS_REPEATABLE)]
+final class AsTwigFilter
+{
+    public function __construct(
+        /**
+         * The name of the filter in Twig.
+         *
+         * @var non-empty-string $name
+         */
+        public string $name,
+
+        /**
+         * List of formats in which you want the raw output to be printed unescaped.
+         *
+         * @var list<string>|null $isSafe
+         */
+        public ?array $isSafe = null,
+
+        /**
+         * Function called at compilation time to determine if the filter is safe.
+         *
+         * @var callable(Node):bool $isSafeCallback
+         */
+        public ?string $isSafeCallback = null,
+
+        /**
+         * Some filters may need to work on input that is already escaped or safe, for
+         * example when adding (safe) HTML tags to originally unsafe output. In such a
+         * case, set preEscape to an escape format to escape the input data before it
+         * is run through the filter.
+         */
+        public ?string $preEscape = null,
+
+        /**
+         * Preserves the safety of the value that the filter is applied to.
+         */
+        public ?array $preservesSafety = null,
+
+        /**
+         * Set to true if the filter is deprecated.
+         */
+        public bool|string $deprecated = false,
+
+        /**
+         * The alternative filter name to suggest when the deprecated filter is called.
+         */
+        public ?string $alternative = null,
+    ) {
+    }
+}

src/Attribute/AsTwigFunction.php

@@ -0,0 +1,65 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Attribute;
+
+use Twig\Node\Node;
+use Twig\TwigFunction;
+
+/**
+ * Registers a method as template function.
+ *
+ * If the first argument of the method has Twig\Environment type-hint, the function will receive the current environment.
+ * If the next argument of the method is named $context and has array type-hint, the function will receive the current context.
+ * Additional arguments of the method come from the function call.
+ *
+ *     #[AsTwigFunction('foo')]
+ *     function fooFunction(Environment $env, array $context, $string, $arg1 = null, ...) { ... }
+ *
+ * @see TwigFunction
+ */
+#[\Attribute(\Attribute::TARGET_METHOD | \Attribute::IS_REPEATABLE)]
+final class AsTwigFunction
+{
+    public function __construct(
+        /**
+         * The name of the function in Twig.
+         *
+         * @var non-empty-string $name
+         */
+        public string $name,
+
+        /**
+         * List of formats in which you want the raw output to be printed unescaped.
+         *
+         * @var list<string>|null $isSafe
+         */
+        public ?array $isSafe = null,
+
+        /**
+         * Function called at compilation time to determine if the function is safe.
+         *
+         * @var callable(Node):bool $isSafeCallback
+         */
+        public ?string $isSafeCallback = null,
+
+        /**
+         * Set to true if the function is deprecated.
+         */
+        public bool|string $deprecated = false,
+
+        /**
+         * The alternative function name to suggest when the deprecated function is called.
+         */
+        public ?string $alternative = null,
+    ) {
+    }
+}

src/Attribute/AsTwigTest.php

@@ -0,0 +1,50 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Attribute;
+
+use Twig\TwigTest;
+
+/**
+ * Registers a method as template test.
+ *
+ * If the first argument of the method has Twig\Environment type-hint, the test will receive the current environment.
+ * If the next argument of the method is named $context and has array type-hint, the test will receive the current context.
+ * The last argument of the method is the value to be tested, if any.
+ *
+ *     #[AsTwigTest('foo')]
+ *     public function fooTest(Environment $env, array $context, $value, $arg1 = null) { ... }
+ *
+ * @see TwigTest
+ */
+#[\Attribute(\Attribute::TARGET_METHOD | \Attribute::IS_REPEATABLE)]
+final class AsTwigTest
+{
+    public function __construct(
+        /**
+         * The name of the filter in Twig.
+         *
+         * @var non-empty-string $name
+         */
+        public string $name,
+
+        /**
+         * Set to true if the function is deprecated.
+         */
+        public bool|string $deprecated = false,
+
+        /**
+         * The alternative function name to suggest when the deprecated function is called.
+         */
+        public ?string $alternative = null,
+    ) {
+    }
+}

src/Environment.php

@@ -616,14 +616,17 @@ public function getRuntime(string $class)
         throw new RuntimeError(sprintf('Unable to load the "%s" runtime.', $class));
     }
 
-    public function addExtension(ExtensionInterface $extension)
+    /**
+     * @param ExtensionInterface|object|class-string $extension
+     */
+    public function addExtension(object|string $extension)
     {
         $this->extensionSet->addExtension($extension);
         $this->updateOptionsHash();
     }
 
     /**
-     * @param ExtensionInterface[] $extensions An array of extensions
+     * @param list<ExtensionInterface|object|class-string> $extensions An array of extensions
      */
     public function setExtensions(array $extensions)
     {