[1.x] Conditional extender instantiation

framework/core/src/Extend/Conditional.php

@@ -13,28 +13,49 @@
 use Flarum\Extension\ExtensionManager;
 use Illuminate\Contracts\Container\Container;
 
+/**
+ * The Conditional extender allows developers to conditionally apply other extenders
+ * based on either boolean values or results from callable functions.
+ *
+ * This is useful for applying extenders only if certain conditions are met,
+ * such as the presence of an enabled extension or a specific configuration setting.
+ */
 class Conditional implements ExtenderInterface
 {
     /**
-     * @var array<array{condition: bool|callable, extenders: ExtenderInterface[]}>
+     * An array of conditions and their associated extenders.
+     *
+     * Each entry should have:
+     * - 'condition': a boolean or callable that should return a boolean.
+     * - 'extenders': an array of extenders, a callable returning an array of extenders, or an invokable class string.
+     *
+     * @var array<array{condition: bool|callable, extenders: ExtenderInterface[]|callable|string}>
      */
     protected $conditions = [];
 
     /**
-     * @param ExtenderInterface[] $extenders
+     * Apply extenders only if a specific extension is enabled.
+     *
+     * @param string $extensionId The ID of the extension.
+     * @param ExtenderInterface[]|callable|string $extenders An array of extenders, a callable returning an array of extenders, or an invokable class string.
+     * @return self
      */
-    public function whenExtensionEnabled(string $extensionId, array $extenders): self
+    public function whenExtensionEnabled(string $extensionId, $extenders): self
     {
         return $this->when(function (ExtensionManager $extensions) use ($extensionId) {
             return $extensions->isEnabled($extensionId);
         }, $extenders);
     }
 
     /**
-     * @param bool|callable $condition
-     * @param ExtenderInterface[] $extenders
+     * Apply extenders based on a condition.
+     *
+     * @param bool|callable $condition A boolean or callable that should return a boolean.
+     *                                 If this evaluates to true, the extenders will be applied.
+     * @param ExtenderInterface[]|callable|string $extenders An array of extenders, a callable returning an array of extenders, or an invokable class string.
+     * @return self
      */
-    public function when($condition, array $extenders): self
+    public function when($condition, $extenders): self
     {
         $this->conditions[] = [
             'condition' => $condition,
@@ -44,6 +65,13 @@ public function when($condition, array $extenders): self
         return $this;
     }
 
+    /**
+     * Iterates over the conditions and applies the associated extenders if the conditions are met.
+     *
+     * @param Container $container
+     * @param Extension|null $extension
+     * @return void
+     */
     public function extend(Container $container, Extension $extension = null)
     {
         foreach ($this->conditions as $condition) {
@@ -52,7 +80,13 @@ public function extend(Container $container, Extension $extension = null)
             }
 
             if ($condition['condition']) {
-                foreach ($condition['extenders'] as $extender) {
+                $extenders = $condition['extenders'];
+
+                if (is_string($extenders) || is_callable($extenders)) {
+                    $extenders = $container->call($extenders);
+                }
+
+                foreach ($extenders as $extender) {
                     $extender->extend($container, $extension);
                 }
             }

framework/core/tests/integration/extenders/ConditionalTest.php

@@ -159,4 +159,140 @@ public function conditional_injects_dependencies_to_condition_callable()
 
         $this->app();
     }
+
+    /** @test */
+    public function conditional_does_not_instantiate_extender_if_condition_is_false_using_callable()
+    {
+        $this->extend(
+            (new Extend\Conditional())
+                ->when(false, TestExtender::class)
+        );
+
+        $this->app();
+
+        $response = $this->send(
+            $this->request('GET', '/api', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $payload = json_decode($response->getBody()->getContents(), true);
+
+        $this->assertArrayNotHasKey('customConditionalAttribute', $payload['data']['attributes']);
+    }
+
+    /** @test */
+    public function conditional_does_instantiate_extender_if_condition_is_true_using_callable()
+    {
+        $this->extend(
+            (new Extend\Conditional())
+                ->when(true, TestExtender::class)
+        );
+
+        $this->app();
+
+        $response = $this->send(
+            $this->request('GET', '/api', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $payload = json_decode($response->getBody()->getContents(), true);
+
+        $this->assertArrayHasKey('customConditionalAttribute', $payload['data']['attributes']);
+    }
+
+    /** @test */
+    public function conditional_does_not_instantiate_extender_if_condition_is_false_using_callback()
+    {
+        $this->extend(
+            (new Extend\Conditional())
+                ->when(false, function (): array {
+                    return [
+                        (new Extend\ApiSerializer(ForumSerializer::class))
+                            ->attributes(function () {
+                                return [
+                                    'customConditionalAttribute' => true
+                                ];
+                            })
+                    ];
+                })
+        );
+
+        $this->app();
+
+        $response = $this->send(
+            $this->request('GET', '/api', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $payload = json_decode($response->getBody()->getContents(), true);
+
+        $this->assertArrayNotHasKey('customConditionalAttribute', $payload['data']['attributes']);
+    }
+
+    /** @test */
+    public function conditional_does_instantiate_extender_if_condition_is_true_using_callback()
+    {
+        $this->extend(
+            (new Extend\Conditional())
+                ->when(true, function (): array {
+                    return [
+                        (new Extend\ApiSerializer(ForumSerializer::class))
+                            ->attributes(function () {
+                                return [
+                                    'customConditionalAttribute' => true
+                                ];
+                            })
+                    ];
+                })
+        );
+
+        $this->app();
+
+        $response = $this->send(
+            $this->request('GET', '/api', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $payload = json_decode($response->getBody()->getContents(), true);
+
+        $this->assertArrayHasKey('customConditionalAttribute', $payload['data']['attributes']);
+    }
+
+    /** @test */
+    public function conditional_does_not_work_if_extension_is_disabled()
+    {
+        $this->extend(
+            (new Extend\Conditional())
+                ->whenExtensionEnabled('dummy-extension-id', TestExtender::class)
+        );
+
+        $response = $this->send(
+            $this->request('GET', '/api', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $payload = json_decode($response->getBody()->getContents(), true);
+
+        $this->assertArrayNotHasKey('customConditionalAttribute', $payload['data']['attributes']);
+    }
+}
+
+class TestExtender
+{
+    public function __invoke(): array
+    {
+        return [
+            (new Extend\ApiSerializer(ForumSerializer::class))
+                ->attributes(function () {
+                    return [
+                        'customConditionalAttribute' => true
+                    ];
+                })
+        ];
+    }
 }