Add MagicRelationsTrait::relationNames() method

src/Trait/MagicRelationsTrait.php

@@ -10,15 +10,19 @@
 use Yiisoft\ActiveRecord\ActiveRecordInterface;
 use Yiisoft\Db\Exception\InvalidArgumentException;
 
+use function get_class_methods;
 use function is_a;
 use function lcfirst;
 use function method_exists;
+use function str_ends_with;
+use function str_starts_with;
 use function substr;
 use function ucfirst;
 
 /**
  * Trait to define {@see ActiveRecordInterface::relationQuery()} method to access relation queries of an ActiveRecord
- * instance.
+ * instance. Also, it defines {@see ActiveRecordInterface::relationNames()} method to get names of all relations
+ * defined in the ActiveRecord class.
  */
 trait MagicRelationsTrait
 {
@@ -75,4 +79,37 @@ public function relationQuery(string $name): ActiveQueryInterface
 
         return $this->$getter();
     }
+
+    /**
+     * Returns names of all relations defined in the ActiveRecord class using getter methods with `get` prefix and
+     * `Query` suffix.
+     *
+     * @return string[]
+     *
+     * @throws ReflectionException
+     */
+    public function relationNames(): array
+    {
+        $methods = get_class_methods($this);
+
+        $relations = [];
+
+        foreach ($methods as $method) {
+            if (str_starts_with($method, 'get') && str_ends_with($method, 'Query')) {
+                $reflection = new ReflectionMethod($this, $method);
+                $type = $reflection->getReturnType();
+
+                if (
+                    $type === null
+                    || !is_a('\\' . $type->getName(), ActiveQueryInterface::class, true)
+                ) {
+                    continue;
+                }
+
+                $relations[] = lcfirst(substr($method, 3, -5));
+            }
+        }
+
+        return $relations;
+    }
 }

tests/MagicActiveRecordTest.php

@@ -7,8 +7,10 @@
 use DivisionByZeroError;
 use ReflectionException;
 use Yiisoft\ActiveRecord\ActiveQuery;
+use Yiisoft\ActiveRecord\Tests\Stubs\MagicActiveRecord\Alpha;
 use Yiisoft\ActiveRecord\Tests\Stubs\MagicActiveRecord\Animal;
 use Yiisoft\ActiveRecord\Tests\Stubs\MagicActiveRecord\Cat;
+use Yiisoft\ActiveRecord\Tests\Stubs\MagicActiveRecord\Category;
 use Yiisoft\ActiveRecord\Tests\Stubs\MagicActiveRecord\Customer;
 use Yiisoft\ActiveRecord\Tests\Stubs\MagicActiveRecord\CustomerClosureField;
 use Yiisoft\ActiveRecord\Tests\Stubs\MagicActiveRecord\CustomerForArrayable;
@@ -948,4 +950,34 @@ public function testGetDirtyAttributesWithProperties(): void
             $customer->getDirtyAttributes(['id', 'email', 'address', 'unknown']),
         );
     }
+
+    public function testRelationNames(): void
+    {
+        $this->checkFixture($this->db(), 'animal');
+
+        $animal = new Animal();
+
+        $this->assertEmpty($animal->relationNames());
+
+        $alpha = new Alpha();
+
+        $this->assertSame(['betas'], $alpha->relationNames());
+
+        $customer = new Customer();
+
+        $this->assertSame([
+            'profile',
+            'ordersPlain',
+            'orders',
+            'ordersNoOrder',
+            'expensiveOrders',
+            'ordersWithItems',
+            'expensiveOrdersWithNullFK',
+            'ordersWithNullFK',
+            'orders2',
+            'orderItems',
+            'orderItems2',
+            'items2',
+        ], $customer->relationNames());
+    }
 }