[12.x] Add Singleton and Scoped attributes to Container (#56334)

* Add Singleton and Scoped attributes

* Add to instances on subsequent calls so reflection isn't necessary after

* Don't add it to the instances

Author: riasvdv

src/Illuminate/Container/Attributes/Scoped.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Illuminate\Container\Attributes;
+
+use Attribute;
+
+#[Attribute(Attribute::TARGET_CLASS)]
+final class Scoped
+{
+}

src/Illuminate/Container/Attributes/Singleton.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Illuminate\Container\Attributes;
+
+use Attribute;
+
+#[Attribute(Attribute::TARGET_CLASS)]
+final class Singleton
+{
+}

src/Illuminate/Container/Container.php

@@ -5,6 +5,8 @@
 use ArrayAccess;
 use Closure;
 use Exception;
+use Illuminate\Container\Attributes\Scoped;
+use Illuminate\Container\Attributes\Singleton;
 use Illuminate\Contracts\Container\BindingResolutionException;
 use Illuminate\Contracts\Container\CircularDependencyException;
 use Illuminate\Contracts\Container\Container as ContainerContract;
@@ -252,9 +254,33 @@ public function resolved($abstract)
      */
     public function isShared($abstract)
     {
-        return isset($this->instances[$abstract]) ||
-               (isset($this->bindings[$abstract]['shared']) &&
-               $this->bindings[$abstract]['shared'] === true);
+        if (isset($this->instances[$abstract])) {
+            return true;
+        }
+
+        if (isset($this->bindings[$abstract]['shared']) && $this->bindings[$abstract]['shared'] === true) {
+            return true;
+        }
+
+        if (! class_exists($abstract)) {
+            return false;
+        }
+
+        $reflection = new ReflectionClass($abstract);
+
+        if (! empty($reflection->getAttributes(Singleton::class))) {
+            return true;
+        }
+
+        if (! empty($reflection->getAttributes(Scoped::class))) {
+            if (! in_array($abstract, $this->scopedInstances, true)) {
+                $this->scopedInstances[] = $abstract;
+            }
+
+            return true;
+        }
+
+        return false;
     }
 
     /**

tests/Container/ContainerTest.php

@@ -3,6 +3,8 @@
 namespace Illuminate\Tests\Container;
 
 use Attribute;
+use Illuminate\Container\Attributes\Scoped;
+use Illuminate\Container\Attributes\Singleton;
 use Illuminate\Container\Container;
 use Illuminate\Container\EntryNotFoundException;
 use Illuminate\Contracts\Container\BindingResolutionException;
@@ -740,6 +742,30 @@ public function testMethodLevelContextualBinding()
         $this->assertInstanceOf(ContainerImplementationStub::class, $result);
     }
 
+    public function testContainerSingletonAttribute()
+    {
+        $container = new Container;
+        $firstInstantiation = $container->get(ContainerSingletonAttribute::class);
+
+        $secondInstantiation = $container->get(ContainerSingletonAttribute::class);
+
+        $this->assertSame($firstInstantiation, $secondInstantiation);
+    }
+
+    public function testContainerScopedAttribute()
+    {
+        $container = new Container;
+        $firstInstantiation = $container->get(ContainerScopedAttribute::class);
+        $secondInstantiation = $container->get(ContainerScopedAttribute::class);
+
+        $this->assertSame($firstInstantiation, $secondInstantiation);
+
+        $container->forgetScopedInstances();
+
+        $thirdInstantiation = $container->get(ContainerScopedAttribute::class);
+        $this->assertNotSame($firstInstantiation, $thirdInstantiation);
+    }
+
     // public function testContainerCanCatchCircularDependency()
     // {
     //     $this->expectException(\Illuminate\Contracts\Container\CircularDependencyException::class);
@@ -899,3 +925,13 @@ public function __construct(
         $this->currentlyResolving = $currentlyResolving;
     }
 }
+
+#[Singleton]
+class ContainerSingletonAttribute
+{
+}
+
+#[Scoped]
+class ContainerScopedAttribute
+{
+}