Add extension for Services::getSharedInstance()

Author: paulbalandan

docs/type-inference.md

@@ -2,6 +2,23 @@
 
 All type inference capabilities of this extension are summarised below:
 
+## Dynamic Function Return Type Extensions
+
+### ServicesFunctionReturnTypeExtension
+
+This extension provides precise return types for the `service()` and `single_service()` functions.
+
+**Before:**
+```php
+\PHPStan\dumpType(service('cache')); // object|null
+
+```
+
+**After:**
+```php
+\PHPStan\dumpType(service('cache')); // CodeIgniter\Cache\CacheInterface
+```
+
 ## Dynamic Static Method Return Type Extensions
 
 ### ReflectionHelperGetPrivateMethodInvokerReturnTypeExtension
@@ -20,9 +37,10 @@ class Foo
         return true;
     }
 }
+
 ```
 
-**Before**
+**Before:**
 ```php
 public function testSomePrivateMethod(): void
 {
@@ -32,7 +50,7 @@ public function testSomePrivateMethod(): void
 
 ```
 
-**After**
+**After:**
 ```php
 public function testSomePrivateMethod(): void
 {
@@ -57,3 +75,43 @@ public function testSomePrivateMethod(): void
 >    class: <Fully qualified class name of class using ReflectionHelper>
 >
 > ```
+
+### ServicesGetSharedInstanceReturnTypeExtension
+
+This extension provides precise return type for the protected static method `getSharedInstance()` of `Services`.
+
+**Before:**
+```php
+<?php
+class MyService extends \Config\Services
+{
+    public static function bar(bool $getShared = true): Bar
+    {
+        if ($getShared) {
+            \PHPStan\dumpType(static::getSharedInstance('bar')); // object
+            return static::getSharedInstance('bar');
+        }
+
+        return new Bar();
+    }
+}
+
+```
+
+**After:**
+```php
+<?php
+class MyService extends \Config\Services
+{
+    public static function bar(bool $getShared = true): Bar
+    {
+        if ($getShared) {
+            \PHPStan\dumpType(static::getSharedInstance('bar')); // Bar
+            return static::getSharedInstance('bar');
+        }
+
+        return new Bar();
+    }
+}
+
+```

extension.neon

@@ -85,6 +85,11 @@ services:
     arguments:
       class: CodeIgniter\Test\CIUnitTestCase
 
+  -
+    class: CodeIgniter\PHPStan\Type\ServicesGetSharedInstanceReturnTypeExtension
+    tags:
+      - phpstan.broker.dynamicStaticMethodReturnTypeExtension
+
   # conditional rules
   -
     class: CodeIgniter\PHPStan\Rules\Functions\FactoriesFunctionArgumentTypeRule

src/Type/ServicesGetSharedInstanceReturnTypeExtension.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) 2023 CodeIgniter Foundation <[email protected]>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\PHPStan\Type;
+
+use CodeIgniter\Config\BaseService;
+use PhpParser\Node\Expr\StaticCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\MethodReflection;
+use PHPStan\Type\DynamicStaticMethodReturnTypeExtension;
+use PHPStan\Type\Type;
+
+class ServicesGetSharedInstanceReturnTypeExtension implements DynamicStaticMethodReturnTypeExtension
+{
+    public function __construct(
+        private readonly ServicesReturnTypeHelper $servicesReturnTypeHelper,
+    ) {}
+
+    public function getClass(): string
+    {
+        return BaseService::class;
+    }
+
+    public function isStaticMethodSupported(MethodReflection $methodReflection): bool
+    {
+        return $methodReflection->getName() === 'getSharedInstance';
+    }
+
+    public function getTypeFromStaticMethodCall(MethodReflection $methodReflection, StaticCall $methodCall, Scope $scope): ?Type
+    {
+        $arguments = $methodCall->getArgs();
+
+        if ($arguments === []) {
+            return null;
+        }
+
+        return $this->servicesReturnTypeHelper->check($scope->getType($arguments[0]->value), $scope);
+    }
+}

tests/Type/DynamicStaticMethodReturnTypeExtensionTest.php

@@ -38,5 +38,7 @@ public function testFileAsserts(string $assertType, string $file, mixed ...$args
     public static function provideFileAssertsCases(): iterable
     {
         yield from self::gatherAssertTypes(__DIR__ . '/data/reflection-helper.php');
+
+        yield from self::gatherAssertTypes(__DIR__ . '/data/services-get-shared-instance.php');
     }
 }

tests/Type/data/services-get-shared-instance.php

@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) 2023 CodeIgniter Foundation <[email protected]>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\PHPStan\Tests\Fixtures\Type;
+
+use CodeIgniter\Cache\CacheInterface;
+use CodeIgniter\CLI\Commands;
+use CodeIgniter\Config\Services;
+use CodeIgniter\Debug\Exceptions;
+use CodeIgniter\Debug\Iterator;
+use CodeIgniter\Debug\Toolbar;
+use CodeIgniter\Email\Email;
+use CodeIgniter\Filters\Filters;
+use CodeIgniter\HTTP\CLIRequest;
+use CodeIgniter\HTTP\ResponseInterface;
+use CodeIgniter\Log\Logger;
+use CodeIgniter\Pager\Pager;
+use CodeIgniter\Validation\ValidationInterface;
+use CodeIgniter\View\Cell;
+use CodeIgniter\View\Parser;
+use CodeIgniter\View\View;
+
+use function PHPStan\Testing\assertType;
+
+final class SharedServices extends Services
+{
+    public static function forTesting(): void
+    {
+        assertType(CacheInterface::class, self::getSharedInstance('cache'));
+        assertType(Commands::class, self::getSharedInstance('commands'));
+        assertType(CLIRequest::class, self::getSharedInstance('clirequest'));
+        assertType(Email::class, self::getSharedInstance('email'));
+        assertType(Exceptions::class, self::getSharedInstance('exceptions'));
+        assertType(Filters::class, self::getSharedInstance('filters'));
+        assertType(Iterator::class, self::getSharedInstance('iterator'));
+        assertType(Logger::class, self::getSharedInstance('logger'));
+        assertType(Pager::class, self::getSharedInstance('pager'));
+        assertType(Parser::class, self::getSharedInstance('parser'));
+        assertType(View::class, self::getSharedInstance('renderer'));
+        assertType('CodeIgniter\HTTP\CLIRequest|CodeIgniter\HTTP\IncomingRequest', self::getSharedInstance('request'));
+        assertType(ResponseInterface::class, self::getSharedInstance('response'));
+        assertType(Toolbar::class, self::getSharedInstance('toolbar'));
+        assertType(ValidationInterface::class, self::getSharedInstance('validation'));
+        assertType(Cell::class, self::getSharedInstance('viewcell'));
+        assertType('null', self::getSharedInstance('createRequest'));
+    }
+}