Extension to detect return type of MailerAwareTrait::getMailer

extension.neon

@@ -62,3 +62,7 @@ services:
 		class: CakeDC\PHPStan\PhpDoc\TableAssociationTypeNodeResolverExtension
 		tags:
 			- phpstan.phpDoc.typeNodeResolverExtension
+	-
+		class: CakeDC\PHPStan\Type\GetMailerExpressionTypeResolverExtension
+		tags:
+			- phpstan.broker.expressionTypeResolverExtension

src/Type/GetMailerExpressionTypeResolverExtension.php

@@ -0,0 +1,102 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Copyright 2020, Cake Development Corporation (https://www.cakedc.com)
+ *
+ * Licensed under The MIT License
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright Copyright 2020, Cake Development Corporation (https://www.cakedc.com)
+ * @license   MIT License (http://www.opensource.org/licenses/mit-license.php)
+ */
+
+namespace CakeDC\PHPStan\Type;
+
+use Cake\Mailer\MailerAwareTrait;
+use CakeDC\PHPStan\Utility\CakeNameRegistry;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Identifier;
+use PhpParser\Node\Scalar\String_;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\ClassReflection;
+use PHPStan\Type\ExpressionTypeResolverExtension;
+use PHPStan\Type\ObjectType;
+use PHPStan\Type\ThisType;
+use PHPStan\Type\Type;
+
+class GetMailerExpressionTypeResolverExtension implements ExpressionTypeResolverExtension
+{
+    /**
+     * @var string
+     */
+    protected string $methodName;
+    protected string $namespaceFormat;
+    protected string $targetTrait;
+
+    /**
+     * Contructor
+     */
+    public function __construct()
+    {
+        $this->targetTrait = MailerAwareTrait::class;
+        $this->methodName = 'getMailer';
+        $this->namespaceFormat = '%s\\Mailer\\%sMailer';
+    }
+
+    /**
+     * @param \PhpParser\Node\Expr $expr
+     * @param \PHPStan\Analyser\Scope $scope
+     * @return \PHPStan\Type\Type|null
+     */
+    public function getType(Expr $expr, Scope $scope): ?Type
+    {
+        if (
+            !$expr instanceof Expr\MethodCall
+            || !$expr->name instanceof Identifier
+            || $expr->name->toString() !== $this->methodName
+        ) {
+            return null;
+        }
+
+        $callerType = $scope->getType($expr->var);
+
+        if (
+            !$callerType instanceof ThisType
+            || !$this->isFromTargetTrait($callerType->getClassReflection())
+        ) {
+            return null;
+        }
+
+        $value = $expr->getArgs()[0]->value ?? null;
+        if (!$value instanceof String_) {
+            return null;
+        }
+        $className = CakeNameRegistry::getClassName($value->value, $this->namespaceFormat);
+        if ($className !== null) {
+            return new ObjectType($className);
+        }
+
+        return null;
+    }
+
+    /**
+     * @param \PHPStan\Reflection\ClassReflection $reflection
+     * @return bool
+     */
+    protected function isFromTargetTrait(ClassReflection $reflection): bool
+    {
+        foreach ($reflection->getTraits() as $trait) {
+            if ($trait->getName() === $this->targetTrait) {
+                return true;
+            }
+        }
+        foreach ($reflection->getParents() as $parent) {
+            if ($this->isFromTargetTrait($parent)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}

tests/test_app/Command/MyTestExtendedCommand.php

@@ -0,0 +1,30 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Copyright 2020, Cake Development Corporation (https://www.cakedc.com)
+ *
+ * Licensed under The MIT License
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright Copyright 2020, Cake Development Corporation (https://www.cakedc.com)
+ * @license   MIT License (http://www.opensource.org/licenses/mit-license.php)
+ */
+
+namespace App\Command;
+
+use Cake\Console\Arguments;
+use Cake\Console\ConsoleIo;
+
+class MyTestExtendedCommand extends MyTestLoadCommand
+{
+    /**
+     * @inheritDoc
+     */
+    public function execute(Arguments $args, ConsoleIo $io)
+    {
+        $this->fetchTable('VeryCustomize00009Articles')->newSample();
+        $io->helper('MyHeading')->headingOne('Sample Text 02');
+        $this->getMailer('MyTestLoad')->testing();
+    }
+}

tests/test_app/Command/MyTestLoadCommand.php

@@ -16,9 +16,12 @@
 use Cake\Command\Command;
 use Cake\Console\Arguments;
 use Cake\Console\ConsoleIo;
+use Cake\Mailer\MailerAwareTrait;
 
 class MyTestLoadCommand extends Command
 {
+    use MailerAwareTrait;
+
     /**
      * @inheritDoc
      */
@@ -29,5 +32,6 @@ public function execute(Arguments $args, ConsoleIo $io)
         $io->helper('progress')->increment(1);
         $io->out($io->helper('BazBaz')->foo());
         $io->helper('MyHeading')->headingOne('Sample Text 01');
+        $this->getMailer('MyTestLoad')->testing();
     }
 }

tests/test_app/Mailer/MyTestLoadMailer.php

@@ -28,4 +28,11 @@ protected function sampleLoading()
             ->newSample();
         $this->viewBuilder()->setVar('article', $article);
     }
+
+    /**
+     * @return void
+     */
+    public function testing()
+    {
+    }
 }