Added CacheInterface.stubphp from symfony contracts (#74)

Author: vudaltsov

composer.json

@@ -18,6 +18,7 @@
     "require-dev": {
         "doctrine/orm": "^2.7",
         "phpunit/phpunit": "~7.5",
+        "symfony/cache-contracts": "^1.0 || ^2.0",
         "symfony/console": "*",
         "symfony/messenger": "^4.2 || ^5.0",
         "symfony/security-guard": "^4.0 || ^5.0",

src/Stubs/common/CacheInterface.stubphp

@@ -0,0 +1,16 @@
+<?php
+
+namespace Symfony\Contracts\Cache;
+
+use Psr\Cache\CacheItemInterface;
+
+interface CacheInterface
+{
+    /**
+     * @template T
+     *
+     * @psalm-param CallbackInterface|callable(CacheItemInterface, bool): T $callback
+     * @psalm-return T
+     */
+    public function get(string $key, callable $callback, float $beta = null, array &$metadata = null);
+}

tests/acceptance/acceptance/CacheInterface.feature

@@ -0,0 +1,37 @@
+@symfony-common
+Feature: CacheInterface
+
+  Background:
+    Given I have the following config
+      """
+      <?xml version="1.0"?>
+      <psalm errorLevel="1">
+        <projectFiles>
+          <directory name="."/>
+          <ignoreFiles> <directory name="../../vendor"/> </ignoreFiles>
+        </projectFiles>
+
+        <plugins>
+          <pluginClass class="Psalm\SymfonyPsalmPlugin\Plugin"/>
+        </plugins>
+      </psalm>
+      """
+
+  Scenario: CacheInterface::get has the same return type as the passed callback
+    Given I have the following code
+      """
+      <?php
+
+      use Psr\Cache\CacheItemInterface;
+      use Symfony\Contracts\Cache\CacheInterface;
+
+      function test(CacheInterface $cache): stdClass
+      {
+        return $cache->get('key', function (CacheItemInterface $item, bool &$save): stdClass {
+          return new stdClass();
+        });
+      }
+
+      """
+    When I run Psalm
+    Then I see no errors