Initialises Psalm

Closes #8

Signed-off-by: George Steel <[email protected]>

.gitattributes

@@ -6,3 +6,6 @@
 /phpcs.xml export-ignore
 /phpunit.xml.dist export-ignore
 /test/ export-ignore
+/psalm.xml export-ignore
+/psalm-baseline.xml export-ignore
+/.psr-container.php.stub export-ignore

.psr-container.php.stub

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psr\Container {
+    /**
+     * Provides automatic type inference for Psalm when retrieving a service from a container using a FQCN
+     */
+    interface ContainerInterface
+    {
+        /**
+         * @param string|class-string $id
+         * @return bool
+         */
+        public function has(string $id);
+
+        /**
+         * @template T
+         * @psalm-param string|class-string<T> $id
+         * @psalm-return ($id is class-string ? T : mixed)
+         */
+        public function get(string $id);
+    }
+}

composer.json

@@ -46,7 +46,9 @@
         "laminas/laminas-uri": "^2.9.1",
         "laminas/laminas-view": "^2.14.2",
         "phpspec/prophecy-phpunit": "^2.0.1",
-        "phpunit/phpunit": "^9.5.10"
+        "phpunit/phpunit": "^9.5.10",
+        "psalm/plugin-phpunit": "^0.17.0",
+        "vimeo/psalm": "^4.24"
     },
     "suggest": {
         "laminas/laminas-config": "^3.7, to provide page configuration (optional, as arrays and Traversables are also allowed)",
@@ -73,7 +75,8 @@
         "cs-check": "phpcs",
         "cs-fix": "phpcbf",
         "test": "phpunit --colors=always",
-        "test-coverage": "phpunit --colors=always --coverage-clover clover.xml"
+        "test-coverage": "phpunit --colors=always --coverage-clover clover.xml",
+        "static-analysis": "psalm --shepherd --stats"
     },
     "conflict": {
         "zendframework/zend-navigation": "*"