Installed Psalm, set up static analysis

Fixed a couple of minor issues

.github/workflows/php.yml

@@ -34,5 +34,8 @@ jobs:
     - name: Install dependencies
       run: composer install --prefer-dist --no-progress
 
-    - name: Run test suite
+    - name: Run Test Suite
       run: XDEBUG_MODE=coverage ./vendor/bin/phpunit tests --coverage-filter src --coverage-text
+    
+    - name: Run Static Analysis
+      run: ./vendor/bin/psalm

composer.json

@@ -34,6 +34,7 @@
     },
     "require-dev": {
         "guzzlehttp/guzzle": "^7.3",
-        "phpunit/phpunit": "^9.5"
+        "phpunit/phpunit": "^9.5",
+        "vimeo/psalm": "^4.7"
     }
 }

psalm.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0"?>
+<psalm
+    errorLevel="4"
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="src" />
+        <ignoreFiles>
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+</psalm>

src/Server.php

@@ -369,7 +369,7 @@ class Server {
 					}
 
 					// Check that this token either grants at most the profile scope.
-					$requestedScopes = explode(' ', $authCode['scope'] ?? '');
+					$requestedScopes = array_filter(explode(' ', $authCode['scope'] ?? ''));
 					if (!empty($requestedScopes) && $requestedScopes != ['profile']) {
 						$this->logger->error("An exchange request for a token granting scopes other than “profile” was sent to the authorization endpoint.");
 						throw IndieAuthException::create(IndieAuthException::INVALID_GRANT, $request);

src/Storage/FilesystemJsonStorage.php

@@ -40,7 +40,7 @@ class FilesystemJsonStorage implements TokenStorageInterface, LoggerAwareInterfa
 	public function __construct(string $path, string $secret, ?int $authCodeTtl=null, ?int $accessTokenTtl=null, $cleanUpNow=false, ?LoggerInterface $logger=null) {
 		$this->logger = $logger ?? new NullLogger();
 
-		if (!is_string($secret) || strlen($secret) < 64) {
+		if (strlen($secret) < 64) {
 			throw new Exception("\$secret must be a string with a minimum length of 64 characters. Make one with Taproot\IndieAuth\generateRandomString(64)");
 		}
 		$this->secret = $secret;