Add psalm

.github/workflows/shepherd.yml

@@ -0,0 +1,22 @@
+name: Shepherd
+
+on:
+  pull_request:
+  push:
+    branches:
+      - "master"
+  schedule:
+    - cron: "0 17 * * *"
+
+jobs:
+  build:
+    runs-on: ubuntu-18.04
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-progress --no-suggest
+
+      - name: Run Psalm
+        run: vendor/bin/psalm --show-info=false --stats --output-format=github --shepherd --threads=$(nproc)

composer.json

@@ -25,8 +25,10 @@
         "phpstan/phpstan-phpunit": "0.12.10",
         "phpstan/phpstan-strict-rules": "0.12.4",
         "phpunit/phpunit": "^9.0",
+        "psalm/plugin-phpunit": "^0.12.2",
         "simpod/php-coveralls-mirror": "^3.0",
-        "thecodingmachine/phpstan-safe-rule": "^1.0"
+        "thecodingmachine/phpstan-safe-rule": "^1.0",
+        "vimeo/psalm": "^3.16"
     },
     "autoload": {
         "psr-4": {

psalm.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0"?>
+<psalm
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    totallyTyped="true"
+    resolveFromConfigFile="true"
+    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>
+    <plugins>
+        <pluginClass class="Psalm\PhpUnitPlugin\Plugin" />
+    </plugins>
+</psalm>

src/Builder/FieldBuilder.php

@@ -9,8 +9,8 @@
 
 class FieldBuilder
 {
-    /** @var mixed[] */
-    private $parameters;
+    /** @var array<string, mixed|array<string|mixed>> */
+    private $parameters = [];
 
     final private function __construct(string $name, Type $type)
     {
@@ -51,6 +51,8 @@ public function addArgument(string $name, Type $type, ?string $description = nul
     }
 
     /**
+     * @see ResolveInfo
+     *
      * @param callable(mixed, array<mixed>, mixed, ResolveInfo) : mixed $resolver
      *
      * @return static

src/Builder/ObjectBuilder.php

@@ -15,8 +15,8 @@ class ObjectBuilder extends TypeBuilder
     /** @var callable|mixed[][] */
     private $fields = [];
 
-    /** @var callable(mixed, array<mixed>, mixed, ResolveInfo) : mixed */
-    private $fieldResolver;
+    /** @var callable(mixed, array<mixed>, mixed, ResolveInfo) : mixed|null */
+    private $fieldResolver = null;
 
     /**
      * @return static

src/Builder/TypeBuilder.php

@@ -15,8 +15,8 @@ abstract class TypeBuilder
     /** @var string */
     private $name;
 
-    /** @var string */
-    private $description;
+    /** @var string|null */
+    private $description = null;
 
     final protected function __construct(string $name)
     {

src/Builder/UnionBuilder.php

@@ -12,8 +12,8 @@ class UnionBuilder extends TypeBuilder
     /** @var callable(object, mixed, ResolveInfo)|null */
     private $resolveType;
 
-    /** @var ObjectType[] */
-    private $types;
+    /** @var ObjectType[]|null */
+    private $types = null;
 
     /**
      * @return static

src/Error/FormattedError.php

@@ -14,6 +14,7 @@ class FormattedError extends \GraphQL\Error\FormattedError
      */
     public static function createFromException(Throwable $exception, int $debug = DebugFlag::NONE, $internalErrorMessage = null): array
     {
+        /** @var array<string, array<string, mixed>> $arrayError */
         $arrayError = parent::createFromException($exception, $debug, $internalErrorMessage);
 
         if ($exception instanceof \GraphQL\Error\Error && $exception->getPrevious() instanceof Error) {

src/Type/DateTimeType.php

@@ -11,9 +11,11 @@
 use GraphQL\Language\AST\StringValueNode;
 use GraphQL\Type\Definition\CustomScalarType;
 use GraphQL\Utils\Utils;
+use InvalidArgumentException;
 use SimPod\GraphQLUtils\Exception\InvalidArgument;
 
 use function assert;
+use function is_string;
 use function Safe\preg_match;
 use function Safe\substr;
 use function strpos;
@@ -59,6 +61,10 @@ public function serialize($value): string
      */
     public function parseValue($value): DateTimeImmutable
     {
+        if (! is_string($value)) {
+            throw new InvalidArgumentException();
+        }
+
         if (! $this->validateDatetime($value)) {
             throw InvalidArgument::valueNotIso8601Compliant($value);
         }
@@ -67,18 +73,17 @@ public function parseValue($value): DateTimeImmutable
     }
 
     /**
-     * @param Node         $node
      * @param mixed[]|null $variables
      *
      * @phpcsSuppress SlevomatCodingStandard.TypeHints.ParameterTypeHint.MissingNativeTypeHint
      */
-    public function parseLiteral($node, ?array $variables = null): ?DateTimeImmutable
+    public function parseLiteral(Node $valueNode, ?array $variables = null): ?DateTimeImmutable
     {
-        if (! $node instanceof StringValueNode) {
+        if (! $valueNode instanceof StringValueNode) {
             return null;
         }
 
-        return $this->parseValue($node->value);
+        return $this->parseValue($valueNode->value);
     }
 
     private function validateDatetime(string $value): bool