Add static analysis tool

.gitignore

@@ -2,3 +2,5 @@ composer.phar
 composer.lock
 phpcs.xml
 vendor/
+bin/
+phpstan.phar

.travis.yml

@@ -6,10 +6,6 @@ php:
   - 7.2
   - nightly
 
-matrix:
-  allow_failures:
-    - php: nightly
-
 cache:
   directories:
     - $HOME/.composer/cache
@@ -18,12 +14,9 @@ before_install:
   - mv ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/xdebug.ini{,.disabled} || echo "xdebug not available"
   - travis_retry composer self-update
 
-install:
+install: composer install --dev --prefer-dist
-  - composer require react/promise:2.*
-  - composer require psr/http-message:1.*
-  - travis_retry composer update --prefer-dist
 
-script: ./vendor/bin/phpunit --group default,ReactPromise
+script: bin/phpunit --group default,ReactPromise
 
 jobs:
   allow_failures:
@@ -41,13 +34,19 @@ jobs:
         - mv ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/xdebug.ini{.disabled,}
         - if [[ ! $(php -m | grep -si xdebug) ]]; then echo "xdebug required for coverage"; exit 1; fi
       script:
-        - ./vendor/bin/phpunit --coverage-clover clover.xml
+        - bin/phpunit --coverage-clover clover.xml
       after_script:
         - wget https://scrutinizer-ci.com/ocular.phar
         - php ocular.phar code-coverage:upload --format=php-clover clover.xml
 
-    - stage: Coding standard
+    - stage: Code Quality
       php: 7.1
       install: travis_retry composer install --prefer-dist
       script:
         - ./vendor/bin/phpcs
+
+    - stage: Code Quality
+      php: 7.2
+      env: STATIC_ANALYSIS
+      install: travis_retry composer install --prefer-dist
+      script: composer static-analysis

composer.json

@@ -16,9 +16,12 @@
   "require-dev": {
     "doctrine/coding-standard": "^4.0",
     "phpunit/phpunit": "^7.2",
-    "psr/http-message": "^1.0"
+    "phpstan/phpstan-shim": "^0.10",
+    "psr/http-message": "^1.0",
+    "react/promise": "2.*"
   },
   "config": {
+    "bin-dir": "bin",
     "preferred-install": "dist",
     "sort-packages": true
 },
@@ -39,6 +42,7 @@
     "psr/http-message": "To use standard GraphQL server"
   },
   "scripts": {
-    "lint" : "phpcs"
+    "lint" : "phpcs",
+    "static-analysis": "@php bin/phpstan.phar analyse --ansi -l 1 -c phpstan.neon src"
   }
 }

src/Executor/Promise/Promise.php

@@ -6,6 +6,7 @@ namespace GraphQL\Executor\Promise;
 
 use GraphQL\Executor\Promise\Adapter\SyncPromise;
 use GraphQL\Utils\Utils;
+use React\Promise\Promise as ReactPromise;
 
 /**
  * Convenience wrapper for promises represented by Promise Adapter

src/Language/Visitor.php

@@ -264,6 +264,7 @@ class Visitor
 
                 if ($visitFn) {
                     $result = call_user_func($visitFn, $node, $key, $parent, $path, $ancestors);
+                    $editValue = null;
 
                     if ($result !== null) {
                         if ($result instanceof VisitorOperation) {

src/Server/StandardServer.php

@@ -8,7 +8,7 @@ use GraphQL\Error\FormattedError;
 use GraphQL\Error\InvariantViolation;
 use GraphQL\Executor\ExecutionResult;
 use GraphQL\Executor\Promise\Promise;
-use GraphQL\Utils;
+use GraphQL\Utils\Utils;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
 use Psr\Http\Message\StreamInterface;

src/Validator/Rules/KnownDirectives.php

@@ -7,7 +7,9 @@ namespace GraphQL\Validator\Rules;
 use GraphQL\Error\Error;
 use GraphQL\Language\AST\DirectiveNode;
 use GraphQL\Language\AST\InputObjectTypeDefinitionNode;
+use GraphQL\Language\AST\Node;
 use GraphQL\Language\AST\NodeKind;
+use GraphQL\Language\AST\NodeList;
 use GraphQL\Language\DirectiveLocation;
 use GraphQL\Validator\ValidationContext;
 use function count;
@@ -59,7 +61,9 @@ class KnownDirectives extends ValidationRule
     }
 
     /**
-     * @param (Node|NodeList)[] $ancestors
+     * @param Node[]|NodeList[] $ancestors
+     *
+     * @return string
      */
     private function getDirectiveLocationForASTPath(array $ancestors)
     {

src/Validator/Rules/VariablesDefaultValueAllowed.php

@@ -44,10 +44,10 @@ class VariablesDefaultValueAllowed extends ValidationRule
 
                 return Visitor::skipNode();
             },
-            NodeKind::SELECTION_SET       => function (SelectionSetNode $node) use ($context) {
+            NodeKind::SELECTION_SET       => function (SelectionSetNode $node) {
                 return Visitor::skipNode();
             },
-            NodeKind::FRAGMENT_DEFINITION => function (FragmentDefinitionNode $node) use ($context) {
+            NodeKind::FRAGMENT_DEFINITION => function (FragmentDefinitionNode $node) {
                 return Visitor::skipNode();
             },
         ];