feat: add PHPStan level 5 with zero errors

- Install phpstan/phpstan, add phpstan.neon at level 5 targeting PHP 8.3
- Add phpstan-bootstrap.php stubs for Laravel helper functions (app,
  config, config_path, app_path, session) unavailable in standalone packages
- Fix CartCondition::setOrder() - removed incorrect @return int (method is void)
- Fix CartCondition::getCalculatedValue() - removed incorrect @return mixed PHPDoc
- Fix Cart::condition() - remove redundant instanceof check the type system already guarantees
- Fix Cart::fireEvent() - remove array_values() on already-list literal array
- Fix ItemCollection - add @property annotations for magic __get properties
- Fix ItemCollection::getAssociatedModel() - correct @return bool to @return mixed
- Fix ItemCollection::getConditions() - remove dead is_array && !instanceof check
- Fix Validator - add @method stub so PHPStan resolves make() through __callStatic
- Add ignoreErrors for trait.unused (HasCart designed for external Livewire use)
- Add ignoreErrors for round() mode mismatch (PHPStan 2.x PHP 8.4 stubs bug)
- Add phpstan step to CI (PHP 8.3 only, matches phpVersion config)

.github/workflows/tests.yml

@@ -37,3 +37,7 @@ jobs:
 
       - name: Execute tests
         run: vendor/bin/pest
+
+      - name: Static analysis
+        run: vendor/bin/phpstan analyse --no-progress
+        if: matrix.php == '8.3'

composer.json

@@ -30,7 +30,8 @@
     "mockery/mockery": "^2.0",
     "laravel/pint": "^1.21",
     "pestphp/pest": "^4.7",
-    "larapack/dd": "dev-master"
+    "larapack/dd": "dev-master",
+    "phpstan/phpstan": "2.2.x-dev"
   },
   "autoload": {
     "psr-4": {

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "36458db92bb67aee0a12a15f588349b4",
+    "content-hash": "56b40d3f17cc40f1b62c3f71a3601af7",
     "packages": [
         {
             "name": "brick/math",
@@ -6518,6 +6518,71 @@
             },
             "time": "2026-05-25T15:58:15+00:00"
         },
+        {
+            "name": "phpstan/phpstan",
+            "version": "2.2.x-dev",
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/5c0bbadd35255710f7d2402cd6213a0bc34cfa34",
+                "reference": "5c0bbadd35255710f7d2402cd6213a0bc34cfa34",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.4|^8.0"
+            },
+            "conflict": {
+                "phpstan/phpstan-shim": "*"
+            },
+            "default-branch": true,
+            "bin": [
+                "phpstan",
+                "phpstan.phar"
+            ],
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Ondřej Mirtes"
+                },
+                {
+                    "name": "Markus Staab"
+                },
+                {
+                    "name": "Vincent Langlet"
+                }
+            ],
+            "description": "PHPStan - PHP Static Analysis Tool",
+            "keywords": [
+                "dev",
+                "static analysis"
+            ],
+            "support": {
+                "docs": "https://phpstan.org/user-guide/getting-started",
+                "forum": "https://github.com/phpstan/phpstan/discussions",
+                "issues": "https://github.com/phpstan/phpstan/issues",
+                "security": "https://github.com/phpstan/phpstan/security/policy",
+                "source": "https://github.com/phpstan/phpstan-src"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/ondrejmirtes",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/phpstan",
+                    "type": "github"
+                }
+            ],
+            "time": "2026-06-05T16:36:10+00:00"
+        },
         {
             "name": "phpunit/php-code-coverage",
             "version": "12.5.x-dev",
@@ -8189,7 +8254,8 @@
     "aliases": [],
     "minimum-stability": "dev",
     "stability-flags": {
-        "larapack/dd": 20
+        "larapack/dd": 20,
+        "phpstan/phpstan": 20
     },
     "prefer-stable": false,
     "prefer-lowest": false,

phpstan-bootstrap.php

@@ -0,0 +1,42 @@
+<?php
+
+/**
+ * PHPStan bootstrap — stubs for Laravel global helpers that are always
+ * available at runtime in a Laravel application but are not present in the
+ * standalone illuminate/* packages this package depends on.
+ */
+
+if (! function_exists('app')) {
+    function app(string $abstract = null, array $parameters = []): mixed
+    {
+        return null;
+    }
+}
+
+if (! function_exists('config')) {
+    function config(string|null $key = null, mixed $default = null): mixed
+    {
+        return null;
+    }
+}
+
+if (! function_exists('config_path')) {
+    function config_path(string $path = ''): string
+    {
+        return '';
+    }
+}
+
+if (! function_exists('app_path')) {
+    function app_path(string $path = ''): string
+    {
+        return '';
+    }
+}
+
+if (! function_exists('session')) {
+    function session(string|array|null $key = null, mixed $default = null): mixed
+    {
+        return null;
+    }
+}

phpstan.neon

@@ -0,0 +1,14 @@
+parameters:
+    level: 5
+    phpVersion: 80300
+    paths:
+        - src
+    bootstrapFiles:
+        - phpstan-bootstrap.php
+    ignoreErrors:
+        # HasCart is a trait for external use in Livewire components — not used within this package.
+        - identifier: trait.unused
+        # PHPStan 2.x bundles PHP 8.4 stubs where PHP_ROUND_HALF_UP/DOWN map to 1/2 instead of 0/1.
+        # The code is correct at runtime on PHP 8.3. Remove once PHPStan stubs are corrected.
+        - message: '#Parameter \#3 \$mode of function round expects#'
+          path: src/Helpers/Helpers.php

src/Cart.php

@@ -342,10 +342,6 @@ public function condition(array|CartCondition $condition): self
             return $this;
         }
 
-        if (! $condition instanceof CartCondition) {
-            throw new InvalidConditionException('Argument 1 must be an instance of \'Wearepixel\Cart\CartCondition\'');
-        }
-
         $conditions = $this->getConditions();
 
         if ($condition->getOrder() === 0) {
@@ -735,6 +731,6 @@ protected function fireEvent(string $name, ?string $type = null, mixed $data = n
             $eventData[$type] = $data;
         }
 
-        return $this->events->dispatch('LaravelCart.' . $name, array_values([$eventData, $this]), true);
+        return $this->events->dispatch('LaravelCart.' . $name, [$eventData, $this], true);
     }
 }

src/CartCondition.php

@@ -105,13 +105,11 @@ public function setValue($value): void
     }
 
     /**
-     * Set the order to apply this condition. If no argument order is applied we return 0 as
-     * indicator that no assignment has been made
+     * Set the order to apply this condition.
      *
      * @param  int  $order
-     * @return int
      */
-    public function setOrder($order = 1)
+    public function setOrder($order = 1): void
     {
         $this->args['order'] = $order;
     }
@@ -139,8 +137,6 @@ public function applyCondition($totalOrSubTotalOrPrice)
 
     /**
      * get the calculated value of this condition supplied by the subtotal|price
-     *
-     * @return mixed
      */
     public function getCalculatedValue($totalOrSubTotalOrPrice = null): int|float
     {

src/ItemCollection.php

@@ -5,6 +5,14 @@
 use Illuminate\Support\Collection;
 use Wearepixel\Cart\Helpers\Helpers;
 
+/**
+ * @property mixed $id
+ * @property string $name
+ * @property float|int $price
+ * @property int|float $quantity
+ * @property array<string, mixed> $attributes
+ * @property mixed $conditions
+ */
 class ItemCollection extends Collection
 {
     /**
@@ -46,7 +54,7 @@ public function __get($name)
     /**
      * return the associated model of an item
      *
-     * @return bool
+     * @return mixed
      */
     protected function getAssociatedModel()
     {
@@ -97,7 +105,7 @@ public function getConditions()
 
         // check if we're already an array of CartConditions
         foreach ($conditions as $key => $condition) {
-            if ($condition instanceof CartCondition) {
+            if (is_object($condition) && $condition instanceof CartCondition) {
                 return $conditions;
             }
         }
@@ -105,7 +113,7 @@ public function getConditions()
         $hasSubArray = false;
 
         foreach ($conditions as $key => $condition) {
-            if (is_array($condition) && ! $condition instanceof CartCondition) {
+            if (is_array($condition)) {
                 $hasSubArray = true;
                 $conditionsArray[] = new CartCondition($condition);
             } elseif ($condition instanceof CartCondition) {

src/Validators/Validator.php

@@ -7,6 +7,9 @@
 use Illuminate\Translation\FileLoader;
 use Illuminate\Translation\Translator;
 
+/**
+ * @method static \Illuminate\Validation\Validator make(array $data, array $rules, array $messages = [], array $attributes = [])
+ */
 abstract class Validator
 {
     protected static $factory;