test: Add mutation testing configuration and update composer dev-dependencies

Author: roxblnfk

.github/workflows/infection.yml

@@ -0,0 +1,65 @@
+---
+
+name: 🧬 Mutation testing
+
+on:  # yamllint disable-line rule:truthy
+  pull_request:
+    branches:
+      - 1.x
+    paths:
+      - 'src/**'
+      - 'tests/**'
+      - 'infection.json'
+      - 'testo.php'
+      - 'composer.json'
+      - 'composer.lock'
+      - '.github/workflows/infection.yml'
+  push:
+    branches:
+      - 1.x
+    paths:
+      - 'src/**'
+      - 'tests/**'
+      - 'infection.json'
+      - 'testo.php'
+      - 'composer.json'
+      - 'composer.lock'
+      - '.github/workflows/infection.yml'
+
+jobs:
+  infection:
+    timeout-minutes: 4
+    runs-on: ${{ matrix.os }}
+    concurrency:
+      cancel-in-progress: true
+      group: infection-${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}-${{ matrix.php-version }}-${{ matrix.dependencies }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+        php-version:
+          - '8.5'
+        dependencies:
+          - highest
+    name: 🧬 Infection PHP${{ matrix.php-version }}
+    steps:
+      - name: 📦 Check out the codebase
+        uses: actions/checkout@v6
+
+      - name: 🛠️ Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          coverage: xdebug
+          ini-values: error_reporting=E_ALL
+
+      - name: 📥 Install dependencies with composer
+        uses: ramsey/composer-install@v3
+        env:
+          COMPOSER_ROOT_VERSION: '1.x-dev'
+        with:
+          dependency-versions: ${{ matrix.dependencies }}
+
+      - name: 🧬 Run Infection
+        run: composer infect:ci

.gitmodules

@@ -30,10 +30,13 @@
     },
     "require-dev": {
         "buggregator/trap": "^1.15",
-        "spiral/code-style": "^2.3.1",
+        "infection/infection": "^0.33.2",
+        "llm/skills": "^1.7",
         "roxblnfk/unpoly": "^1.8.1",
-        "vimeo/psalm": "^6.13",
-        "testo/testo": "^0.10.20"
+        "spiral/code-style": "^2.3.1",
+        "testo/bridge-infection": "^0.1.6",
+        "testo/testo": "^0.10.21",
+        "vimeo/psalm": "^7"
     },
     "minimum-stability": "dev",
     "prefer-stable": true,
@@ -47,16 +50,19 @@
             "Internal\\Path\\Tests\\": "tests/"
         }
     },
+    "config": {
+        "sort-packages": true,
+        "allow-plugins": {
+            "infection/extension-installer": true,
+            "llm/skills": true
+        }
+    },
     "scripts": {
         "cs:diff": "php-cs-fixer fix --dry-run -v --diff",
         "cs:fix": "php-cs-fixer fix -v",
-        "infect": [
-            "@putenv XDEBUG_MODE=coverage",
-            "roave-infection-static-analysis-plugin --configuration=infection.json.dist"
-        ],
+        "infect": "infection --configuration=infection.json --threads=max",
         "infect:ci": [
-            "@putenv XDEBUG_MODE=coverage",
-            "roave-infection-static-analysis-plugin --ansi --configuration=infection.json.dist --logger-github --ignore-msi-with-no-mutations --only-covered"
+            "infection --ansi --configuration=infection.json --logger-github --threads=max --show-mutations=0"
         ],
         "psalm": "psalm",
         "psalm:baseline": "psalm --set-baseline=psalm-baseline.xml",

composer.json

@@ -0,0 +1,9 @@
+{
+    "$schema": "vendor/infection/infection/resources/schema.json",
+    "source": {
+        "directories": [
+            "src"
+        ]
+    },
+    "testFramework": "testo"
+}

infection.json

@@ -38,6 +38,7 @@ final class Path implements \Stringable
     /**
      * @param non-empty-string $path The filesystem path. In never ends with a separator.
      *        Might be ended with "." or ".." if the path is a directory.
+     * @psalm-mutation-free
      */
     private function __construct(
         private readonly string $path,
@@ -46,6 +47,9 @@ private function __construct(
 
     /**
      * Create a new path object
+     *
+     * @psalm-pure
+     * @psalm-mutation-free
      */
     public static function create(self|string $path = ''): self
     {
@@ -58,6 +62,7 @@ public static function create(self|string $path = ''): self
      * Join this path with one or more path components
      *
      * @psalm-immutable
+     * @psalm-mutation-free
      */
     public function join(self|string ...$paths): self
     {
@@ -88,6 +93,7 @@ public function join(self|string ...$paths): self
      * Return the file or directory name (the final path component)
      *
      * @return non-empty-string
+     * @psalm-mutation-free
      */
     public function name(): string
     {
@@ -101,6 +107,7 @@ public function name(): string
      * Return the file stem (the file name without its extension)
      *
      * @return non-empty-string
+     * @psalm-mutation-free
      */
     public function stem(): string
     {
@@ -111,6 +118,8 @@ public function stem(): string
 
     /**
      * Return the file suffix (extension) without the leading dot
+     *
+     * @psalm-mutation-free
      */
     public function extension(): string
     {
@@ -123,6 +132,7 @@ public function extension(): string
      * Return the parent directory path
      *
      * @psalm-immutable
+     * @psalm-mutation-free
      */
     public function parent(): self
     {
@@ -152,6 +162,8 @@ public function parent(): self
 
     /**
      * Return whether this path is absolute
+     *
+     * @psalm-mutation-free
      */
     public function isAbsolute(): bool
     {
@@ -160,6 +172,8 @@ public function isAbsolute(): bool
 
     /**
      * Return whether this path is relative
+     *
+     * @psalm-mutation-free
      */
     public function isRelative(): bool
     {