Replace PHP_CodeSniffer with PHP-CS-Fixer

.gitattributes

@@ -1,7 +1,7 @@
 /tests export-ignore
 /.gitattributes export-ignore
 /.gitignore export-ignore
-/phpcs.xml.dist export-ignore
+/.php-cs-fixer.php export-ignore
 /psalm.xml.dist export-ignore
 /README.md export-ignore
 /.github export-ignore

.github/workflows/ci.yml

@@ -54,7 +54,7 @@ jobs:
             - name: Run Psalm
               run: vendor/bin/psalm --output-format=github --shepherd
 
-    phpcs:
+    php-cs-fixer:
         name: Code style
         runs-on: ubuntu-latest
         steps:
@@ -91,8 +91,8 @@ jobs:
               env:
                   COMPOSER_ROOT_VERSION: dev-master
 
-            - name: Run PHPCodeSniffer
-              run: vendor/bin/phpcs --report=checkstyle -q --parallel=1 | cs2pr
+            - name: Run PHP-CS-Fixer
+              run: vendor/bin/php-cs-fixer check --format=checkstyle | cs2pr
 
     test-static-analysis:
         name: Run static analysis on the tests themselves

.gitignore

@@ -2,3 +2,4 @@
 composer.lock
 vendor
 .claude/settings.local.json
+/.php-cs-fixer.cache

.php-cs-fixer.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+use PhpCsFixer\Config;
+use PhpCsFixer\Finder;
+use PhpCsFixer\Runner\Parallel\ParallelConfigFactory;
+
+return (new Config())
+    ->setUnsupportedPhpVersionAllowed(true)
+    ->setRiskyAllowed(false)
+    ->setRules([
+        '@PER-CS3x0' => true,
+        // import
+        'global_namespace_import' => [
+            'import_classes' => false,
+            'import_constants' => false,
+            'import_functions' => false,
+        ],
+        'no_unused_imports' => true,
+        'ordered_imports' => true,
+    ])
+    ->setFinder(
+        (new Finder())
+            ->in([
+                __DIR__ . '/src',
+                __DIR__ . '/tools/behat',
+            ])
+            ->name('*.php')
+            ->exclude(['vendor', 'run'])
+            ->append([
+                __FILE__,
+            ]),
+    )
+    ->setParallelConfig(ParallelConfigFactory::detect());

AGENTS.md

@@ -56,7 +56,7 @@ These come first, before every other rule here:
 CI (`.github/workflows/ci.yml`) is the source of truth:
 - `psalm` (PHP 8.2): `COMPOSER_ROOT_VERSION=dev-master composer update --prefer-dist`, then
   `vendor/bin/psalm --output-format=github --shepherd` on `src/`.
-- `phpcs`: `vendor/bin/phpcs`. `composer check` runs phpcs and Psalm.
+- `php-cs-fixer`: `vendor/bin/php-cs-fixer check --diff`. `composer check` runs PHP-CS-Fixer and Psalm.
 - `test-static-analysis` (PHP 8.2): `cd tools/behat && composer install && vendor/bin/psalm`, then
   `php tools/behat/lint-features.php` (see "Tests").
 - `tests`: deps high/low/stable × PHP 8.2 and 8.4 on pull requests, PHP 8.2 to 8.4 on pushes,
@@ -83,8 +83,8 @@ Locally:
     nothing ("No scenarios"). Check that the output says `1 scenario`.
 - The full suite (a few minutes) at most once, right before pushing. Never between
   iterations, and never sweeps (re-running batches of scenarios, looping over fixtures).
-- `vendor/bin/phpcs -q`, `vendor/bin/psalm --no-cache` (~2 s) and `php tools/behat/lint-features.php` are cheap
-  and fine at any time.
+- `vendor/bin/php-cs-fixer check`, `vendor/bin/psalm --no-cache` (~2 s) and
+  `php tools/behat/lint-features.php` are cheap and fine at any time.
 - Also fine: a scratch-project repro (skill `plugin-repro`).
 - When briefing a subagent, spell all of this out ("single scenarios only, no full suite,
   no sweeps"); a vague "don't run the tests" is not enough.
@@ -209,9 +209,8 @@ workaround explicitly in the report.
 
 ## Code style
 
-- phpcs (`phpcs.xml.dist`): PSR12, short arrays, 120-character absolute line limit, applied
-  to `src/`. Run `vendor/bin/phpcs`
-  (`vendor/bin/phpcbf` fixes).
+- PHP-CS-Fixer (`.php-cs-fixer.php`): PER-CS 3.0, applied to `src/` and `tools/behat/`. Run
+  `vendor/bin/php-cs-fixer check --diff` (`vendor/bin/php-cs-fixer fix` fixes).
 - Match the surrounding code: comment density, naming, idiom.
 - Comments are concise and only explain what isn't obvious from the code:
   - don't restate the code in prose;

composer.json

@@ -15,9 +15,9 @@
         "vimeo/psalm": "^7.2 || dev-master"
     },
     "require-dev": {
+        "friendsofphp/php-cs-fixer": "^3.88",
         "phpspec/prophecy-phpunit": "^2.5",
-        "phpunit/phpunit": "^11.0 || ^12.0 || ^13.0",
-        "squizlabs/php_codesniffer": "^3.13"
+        "phpunit/phpunit": "^11.0 || ^12.0 || ^13.0"
     },
     "conflict": {
         "phpspec/prophecy": "<1.20.0",
@@ -48,7 +48,7 @@
             "@cs-check",
             "@analyze"
         ],
-        "cs-check": "phpcs",
-        "cs-fix": "phpcbf"
+        "cs-check": "php-cs-fixer check --diff",
+        "cs-fix": "php-cs-fixer fix"
     }
 }