Check code style against PSR-12

Author: colinodell

.gitattributes

@@ -5,6 +5,7 @@
 /.gitattributes       export-ignore
 /.github              export-ignore
 /.gitignore           export-ignore
+/phpcs.xml.dist       export-ignore
 /phpstan.neon.dist    export-ignore
 /phpunit.xml.dist     export-ignore
 /psalm.xml.dist       export-ignore

.github/workflows/tests.yml

@@ -5,6 +5,24 @@ on:
     pull_request: ~
 
 jobs:
+    phpcs:
+        name: PHPCS
+        runs-on: ubuntu-latest
+
+        steps:
+            - uses: actions/checkout@v2
+
+            - uses: shivammathur/setup-php@v2
+              with:
+                  php-version: 7.1
+                  extensions: curl, mbstring
+                  coverage: none
+                  tools: composer:v2, cs2pr
+
+            - run: composer update --no-progress
+
+            - run: vendor/bin/phpcs -q --report=checkstyle | cs2pr
+
     phpunit:
         name: PHPUnit on ${{ matrix.php }} ${{ matrix.composer-flags }}
         runs-on: ubuntu-latest

.gitignore

@@ -1,5 +1,7 @@
+.phpcs-cache
 .phpunit.result.cache
 composer.lock
+phpcs.xml
 phpstan.neon
 phpunit.xml
 psalm.xml

composer.json

@@ -28,6 +28,7 @@
     "require-dev": {
         "phpstan/phpstan": "^0.12.42",
         "phpunit/phpunit": "^7.5 || ^8.5 || ^9.3",
+        "squizlabs/php_codesniffer": "^3.5",
         "vimeo/psalm": "^3.14"
     },
     "autoload": {

phpcs.xml.dist

@@ -0,0 +1,17 @@
+<?xml version="1.0"?>
+<ruleset>
+    <arg name="basepath" value="."/>
+    <arg name="extensions" value="php"/>
+    <arg name="parallel" value="80"/>
+    <arg name="cache" value=".phpcs-cache"/>
+    <arg name="colors"/>
+
+    <!-- Ignore warnings, show progress of the run and show sniff names -->
+    <arg value="nps"/>
+
+    <!-- Directories to be checked -->
+    <file>src</file>
+    <file>tests</file>
+
+    <rule ref="PSR12"/>
+</ruleset>