Add PHP CS fixer

.github/workflows/lint-php.yaml

@@ -0,0 +1,28 @@
+---
+name: Lint
+on:
+  - push
+  - pull_request
+
+jobs:
+  xml-linters:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@master
+      - name: Download schema
+        run: wget https://apps.nextcloud.com/schema/apps/info.xsd
+      - name: Lint info.xml
+        uses: ChristophWurst/xmllint-action@v1
+        with:
+          xml-file: ./appinfo/info.xml
+          xml-schema-file: ./info.xsd
+  php-cs-fixer:
+    name: PHP-CS-Fixer
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: PHP-CS-Fixer
+        uses: docker://oskarstark/php-cs-fixer-ga
+        with:
+          args: --dry-run --diff lib

.gitignore

@@ -18,6 +18,7 @@ js/
 build/
 coverage/
 .php_cs.cache
+.php-cs-fixer.cache
 vendor
 memories.tar.gz
 /test-results/

.php-cs-fixer.php

@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of PHP CS Fixer.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *     Dariusz Rumiński <dariusz.ruminski@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+$finder = PhpCsFixer\Finder::create()
+    ->ignoreDotFiles(false)
+    ->ignoreVCSIgnored(true)
+    ->exclude('tests/Fixtures')
+    ->in(__DIR__)
+    ->append([
+        __DIR__.'/dev-tools/doc.php',
+        // __DIR__.'/php-cs-fixer', disabled, as we want to be able to run bootstrap file even on lower PHP version, to show nice message
+    ])
+;
+
+$config = new PhpCsFixer\Config();
+$config
+    ->setRiskyAllowed(true)
+    ->setRules([
+        '@PHP71Migration' => false,
+        '@PHP71Migration:risky' => false,
+        '@PHPUnit75Migration:risky' => true,
+        '@PhpCsFixer' => true,
+        '@PhpCsFixer:risky' => true,
+        'general_phpdoc_annotation_remove' => ['annotations' => ['expectedDeprecation']], // one should use PHPUnit built-in method instead
+        'modernize_strpos' => false, // needs PHP 8+ or polyfill
+    ])
+    ->setFinder($finder)
+;
+
+// special handling of fabbot.io service if it's using too old PHP CS Fixer version
+if (false !== getenv('FABBOT_IO')) {
+    try {
+        PhpCsFixer\FixerFactory::create()
+            ->registerBuiltInFixers()
+            ->registerCustomFixers($config->getCustomFixers())
+            ->useRuleSet(new PhpCsFixer\RuleSet($config->getRules()))
+        ;
+    } catch (PhpCsFixer\ConfigurationException\InvalidConfigurationException $e) {
+        $config->setRules([]);
+    } catch (UnexpectedValueException $e) {
+        $config->setRules([]);
+    } catch (InvalidArgumentException $e) {
+        $config->setRules([]);
+    }
+}
+
+return $config;