Add coding-standard rules with PHP-CS-Fixer

.gitignore

@@ -14,6 +14,9 @@ composer.phar
 composer.lock
 vendor
 
+# PHP-CS-Fixer related
+.php_cs.cache
+
 # javascript dependencies
 plugins/enigma/openpgp.min.js
 plugins/managesieve/codemirror/

.php_cs

@@ -0,0 +1,37 @@
+<?php
+return PhpCsFixer\Config::create()
+    ->setRiskyAllowed(true)
+    ->setRules([
+        '@Symfony' => true,
+        '@Symfony:risky' => true,
+        'array_syntax' => ['syntax' => 'long'],
+        'binary_operator_spaces' => false,
+        'concat_space' => ['spacing' => 'one'],
+        'heredoc_to_nowdoc' => true,
+        'method_argument_space' => true,
+        'modernize_types_casting' => false,
+        'no_extra_consecutive_blank_lines' => ['break', 'continue', 'extra', 'return', 'throw', 'use', 'parenthesis_brace_block', 'square_brace_block', 'curly_brace_block'],
+        'no_php4_constructor' => true,
+        'no_short_echo_tag' => true,
+        'no_unreachable_default_argument_value' => true,
+        'no_useless_else' => true,
+        'no_useless_return' => true,
+        'ordered_imports' => true,
+        'php_unit_fqcn_annotation' => false,
+        'phpdoc_add_missing_param_annotation' => true,
+        'phpdoc_order' => true,
+        'phpdoc_summary' => false,
+        'phpdoc_trim' => false,
+        'semicolon_after_instruction' => true,
+        'simplified_null_return' => true,
+        'single_quote' => false,
+        'yoda_style' => false,
+    ])
+    ->setFinder(
+        PhpCsFixer\Finder::create()
+            ->in(__DIR__ . '/installer')
+            ->in(__DIR__ . '/plugins')
+            ->in(__DIR__ . '/program')
+            ->in(__DIR__ . '/tests')
+    )
+;

.travis.yml

@@ -9,6 +9,7 @@ matrix:
     - php: 5.5
     - php: 5.6
     - php: 7.0
+      env: CS_CHECK=1
     - php: 7.1
       env: CODE_COVERAGE=1
     - php: 7.2
@@ -20,10 +21,12 @@ cache:
 install:
   - if [ "$CODE_COVERAGE" != 1 ]; then phpenv config-rm xdebug.ini || true; fi
   - cp composer.json-dist composer.json
+  - if [ "$CS_CHECK" != 1 ]; then composer remove --no-update --no-scripts --dev friendsofphp/php-cs-fixer; fi
   - composer install --prefer-dist
 
 script:
   - if [ "$CODE_COVERAGE" = 1 ]; then CODE_COVERAGE_ARGS="--coverage-text"; fi; vendor/bin/phpunit -c tests/phpunit.xml $CODE_COVERAGE_ARGS
+  - if [ "$CS_CHECK" = 1 ]; then vendor/bin/php-cs-fixer fix --diff --dry-run --verbose; fi
 
 notifications:
   email: false

composer.json-dist

@@ -22,6 +22,7 @@
         "endroid/qrcode": "~1.6.5"
     },
     "require-dev": {
+        "friendsofphp/php-cs-fixer": "^2.2",
         "phpunit/phpunit": "^4.8.36 || ^5.7.21"
     },
     "suggest": {