Introduce PHPCS

.gitignore

@@ -1,5 +1,4 @@
-.idea/
 composer.phar
 composer.lock
+phpcs.xml
 vendor/
-bin/

.travis.yml

@@ -2,8 +2,6 @@ dist: trusty
 language: php
 
 php:
-    - 5.6
-    - 7.0
     - 7.1
     - 7.2
     - nightly
@@ -47,3 +45,21 @@ jobs:
       after_script:
         - wget https://scrutinizer-ci.com/ocular.phar
         - php ocular.phar code-coverage:upload --format=php-clover clover.xml
+    - stage: Pull request coding standard
+      if: type = pull_request
+      install: travis_retry composer install --prefer-dist
+      script:
+        - |
+          if [ $TRAVIS_BRANCH != "master" ]; then
+            git remote set-branches --add origin $TRAVIS_BRANCH;
+            git fetch origin $TRAVIS_BRANCH;
+          fi
+        - git merge-base origin/$TRAVIS_BRANCH $TRAVIS_PULL_REQUEST_SHA || git fetch origin +refs/pull/$TRAVIS_PULL_REQUEST/merge --unshallow
+        - wget https://github.com/diff-sniffer/git/releases/download/0.1.0/git-phpcs.phar
+        - php git-phpcs.phar origin/$TRAVIS_BRANCH...$TRAVIS_PULL_REQUEST_SHA
+    - stage: Coding standard
+      if: NOT type = pull_request
+      php: 7.1
+      install: travis_retry composer install --prefer-dist
+      script:
+        - ./vendor/bin/phpcs

composer.json

@@ -9,10 +9,11 @@
     "API"
   ],
   "require": {
-    "php": ">=5.6",
+    "php": "^7.1",
     "ext-mbstring": "*"
   },
   "require-dev": {
+    "doctrine/coding-standard": "^4.0",
     "phpunit/phpunit": "^4.8",
     "psr/http-message": "^1.0"
   },

phpcs.xml.dist

@@ -0,0 +1,93 @@
+<?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" />
+
+    <file>src</file>
+    <file>tests</file>
+
+    <rule ref="Doctrine">
+        <!--Disable PHP7+ features that might cause BC breaks for now -->
+        <exclude name="SlevomatCodingStandard.Classes.ClassConstantVisibility.MissingConstantVisibility" />
+        <exclude name="SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint" />
+        <exclude name="SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint" />
+    </rule>
+
+    <!--@api annotation is required for now -->
+    <rule ref="SlevomatCodingStandard.TypeHints.TypeHintDeclaration">
+        <properties>
+            <property
+                    name="usefulAnnotations"
+                    type="array"
+                    value="
+                    @after,
+                    @afterClass,
+                    @AfterMethods,
+                    @api,
+                    @Attribute,
+                    @Attributes,
+                    @before,
+                    @beforeClass,
+                    @BeforeMethods,
+                    @covers,
+                    @coversDefaultClass,
+                    @coversNothing,
+                    @dataProvider,
+                    @depends,
+                    @deprecated,
+                    @doesNotPerformAssertions,
+                    @Enum,
+                    @expectedDeprecation,
+                    @expectedException,
+                    @expectedExceptionCode,
+                    @expectedExceptionMessage,
+                    @expectedExceptionMessageRegExp,
+                    @group,
+                    @Groups,
+                    @IgnoreAnnotation,
+                    @internal,
+                    @Iterations,
+                    @link,
+                    @ODM\,
+                    @ORM\,
+                    @requires,
+                    @Required,
+                    @Revs,
+                    @runInSeparateProcess,
+                    @runTestsInSeparateProcesses,
+                    @see,
+                    @Target,
+                    @test,
+                    @throws,
+                    @uses
+                "
+            />
+        </properties>
+    </rule>
+
+    <rule ref="SlevomatCodingStandard.Commenting.ForbiddenAnnotations">
+        <properties>
+            <property
+                    name="forbiddenAnnotations"
+                    type="array"
+                    value="
+                    @author,
+                    @category,
+                    @copyright,
+                    @created,
+                    @license,
+                    @package,
+                    @since,
+                    @subpackage,
+                    @version
+                "
+            />
+        </properties>
+    </rule>
+</ruleset>