Start using PHP CS Fixer

.gitignore

@@ -15,3 +15,6 @@ clover.xml
 
 # Ignore IDE's configuration files
 .idea
+
+# Ignore PHP CS Fixer cache
+.php_cs.cache

.travis.yml

@@ -56,6 +56,8 @@ before_install:
     STRIPE_MOCK_PID=$!
   - export PATH="${PATH}:${PWD}/stripe-mock/stripe-mock_${STRIPE_MOCK_VERSION}"
 
-script: ./build.php ${AUTOLOAD}
+script:
+  - ./build.php ${AUTOLOAD}
+  - ./vendor/bin/php-cs-fixer fix -v --dry-run --using-cache=no .
 
 after_script: ./vendor/bin/coveralls -v

.vscode/extensions.json

@@ -3,6 +3,7 @@
     "felixfbecker.php-intellisense",
     "ikappas.phpcs",
     "emallin.phpunit",
-    "EditorConfig.editorconfig"
+    "EditorConfig.editorconfig",
+    "sophisticode.php-formatter"
   ]
 }

.vscode/settings.json

@@ -6,6 +6,8 @@
 
   // Formatting
   "editor.formatOnSave": true,
+  "phpformatter.composer": true,
+  "phpformatter.arguments": [""],
 
   // Linting
   "phpcs.enable": true,

README.md

@@ -239,6 +239,12 @@ Update bundled CA certificates from the [Mozilla cURL release][curl]:
 ./update_certs.php
 ```
 
+The library uses [PHP CS Fixer][php-cs-fixer] for code formatting. Code must be formatted before PRs are submitted, otherwise CI will fail. Run the formatter with:
+
+```bash
+./vendor/bin/php-cs-fixer fix -v .
+```
+
 ## Attention plugin developers
 
 Are you writing a plugin that integrates Stripe and embeds our library? Then please use the `setAppInfo` function to identify your plugin. For example:
@@ -256,6 +262,7 @@ See the "SSL / TLS compatibility issues" paragraph above for full context. If yo
 [composer]: https://getcomposer.org/
 [connect]: https://stripe.com/connect
 [curl]: http://curl.haxx.se/docs/caextract.html
-[psr3]: http://www.php-fig.org/psr/psr-3/
 [idempotency-keys]: https://stripe.com/docs/api/php#idempotent_requests
+[php-cs-fixer]: https://github.com/FriendsOfPHP/PHP-CS-Fixer
+[psr3]: http://www.php-fig.org/psr/psr-3/
 [stripe-mock]: https://github.com/stripe/stripe-mock

composer.json

@@ -24,7 +24,8 @@
     "phpunit/phpunit": "^5.7",
     "php-coveralls/php-coveralls": "^2.1",
     "squizlabs/php_codesniffer": "^3.3",
-    "symfony/process": "~3.4"
+    "symfony/process": "~3.4",
+    "friendsofphp/php-cs-fixer": "^2.15"
   },
   "autoload": {
     "psr-4": { "Stripe\\" : "lib/" }