When contributing code to Symfony2, you must follow its coding standards. To make a long story short, here is the golden rule: Imitate the existing Symfony2 code.
- Never use short tags (<?);
- Don't end class files with the usual ?> closing tag;
- Indentation is done by steps of four spaces (tabs are never allowed);
- Use the linefeed character (0x0A) to end lines;
- Add a single space after each comma delimiter;
- Don't put spaces after an opening parenthesis and before a closing one;
- Add a single space around operators (==, &&, ...);
- Add a single space before the opening parenthesis of a control keyword (if, else, for, while, ...);
- Add a blank line before return statements;
- Don't add trailing spaces at the end of lines;
- Use braces to indicate control structure body regardless of the number of statements it contains;
- Put braces on their own line for classes, methods, and functions declaration;
- Separate the conditional statement and the opening brace with a single space and no blank line;
- Declare visibility explicitly for class, methods, and properties (usage of var is prohibited);
- Use lowercase PHP native typed constants: false, true, and null. The same goes for array();
- Use uppercase strings for constants with words separated with underscores;
- Define one class per file;
- Declare class properties before methods;
- Declare public methods first, then protected ones and finally private ones.
- Use camelCase, not underscores, for variable, function and method names;
- Use underscores for option, argument, parameter names;
- Use namespaces for all classes;
- Use Symfony as the first namespace level;
- Suffix interfaces with Interface;
- Use alphanumeric characters and underscores for file names;
- Add PHPDoc blocks for all classes, methods, and functions;
- The @package and @subpackage annotations are not used.