Coding Standard

Standards

As of May 2014, Vanilla will adhere to PSR-2 (and therefore PSR-1) with a few exceptions. We have been mass-updating our source code as possible without breaking backwards compatibility (most notably by refraining from changing the casing of existing variables).

We’ve named our primary exception to PSR-2 the Lord Brackos rule - Same-line open braces on all classes, method, and function definitions.

We adopted this standard for all the usual reasons: our team is growing, and we want to make sure things stay consistent between our various projects, and it’s annoying and hard to read when everything is styled differently. Key words in this document (“MUST”, “SHOULD”, etc.) are used as described in RFC 2119 which is as boring and obvious as you expect but mercifully brief.

PHP Version

All code in master must work under PHP 5.6, but we strongly recommend using 7.0.

All code in release/2.3 must work under PHP 5.4.

For up-to-date information you can look at our self-hosting-requirements section.

Validating your PHP code with PHP_CodeSniffer

CodeSniffer is a tool you can plug into your IDE to help you adhere to a coding standard like this one. This quick guide assumes you have both PEAR and homebrew with PHP 5.5 installed.

Our standard is in Vanilla’s Standards repo, where you can submit issues and pull requests. Its contents will help you on your way.

  1. Get CodeSniffer: pear install PHP_CodeSniffer.
  2. Add to bash profile: export PATH="$(brew --prefix php55)/bin:$PATH".
  3. Find CodeSniffer’s Standards folder. Use pear config-get php_dir and go from there.
  4. Symlink standards/code-sniffer/Vanilla to CodeSniffer’s Standards folder.
  5. Set Vanilla as your standard: phpcs --config-set default_standard Vanilla.
  6. Use it: phpcs /path/to/code.

Thus ends the readable part of your adventure as you descend into the dry, technical blather of a coding standard. Godspeed, coding warrior.

1. Overview

  • Code MUST use 4 spaces for indenting, not tabs.

  • Opening braces for classes and functions SHOULD be on the same line.

  • Control structure keywords MUST have one space after them; method and function calls MUST NOT.

  • Opening braces for control structures MUST go on the same line, and closing braces MUST go on the next line after the body.

  • Opening parentheses for control structures MUST NOT have a space after them, and closing parentheses for control structures MUST NOT have a space before.

  • There MUST NOT be a hard limit on line length; the soft limit MUST be 120 characters; lines SHOULD be 80 characters or less.

  • Namespace is not required.

  • Files MUST use only <?php tag.

  • Files MUST use only UTF-8 without BOM for PHP code.

  • Files SHOULD either declare symbols (classes, functions, constants, etc.) or cause side-effects (e.g. generate output, change .ini settings, etc.) but SHOULD NOT do both.

  • Class names MUST be declared in StudlyCaps.

  • Class constants MUST be declared in all upper case with underscore separators.

  • Method names SHOULD be declared in camelCase.

  • View files are excluded from this standard. You SHOULD try to follow as many rules as possible.

1.1. Example

This example encompasses some of the rules below as a quick overview:

<?php
/**
 * @copyright 2009-2014 Vanilla Forums Inc.
 * @license http://www.opensource.org/licenses/gpl-2.0.php GPLv2
 */

/**
 * The is the foo class that does foo.
 *
 * This is a longer description that spans multiple
 * lines.
 */
class Foo extends Bar implements FooInterface {
    /**
     * The is the foo class that does foo.
     *
     * This is a longer description that spans multiple
     * lines.
     *
     * @param string $a Must be a full sentence.
     * @param string|null $b Must be a full sentence.
     *
     * @return bool
     */
    public function sampleFunction($a, $b = null) {
        if ($a === $b) {
            bar();
        } elseif ($a > $b) {
            $foo->bar($arg1);
        } else {
            BazClass::bar($arg2, $arg3);
        }

        return true;
    }


}

2. General

2.1. Files

All PHP files MUST use the Unix LF (linefeed) line ending.

All PHP files MUST end with a single blank line.

The closing ?> tag MUST be omitted from files containing only PHP.

All view files are excluded from this standard. You SHOULD try to follow as many rules as possible.

2.2. PHP Tags

PHP code MUST use the long <?php ?> tags; it MUST NOT use the other tag variations.

2.3. Character Encoding

PHP code MUST use only UTF-8 without BOM.

2.4. Side Effects

A file SHOULD declare new symbols (classes, functions, constants, etc.) and cause no other side effects, or it SHOULD execute logic with side effects, but SHOULD NOT do both.

The phrase “side effects” means execution of logic not directly related to declaring classes, functions, constants, etc., merely from including the file.

“Side effects” include but are not limited to: generating output, explicit use of require or include, connecting to external services, modifying ini settings, emitting errors or exceptions, modifying global or static variables, reading from or writing to a file, and so on.

The following is an example of a file with both declarations and side effects; i.e, an example of what to avoid:

<?php
// side effect: change ini settings
ini_set('error_reporting', E_ALL);

// side effect: loads a file
include "file.php";

// side effect: generates output
echo "<html>\n";

// declaration
function foo() {
    // function body
}

The following example is of a file that contains declarations without side effects; i.e., an example of what to emulate:

<?php
// declaration
function foo() {
    // function body
}

// conditional declaration is *not* a side effect
if (! function_exists('bar')) {
    function bar() {
        // function body
    }
}

2.5. Lines

There MUST NOT be a hard limit on line length.

The soft limit on line length MUST be 120 characters; automated style checkers MUST warn but MUST NOT error at the soft limit.

Lines SHOULD NOT be longer than 80 characters; lines longer than that SHOULD be split into multiple subsequent lines of no more than 80 characters each.

There MUST NOT be trailing whitespace at the end of non-blank lines.

Blank lines MAY be added to improve readability and to indicate related blocks of code.

There MUST NOT be more than one statement per line.

2.6. Indenting

Code MUST use an indent of 4 spaces, and MUST NOT use tabs for indenting.

2.7. Keywords and True/False/Null

PHP keywords MUST be in lower case.

The PHP constants true, false, and null MUST be in lower case.

3. Namespace and Use Declarations

No requirements.

4. Class Constants, Properties, and Methods

The term “class” refers to all classes, interfaces, and traits.

4.1. Constants

Class constants MUST be declared in all upper case with underscore separators. For example:

<?php
namespace Vendor\Model;

class Foo {
    const VERSION = '1.0';
    const DATE_APPROVED = '2012-06-01';
}

4.2. Extends and Implements

The extends and implements keywords MUST be declared on the same line as the class name.

The opening brace for the class MUST go on the same line as the class name; the closing brace for the class MUST go on the next line after the body.

<?php

class ClassName extends ParentClass implements \ArrayAccess, \Countable {
    // constants, properties, methods
}

Lists of implements MAY be split across multiple lines, where each subsequent line is indented once. When doing so, the first item in the list MUST be on the next line, and there MUST be only one interface per line.

<?php

class ClassName extends ParentClass implements
    \ArrayAccess,
    \Countable,
    \Serializable
{
    // constants, properties, methods
}

4.3. Properties

Visibility MUST be declared on all properties.

The var keyword MUST NOT be used to declare a property.

There MUST NOT be more than one property declared per statement.

Property names SHOULD NOT be prefixed with a single underscore to indicate protected or private visibility.

A property declaration looks like the following.

<?php

class ClassName {
    public $foo = null;
}

4.4. Methods

Method names MUST be declared in camelCase().

Visibility MUST be declared on all methods.

Method names SHOULD NOT be prefixed with a single underscore to indicate protected or private visibility.

Method names MUST NOT be declared with a space after the method name. The opening brace MUST go on the same line as the method name, and the closing brace MUST go on the next line following the body. There MUST NOT be a space after the opening parenthesis, and there MUST NOT be a space before the closing parenthesis.

A method declaration looks like the following. Note the placement of parentheses, commas, spaces, and braces:

<?php

class ClassName {
    public function fooBarBaz($arg1, &$arg2, $arg3 = []) {
        // method body
    }
}

The major exception to this rule is Event Methods. Any method that has the following patterns:

'_handler',
'_create',
'_before',
'_override',
'_after',
'controller_'

Event methods MUST be camelCase separated by _.

4.5. Method Arguments

In the argument list, there MUST NOT be a space before each comma, and there MUST be one space after each comma.

Method arguments with default values MUST go at the end of the argument list.

<?php

class ClassName {
    public function foo($arg1, &$arg2, $arg3 = []) {
        // method body
    }
}

Argument lists MAY be split across multiple lines, where each subsequent line is indented once. When doing so, the first item in the list MUST be on the next line, and there MUST be only one argument per line.

When the argument list is split across multiple lines, the closing parenthesis and opening brace MUST be placed together on their own line with one space between them.

<?php

class ClassName {
    public function aVeryLongMethodName(
        ClassTypeHint $arg1,
        &$arg2,
        array $arg3 = []
    ) {
        // method body
    }
}

4.6. Global Functions

Global function names SHOULD be declared in camelCase().

Global function names that match php style; such as array_something() are allowed and MUST be declared in lowercase.

4.7. abstract, final, and static

When present, the abstract and final declarations MUST precede the visibility declaration.

When present, the static declaration MUST come after the visibility declaration.

<?php

abstract class ClassName {
    protected static $foo;

    abstract protected function zim();

    final public static function bar() {
        // method body
    }
}

4.8. Method and Function Calls

When making a method or function call, there MUST NOT be a space between the method or function name and the opening parenthesis, there MUST NOT be a space after the opening parenthesis, and there MUST NOT be a space before the closing parenthesis. In the argument list, there MUST NOT be a space before each comma, and there MUST be one space after each comma.

<?php
bar();
$foo->bar($arg1);
Foo::bar($arg2, $arg3);

Argument lists MAY be split across multiple lines, where each subsequent line is indented once. When doing so, the first item in the list MUST be on the next line, and there MUST be only one argument per line.

<?php
$foo->bar(
    $longArgument,
    $longerArgument,
    $muchLongerArgument
);

5. Control Structures

The general style rules for control structures are as follows:

  • There MUST be one space after the control structure keyword
  • There MUST NOT be a space after the opening parenthesis
  • There MUST NOT be a space before the closing parenthesis
  • There MUST be one space between the closing parenthesis and the opening brace
  • The structure body MUST be indented once
  • The closing brace MUST be on the next line after the body

The body of each structure MUST be enclosed by braces. This standardizes how the structures look, and reduces the likelihood of introducing errors as new lines get added to the body.

5.1. if, elseif, else

An if structure looks like the following. Note the placement of parentheses, spaces, and braces; and that else and elseif are on the same line as the closing brace from the earlier body.

<?php
if ($expr1) {
    // if body
} elseif ($expr2) {
    // elseif body
} else {
    // else body;
}

The keyword elseif SHOULD be used instead of else if so that all control keywords look like single words.

5.2. switch, case

A switch structure looks like the following. Note the placement of parentheses, spaces, and braces. The case statement MUST be indented once from switch, and the break keyword (or other terminating keyword) MUST be indented at the same level as the case body. There MUST be a comment such as // no break when fall-through is intentional in a non-empty case body.

<?php
switch ($expr) {
    case 0:
        echo 'First case, with a break';
        break;
    case 1:
        echo 'Second case, which falls through';
        // no break
    case 2:
    case 3:
    case 4:
        echo 'Third case, return instead of break';
        return;
    default:
        echo 'Default case';
        break;
}

5.3. while, do while

A while statement looks like the following. Note the placement of parentheses, spaces, and braces.

<?php
while ($expr) {
    // structure body
}

Similarly, a do while statement looks like the following. Note the placement of parentheses, spaces, and braces.

<?php
do {
    // structure body;
} while ($expr);

5.4. for

A for statement looks like the following. Note the placement of parentheses, spaces, and braces.

<?php
for ($i = 0; $i < 10; $i++) {
    // for body
}

5.5. foreach

A foreach statement looks like the following. Note the placement of parentheses, spaces, and braces.

<?php
foreach ($iterable as $key => $value) {
    // foreach body
}

5.6. try, catch

A try catch block looks like the following. Note the placement of parentheses, spaces, and braces.

<?php
try {
    // try body
} catch (FirstExceptionType $e) {
    // catch body
} catch (OtherExceptionType $e) {
    // catch body
}

6. Closures

Closures MUST be declared with a space after the function keyword, and a space before and after the use keyword.

The opening brace MUST go on the same line, and the closing brace MUST go on the next line following the body.

There MUST NOT be a space after the opening parenthesis of the argument list or variable list, and there MUST NOT be a space before the closing parenthesis of the argument list or variable list.

In the argument list and variable list, there MUST NOT be a space before each comma, and there MUST be one space after each comma.

Closure arguments with default values MUST go at the end of the argument list.

A closure declaration looks like the following. Note the placement of parentheses, commas, spaces, and braces:

<?php
$closureWithArgs = function ($arg1, $arg2) {
    // body
};

$closureWithArgsAndVars = function ($arg1, $arg2) use ($var1, $var2) {
    // body
};

Argument lists and variable lists MAY be split across multiple lines, where each subsequent line is indented once. When doing so, the first item in the list MUST be on the next line, and there MUST be only one argument or variable per line.

When the ending list (whether or arguments or variables) is split across multiple lines, the closing parenthesis and opening brace MUST be placed together on their own line with one space between them.

The following are examples of closures with and without argument lists and variable lists split across multiple lines.

<?php
$longArgs_noVars = function (
    $longArgument,
    $longerArgument,
    $muchLongerArgument
) {
   // body
};

$noArgs_longVars = function () use (
    $longVar1,
    $longerVar2,
    $muchLongerVar3
) {
   // body
};

$longArgs_longVars = function (
    $longArgument,
    $longerArgument,
    $muchLongerArgument
) use (
    $longVar1,
    $longerVar2,
    $muchLongerVar3
) {
   // body
};

$longArgs_shortVars = function (
    $longArgument,
    $longerArgument,
    $muchLongerArgument
) use ($var1) {
   // body
};

$shortArgs_longVars = function ($arg) use (
    $longVar1,
    $longerVar2,
    $muchLongerVar3
) {
   // body
};

Note that the formatting rules also apply when the closure is used directly in a function or method call as an argument.

<?php
$foo->bar(
    $arg1,
    function ($arg2) use ($var1) {
        // body
    },
    $arg3
);

7. Doc Blocks

  • Descriptions MUST BE a full sentence with a capital to start and period to end

  • Short, return and parameter descriptions MUST be included if present

  • There MUST be one space before and after parameters

/**
 * Short description.
 *
 * @param string $string Parameter descriptions must be a sentence with full stop.
 *
 * @return bool True if user is added else false.
 */

8. Conclusion

There are many elements of style and practice intentionally omitted by this guide. These include but are not limited to:

  • Declaration of global variables and global constants

  • Operators and assignment

  • Inter-line alignment

  • Class name prefixes and suffixes

  • Best practices

Future recommendations MAY revise and extend this guide to address those or other elements of style and practice.

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