PHP

Rules marked [enforced] are caught automatically by PHP Code Sniffer (ddev composer test) or PHPStan (ddev composer run-script phpstan).

Opening and closing tags [enforced]

Use <?php for logic and <?= for inline output. Never use the short tag <? or the ASP-style tag <%. Omit the closing ?> at the end of every file — a trailing newline after it can cause unexpected output.

// Good — class file, no closing tag
<?php

namespace App\Hook;

class ExampleHook
{
}

// Good — inline output with short-echo tag
<h1><?= esc_html($title) ?></h1>

// Bad — short tag
<? echo esc_html($title) ?>

// Bad — closing tag at end of file
<?php

class ExampleHook
{
}
?>

Indentation [enforced]

Use 4 spaces.

Array syntax

Use short array syntax [] instead of array().

// Good
$items = ['foo', 'bar'];

// Bad
$items = array('foo', 'bar');

String quotes

Use single quotes for plain strings. Use double quotes only when the string contains a variable or an escape sequence.

// Good
$greeting = 'Hello';
$message  = "Hello, {$name}";

// Bad
$greeting = "Hello";

Type declarations [enforced]

Always declare parameter types and return types. PHPStan will catch missing type declarations on new code.

// Good
public function getTitle(int $id): string
{
    return get_the_title($id);
}

// Bad
public function getTitle($id)
{
    return get_the_title($id);
}

Use ?Type for nullable values:

public function findPost(int $id): ?Timber\Post
{
    return Timber::get_post($id) ?: null;
}

Naming conventions

What	Convention	Example
Class	PascalCase	TeamMemberHook
Method	camelCase	getTeamMembers()
Variable	camelCase	$teamMembers
Constant	UPPER_SNAKE_CASE	PostTypeConstant::TEAM_MEMBER
File	Match class name	TeamMemberHook.php

Class structure

Order class members as follows: constants → properties → constructor → public methods → protected methods → private methods.

<?php

namespace App\Hook;

use App\Lib\Contracts\HookContract;

class TeamHook implements HookContract
{
    private const CACHE_KEY = 'team_members';

    private int $limit;

    public function __construct(int $limit = 10)
    {
        $this->limit = $limit;
    }

    public function register(): void
    {
        add_action('init', [$this, 'registerPostType']);
    }

    public function registerPostType(): void
    {
        // implementation
    }
}

PSR-2 [enforced]

The project follows PSR-2 for everything not covered above. PHP Code Sniffer enforces this automatically.

If you use VSCode, install the phpcs extension for inline feedback.

KISS

Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it.

Kernighan

If you need a comment to explain what a piece of code does, consider rewriting it instead.