nette/plugins/nette-dev/skills/php-coding-standards

PHP Coding Standards

Using nette/coding-standard

Install globally using /php-fixer:install-php-fixer. After installation, PHP files are automatically fixed when edited - see the php-auto-fixer skill for editing workflow rules (especially use statement ordering).

General Rules

• Every PHP file must include declare(strict_types=1)
• Use two empty lines between methods - Nette convention for visual separation in longer classes
• Document shut-up operator use: @mkdir($dir); // @ - directory may already exist
• Document weak comparison operators: // == accept null
• Multiple exceptions can be written in a single exceptions.php file, and multiple enums into enums.php
• Interface methods don't need visibility as they're always public
• All properties, return values, and parameters must have types
• Final constants don't need types as they're self-evident
• Write all code, comments, and variables in English only (even if communicating with the user in Czech)

Strings

• Use single quotes - they signal "no interpolation here," making code easier to scan
• Use double quotes only when the string contains apostrophes or interpolation is needed
• In HTML attributes, double quotes are standard

Naming Conventions

• Avoid abbreviations unless the full name is too long
• Use UPPERCASE for two-letter abbreviations (IO, DB), PascalCase/camelCase for longer ones (Http, Xml)
• Use nouns or noun phrases for class names
• Class names should include both specificity and generality (e.g., ArrayIterator)
• PascalCase for classes and class constants/enums
• camelCase for methods and properties
• Never use prefixes/suffixes like Abstract, Interface, or I - the type system already distinguishes them

Formatting

• Use TABs for indentation everywhere (PHP, JS, HTML, CSS/SCSS, NEON, Latte, ...)
• PHP follows Nette Coding Standard (based on PSR-12) with these modifications:
  • No space before parentheses in arrow functions: fn($a) => $b
  • No blank lines required between different use import types
  • When parameters span multiple lines, return type and opening brace go on separate lines:

// Short params - standard single-line
public function getItems(string $type): array
{
	// method body
}

// Multi-line params - return type and brace on separate lines
public function example(
	string $param,
	array $options,
): string
{
	// method body
}

Global Functions and Constants

• Write global functions/constants without leading backslash: count($arr) not \count($arr)
• For compiler-optimizable functions, add use function at the file beginning:

  use Nette;
  use function count, is_array, is_scalar, sprintf;
  

• Occasionally import constants that may help the compiler:

  use const PHP_OS_FAMILY;
  

Code Style Preferences

• Uses DOM API with HTML5 parser Lexbor for HTML processing
• Use try/catch for external operations (file I/O, network, database)
• Prefer modern PHP syntax and concise expressions:
  • Example: if (is_array($response['data'] ?? null)) instead of if (isset($response['data']) && is_array($response['data']))
• Use named arguments for boolean parameters whose meaning isn't obvious from context (e.g., is_a($obj, $class, allow_string: true)), but not when the method name makes it clear (e.g., setReadonly(true))
• Place interface/base class outside the namespace containing its implementations (e.g., Foo\Network next to Foo\Networks\*, not inside it) - this keeps the interface discoverable at the package level
• For structured data, prefer typed classes (DTOs) with public typed properties and default values over plain array. Arrays lose type information; typed objects let PHPStan catch errors at analysis time and give full IDE support.
• Don't add comments referencing specific bug fixes, issues, or tickets ("fixes #123", "workaround for bug X", "added in PR #456"). Only write comments with general validity that explain non-obvious logic any reader would benefit from. Git history provides the fix-specific context and doesn't rot over time.