Object Calisthenics rules for PHP_CodeSniffer
DEPRECATED: PHP_CodeSniffer is great for handling spaces and char positions. Yet these rules are about code architecture and structure. In 2020, there is tool that suits this perfectly - PHPStan.
Saying that, object calisthenics were implemented as PHPStan rules in a symplify/phpstan-rules package. Use it instead 👇
includes:
- vendor/symplify/phpstan-rules/packages/object-calisthenics/config/object-calisthenics-rules.neon
- vendor/symplify/phpstan-rules/packages/object-calisthenics/config/object-calisthenics-services.neon
Object Calisthenics are set of rules in object-oriented code, that focuses of maintainability, readability, testability and comprehensibility. We're pragmatic first - they are easy to use all together or one by one.
Read post by William Durand or check presentation by Guilherme Blanco.
composer require object-calisthenics/phpcs-calisthenics-rules --devIf you know what you want, jump right to the specific rule:
- 1. Only X Level of Indentation per Method
- 2. Do Not Use "else" Keyword
- 5. Use Only One Object Operator (->) per Statement
- 6. Do not Abbreviate
- 7. Keep Your Classes Small
- 9. Do not Use Getters and Setters
vendor/bin/phpcs src tests -sp \
--standard=vendor/object-calisthenics/phpcs-calisthenics-rules/src/ObjectCalisthenics/ruleset.xml \
--sniffs=ObjectCalisthenics.Classes.ForbiddenPublicProperty# ecs.yaml
services:
ObjectCalisthenics\Sniffs\Classes\ForbiddenPublicPropertySniff: ~then
vendor/bin/ecs check src❌
foreach ($sniffGroups as $sniffGroup) {
foreach ($sniffGroup as $sniffKey => $sniffClass) {
if (! $sniffClass instanceof Sniff) {
throw new InvalidClassTypeException;
}
}
}👍
foreach ($sniffGroups as $sniffGroup) {
$this->ensureIsAllInstanceOf($sniffGroup, Sniff::class);
}
// ...
private function ensureIsAllInstanceOf(array $objects, string $type)
{
// ...
}In PHP_CodeSniffer:
vendor/bin/phpcs ... --sniffs=ObjectCalisthenics.Metrics.MaxNestingLevelIn ECS:
# ecs.yaml
services:
ObjectCalisthenics\Sniffs\Metrics\MaxNestingLevelSniff: ~In PHP_CodeSniffer:
<?xml version="1.0"?>
<ruleset name="my-project">
<rule ref="ObjectCalisthenics.Metrics.MaxNestingLevel">
<properties>
<property name="maxNestingLevel" value="2"/>
</properties>
</rule>
</ruleset>In ECS:
services:
ObjectCalisthenics\Sniffs\Metrics\MaxNestingLevelSniff:
maxNestingLevel: 2❌
if ($status === self::DONE) {
$this->finish();
} else {
$this->advance();
}👍
if ($status === self::DONE) {
$this->finish();
return;
}
$this->advance();In PHP_CodeSniffer:
vendor/bin/phpcs ... --sniffs=ObjectCalisthenics.ControlStructures.NoElseIn ECS:
# ecs.yaml
services:
ObjectCalisthenics\Sniffs\ControlStructures\NoElseSniff: ~❌
$this->container->getBuilder()->addDefinition(SniffRunner::class);👍
$containerBuilder = $this->getContainerBuilder();
$containerBuilder->addDefinition(SniffRunner::class);In PHP_CodeSniffer:
vendor/bin/phpcs ... --sniffs=ObjectCalisthenics.CodeAnalysis.OneObjectOperatorPerLineIn ECS:
# ecs.yaml
services:
ObjectCalisthenics\Sniffs\CodeAnalysis\OneObjectOperatorPerLineSniff: ~In PHP_CodeSniffer:
<?xml version="1.0"?>
<ruleset name="my-project">
<rule ref="ObjectCalisthenics.CodeAnalysis.OneObjectOperatorPerLine">
<properties>
<property name="variablesHoldingAFluentInterface" type="array" value="$queryBuilder,$containerBuilder"/>
<property name="methodsStartingAFluentInterface" type="array" value="createQueryBuilder"/>
<property name="methodsEndingAFluentInterface" type="array" value="execute,getQuery"/>
</properties>
</rule>
</ruleset>In ECS:
services:
ObjectCalisthenics\Sniffs\CodeAnalysis\OneObjectOperatorPerLineSniff:
variablesHoldingAFluentInterface: ["$queryBuilder", "$containerBuilder"]
methodsStartingAFluentInterface: ["createQueryBuilder"]
methodsEndingAFluentInterface: ["execute", "getQuery"]This is related to class, trait, interface, constant, function and variable names.
❌
class EM
{
// ...
}👍
class EntityMailer
{
// ...
}In PHP_CodeSniffer:
vendor/bin/phpcs ... --sniffs=ObjectCalisthenics.NamingConventions.ElementNameMinimalLengthIn ECS:
# ecs.yaml
services:
ObjectCalisthenics\Sniffs\NamingConventions\ElementNameMinimalLengthSniff: ~In PHP_CodeSniffer:
<?xml version="1.0"?>
<ruleset name="my-project">
<rule ref="ObjectCalisthenics.NamingConventions.ElementNameMinimalLength">
<properties>
<property name="minLength" value="3"/>
<property name="allowedShortNames" type="array" value="i,id,to,up"/>
</properties>
</rule>
</ruleset>In ECS:
# ecs.yaml
services:
ObjectCalisthenics\Sniffs\NamingConventions\ElementNameMinimalLengthSniff:
minLength: 3
allowedShortNames: ["i", "id", "to", "up"]❌
class SimpleStartupController
{
// 300 lines of code
}👍
class SimpleStartupController
{
// 50 lines of code
}❌
class SomeClass
{
public function simpleLogic()
{
// 30 lines of code
}
}👍
class SomeClass
{
public function simpleLogic()
{
// 10 lines of code
}
}❌
class SomeClass
{
// 20 properties
}👍
class SomeClass
{
// 5 properties
}❌
class SomeClass
{
// 20 methods
}👍
class SomeClass
{
// 5 methods
}In PHP_CodeSniffer:
vendor/bin/phpcs ... --sniffs=ObjectCalisthenics.Files.ClassTraitAndInterfaceLength,ObjectCalisthenics.Files.FunctionLength,ObjectCalisthenics.Metrics.MethodPerClassLimit,ObjectCalisthenics.Metrics.PropertyPerClassLimitIn ECS:
# ecs.yaml
services:
ObjectCalisthenics\Sniffs\Files\ClassTraitAndInterfaceLengthSniff: ~
ObjectCalisthenics\Sniffs\Files\FunctionLengthSniff: ~
ObjectCalisthenics\Sniffs\Metrics\MethodPerClassLimitSniff: ~
ObjectCalisthenics\Sniffs\Metrics\PropertyPerClassLimitSniff: ~In PHP_CodeSniffer:
<?xml version="1.0"?>
<ruleset name="my-project">
<rule ref="ObjectCalisthenics.Files.ClassTraitAndInterfaceLength">
<properties>
<property name="maxLength" value="200"/>
</properties>
</rule>
<rule ref="ObjectCalisthenics.Files.FunctionLength">
<properties>
<property name="maxLength" value="20"/>
</properties>
</rule>
<rule ref="ObjectCalisthenics.Metrics.PropertyPerClassLimit">
<properties>
<property name="maxCount" value="10"/>
</properties>
</rule>
<rule ref="ObjectCalisthenics.Metrics.MethodPerClassLimit">
<properties>
<property name="maxCount" value="10"/>
</properties>
</rule>
</ruleset>In ECS:
# ecs.yaml
services:
ObjectCalisthenics\Sniffs\Files\ClassTraitAndInterfaceLengthSniff:
maxLength: 200
ObjectCalisthenics\Sniffs\Files\FunctionLengthSniff:
maxLength: 20
ObjectCalisthenics\Sniffs\Metrics\PropertyPerClassLimitSniff:
maxCount: 10
ObjectCalisthenics\Sniffs\Metrics\MethodPerClassLimitSniff:
maxCount: 10This rules is partially related to Domain Driven Design.
- Classes should not contain public properties.
- Method should represent behavior, not set values.
❌
class ImmutableBankAccount
{
public $currency = 'USD'; private $amount;
public function setAmount(int $amount)
{
$this->amount = $amount;
}
}👍
class ImmutableBankAccount
{
private $currency = 'USD'; private $amount;
public function withdrawAmount(int $withdrawnAmount)
{
$this->amount -= $withdrawnAmount;
}
}In PHP_CodeSniffer:
vendor/bin/phpcs ... --sniffs=ObjectCalisthenics.Classes.ForbiddenPublicProperty,ObjectCalisthenics.NamingConventions.NoSetterIn ECS:
# ecs.yaml
services:
ObjectCalisthenics\Sniffs\Classes\ForbiddenPublicPropertySniff: ~
ObjectCalisthenics\Sniffs\NamingConventions\NoSetterSniff: ~In PHP_CodeSniffer:
<?xml version="1.0"?>
<ruleset name="my-project">
<rule ref="ObjectCalisthenics.NamingConventions.NoSetter">
<properties>
<property name="allowedClasses" type="array" value="*\DataObject"/>
</properties>
</rule>
</ruleset>In ECS:
# ecs.yaml
services:
ObjectCalisthenics\Sniffs\NamingConventions\NoSetterSniff:
allowedClasses:
- '*\DataObject'While using in practice, we found these rule to be too strict, vague or even annoying, rather than helping to write cleaner and more pragmatic code. They're also closely related with Domain Driven Design.
3. Wrap Primitive Types and Strings - Since PHP 7, you can use define(strict_types=1) and scalar type hints. For other cases, e.g. email, you can deal with that in your Domain via Value Objects.
4. Use First Class Collections - This rule makes sense, yet is too strict to be useful in practice. Even our code didn't pass it at all.
8. Do Not Use Classes With More Than Two Instance Variables - This depends on individual domain of each project. It doesn't make sense to make a rule for that.
-
1 feature per PR
-
every new feature must be covered by tests
-
all tests and style checks must pass
composer complete-check
We will be happy to merge your feature then.
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