Extension to infer type (generics params) of class

[MartinMystikJonas]

Would it be possible to somehow write extension that automatically infers type of class (generics parameters) from annotation or naming convention. Yet again this is motivated by need to improve type checks in large codebase (hundreds of classes) without need to manually write generics annotations for each of them.

Basically I want interpret:

/**
 * @mapperEntity User
 */
class UserMapper extends Mapper

as:

/**
 * @mapperEntity User
 * @extends Mapper<User, UserCollection>
 */
class UserMapper extends Mapper

Is it possible?

[ondrejmirtes]

Not directly, but it depends on what the first type variable of Mapper does in Mapper. If you simply have @return T somewhere in Mapper that maps to @return User in UserMapper, then you can write a dynamic return type extension for that.

Again, the best course of action is to generate the @extends. It's achievable with a simple search+replace.

[MartinMystikJonas]

Real world situation is bit more complicated for simple replace but I probably would go for Rector.

[genesiscz]

I actually wrote something like that few days ago. Maybe this helps a bit @MartinMystikJonas

	private const EXTENDS_CLASS = '#(Mapper)#';

	/**
	 * @return string[]
	 */
	public function getNodeTypes(): array
	{
		return [Class_::class];
	}

	/**
	 * @param Class_ $node
	 */
	public function refactor(Node $node): ?Node
	{
		if ($this->shouldSkip($node)) {
			return null;
		}

		/** @var PhpDocInfo|null $phpDocInfo */
		$phpDocInfo = $node->getAttribute(AttributeKey::PHP_DOC_INFO);
		if ($phpDocInfo === null) {
			return null;
		}

		$this->addExtendsNode(
			$phpDocInfo,
			$this->getModelName($this->getName($node), false)
		);

		return $node;
	}

	function addExtendsNode(PhpDocInfo $phpDocInfo, string $modelName): void {

		$tag = "extends";
		/** @var  PhpDocTagNode $child */
		foreach ($phpDocInfo->getPhpDocNode()->children as $index => $child) {
			if (isset($child->name) && $child->name === "@ignoreGenerator") {
				return;
			}

			if ($tag === "extends" && isset($child->name) && $child->name === "@extends") {
				assert($child->value instanceof AttributeAwareExtendsTagValueNode);
				$generics = $child->value->type->genericTypes;

				if (count($generics) > 0 && strpos($modelName, $generics[0]->name) !== false) {
					return;
				}
			}
		}

		$extendsTag = new ExtendsTagValueNode(
			new GenericTypeNode(
				new IdentifierTypeNode("Mapper"),
				[
					new IdentifierTypeNode($modelName)
				]
			), ""
		);
		$phpDocInfo->addPhpDocTagNode(
			new AttributeAwarePhpDocTagNode(
				"@$tag",
				$this->attributeAwareExtendsTagValueNodeFactory->create(
					$extendsTag, "@$tag"
				)
			)
		);
	}

	private function shouldSkip(Class_ $class): bool
	{
		if (!$class->extends) {
			return true;
		}

		if ($class->isAbstract()) {
			return true;
		}
		return !Strings::match($this->getName($class->extends), self::EXTENDS_CLASS);
	}