Do you want more PHPStan violations?
Edit 2019–07–08: Good news! PHPStan 0.11.10 includes support for inferring private property type from constructor! https://github.com/phpstan/phpstan/releases/tag/0.11.10:
Turn on with inferPrivatePropertyTypeFromConstructor: true
We use PHPStan a lot and we love it. Some of us even donate each month some money via Patreon.
I faced an issue few months ago, and I hit the very same one today while I started a big refactoring of an application. And I totally forgot about it 😂 Memory sucks :)
So let’s talk about it, and see how to solve it. And now I hope I will remember to fix it on every project I’m working on.
Consider this piece of code:
class Model
{
}
class ServiceA
{
private $serviceB;
public function __construct(ServiceB $serviceB)
{
$this->serviceB = $serviceB;
}
public function init()
{
// This line will generate a FatalError (DateTime != Model)
$this->serviceB->process(new DateTime());
}
}
class ServiceB
{
public function process(Model $model)
{
}
}
I’m expecting to get this error:
Parameter #1 $model of method ServiceB::process() expects Model, DateTime given.
But why is it valid? Because PHPStan does not infer type from constructor argument. And this is totally valid to not do so.
A solution would be to add some PHPDoc:
class ServiceA
{
/** @var ServiceB */
private $serviceB;
}
In the Symfony community, we have some standards. Additionally, I hate useless PHPDoc. I don’t want to pollute my code by adding them everywhere.
Symfony’s coding standards state to not add the PHPDoc to a property if it can be inferred from the constructor, it is also the default configuration of PHP CS Fixer and it is considered a best practice by some.
Since PHPStan has a nice plugin system, I wrote a plugin to automatically add theses type-hint in PHPStan engine few months ago. I used it in my current application and I was able to find 45 new violations \o/
You can read the code and add it to your project if you want to.