[Validator] Inform developer if componant is missing

[Seb33300]

Symfony version(s) affected: 5.0.8

Description
I started a new Symfony 5 project and I wanted to enable the automatic validation feature in my validator config file:

framework:
    validation:
        # Enables validator auto-mapping support.
        # For instance, basic validation constraints will be inferred from Doctrine's metadata.
        auto_mapping:
            App\Entity\: []

But automatic validation was not working after that.
This was because as mentioned in the blog post, this feature require PropertyInfo component to work.

Maybe we should trigger an exception to informed the developer if this option is enabled but the component is not installed?

[xabbuh]

I don't think that would be correct either since mapping constraints based on Doctrine metadata would work as expected.

[Seb33300]

I am not sure to understand what you mean.

Automatic validation was not working as expected for me until I manually added the PropertyInfo component.

[xabbuh]

Can you debug what the DoctrineLoader does in your case? I don't see how it requires the PropertyInfo component to be present.

[Seb33300]

In the PR related to this feature: #27735

This feature automatically adds some validation constraints by inferring existing metadata. To do so, it uses the PropertyInfo component and Doctrine metadata

Maybe @dunglas can give more details?

[dunglas]

Actually you need PropertyInfo to extract some constraints from Doctrine metadata. But throwing an error if PropertyInfo isn’t installed is a bit harsh because you can also register your own guessers, without needing PropertyInfo.

[xabbuh]

There are two different loaders: The DoctrineLoader and the PropertyInfoLoader. The former one should work without the PropertyInfo component. That's why I was asking if you could please debug why it is not doing anything in your case.

[xabbuh]

I am going to close here for now due to the lack of feedback. Please let us know when you have more information and we can consider to reopen.