Symfony version(s) affected: 4.3.0, 4.3.1

Description

The auto-validation introduced in #27735 leads to an Assert\Length() validator to doctrine mapped fields with a length, but breaks for fields with length and type binary because of an invalid charset.

How to reproduce

• Create an entity with a field mapping including e.g.: @ORM\Column(type = "binary", length = 4). In the following, I call this field $hash.
• Set the value of this field to a raw one, e.g. in the constructor $this->hash = \hash('crc32', 'whateverYouWantToHash\n...\nTest', true);
• Create a form for this entity (no need for a field for the property $hash), you can have the form entirely for another field. Submit & validate the form. It will never be valid, as the Length validator will yield the invalid charset error for our $hash field.

Possible Solution

A workaround is to either:

• simply disable the autovalidation (for this field)
• overwrite the validation with an Assert\Length(groups={"notexisting"})

I feel like these are workarounds because I expect the validator to not only read and interpret part, but all of the doctrine annotation.

A possible solution would be to either:

• interpret the whole doctrine annotation
• make Assert\Length() charset independent (I do not know if and how this would be possible)
• validate only the submitted fields instead of the whole entity

Additional context