invalid alter statement with json data type using mariadb

[gaetan-petit]

Bug Report

Q	A
Version	3.7.2

Summary

When updating schema in our Symfony application with doctrine:schema:update --force --complete alter table statement is invalid for json columns.

Current behaviour

Generated alter look like so:
ALTER TABLE my_table CHANGE data data JSON CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '(DC2Type:json)';

Removing CHARACTER SET utf8mb4 gives a correct statement.

How to reproduce

Entity:

<?php

namespace App\Entity;

#[ORM\Entity()]
class MyEntity
{
    #[ORM\Column(type: 'json')]
    private ?array $data = [];
}

Expected behaviour

Correct alter statement.

[gaetan-petit]

I suspect that this comes from the dbal now supporting the native json format from mariadb instead of relying on longtext. I think this changes should be investigated: #5916