Symfony version(s) affected: 4.2.2, 4.1.10, 3.4.21

Description

Since the last release the following error appears when submitting array data to the TextType:

[structure.stagedData] This value is not valid. ({"{{ value }}":"NULL"})

How to reproduce

$builder->add('structure', TextType::class, ['property_path' => 'structure.stagedData']);

Submit an array as data structure for the TextType.

e.g.:

[
    // ...
    'data' => [
        'some' => 'data',
        'more' => [
              'unstructured' => 'data',
        ],
    ],
]

This did work until the last release.

Possible Solution

Not sure is there another formType which can just be used for mapping the data instead of TextType?

Additional context

The following PR #29307 did add the breaking change.