[Form] String is the preferred value type for TextType

[peter-gribanov]

Reason symfony/symfony#41514 and symfony/symfony#41516

The text_empty_data_description.rst.inc file is a copy of empty_data_description.rst.inc:

This option determines what value the field will *return* when the submitted
value is empty (or missing). It does not set an initial value if none is
provided when the form is rendered in a view.

This means it helps you handling form submission with blank fields. For
example, if you want the ``name`` field to be explicitly set to ``John Doe``
when no value is selected, you can do it like this::

    $builder->add('name', null, [
        'required'   => false,
        'empty_data' => 'John Doe',
    ]);

This will still render an empty text box, but upon submission the ``John Doe``
value will be set. Use the ``data`` or ``placeholder`` options to show this
initial value in the rendered form.

If a form is compound, you can set ``empty_data`` as an array, object or
closure. See the :doc:`/form/use_empty_data` article for more details about
these options.

.. note::

    If you want to set the ``empty_data`` option for your entire form class,
    see the :doc:`/form/use_empty_data` article.
-
-.. caution::
-
-    :doc:`Form data transformers </form/data_transformers>` will still be
-    applied to the ``empty_data`` value. This means that an empty string will
-    be cast to ``null``. Use a custom data transformer if you explicitly want
-    to return the empty string.

[javiereguiluz]

@xabbuh do you have any comments about this proposal? Thanks!

[yceruto]

I wouldn't encourage the use of the inner data option for the default value. Cause that when it's a mapped field the data value set here will replace the bound value that comes from the underlying subject, thus it doesn't behave as a default value. There is already a warning note about it in
https://symfony.com/doc/current/reference/forms/types/text.html#data

We should use the underlying subject to the root form to set default values or a PRE_SET_DATA event listener instead.

[yceruto]

and the placeholder option is only for display but it also doesn't actually set an initial value for this field

[peter-gribanov]

This is a copy/paste of empty_data documentation
https://symfony.com/doc/current/reference/forms/types/text.html#empty-data
https://github.com/symfony/symfony-docs/blob/6.2/reference/forms/types/options/empty_data_description.rst.inc

[yceruto]

I see, maybe that's something to fix from 4.4 (in another PR).

[yceruto]

LGTM

[yceruto]

I see, maybe that's something to fix from 4.4 (in another PR).

[wouterj]

As far as I can see, this PR requires the 2 PRs submitted to the code repository to be merged first. I've added the "waiting code merge" label to clarify it.

If this is wrong, please let us know :)