Component view is using field clones not a reference.

[artur-stepien]

Steps to reproduce the issue

Create template overrides for com_contact.
Go to /templates/yourtheme/com_contact/contact/default_form.php
Try to update field attribute by putting after this:

<?php foreach ($fields as $field) : ?>

following code:

/* @var $field FormField */
$name = $field->getAttribute('name');
$this->form->setFieldAttribute($name, 'hint', $field->getAttribute('label'));

Now create new contact and create a new menu item for it.
Go to front end and look at the message form.

Expected result

Each text field should have a placeholder attribute same as field label (the code above just uses field label to set text field placeholder).

Actual result

Nothing changes.

System information (as much as possible)

Joomla 3.8.12

Additional comments

It looks like on the way to view form fields lose reference. That way it is impossible to update field attributes from inside the view. It leads to dirty workarounds like str_ireplace etc. It worked previously but I'm not sure in which version it started failing. There is still possibility to override form fields layouts for com_contact but that feels like overkill for simple attribute change.

[SharkyKZ]

I think your code is incorrect. You are modifying the form but the field is already assigned to a variable. So you either need to have two loops, one for modifying the form and one for rendering the fields, or use $this->form->renderField() instead of $field->renderField().

[ghost]

Comment above by @SharkyKZ isn't shown in issue Tracker.

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/22115.}

[joomla-cms-bot]

Set to "closed" on behalf of @Quy by The JTracker Application at issues.joomla.org/joomla-cms/22115

[artur-stepien]

@SharkyKZ I know how to make a workaround but its pointless. Objects should be returned as reference. Not a clone. 2 loops requirement is the result of issue, not a cure. Its no critical but its still a bug.

[ggppdk]

Ok 1 way of achieve setting the attribute (as mentioned by @SharkyKZ) are

$this->form->setFieldAttribute($field->fieldname, 'hint', $field->getAttribute('label'));
echo $this->form->renderField($field->fieldname, $field->group);

Another way (instead of str_replace) is to do

$field->__set('hint', $field->getAttribute('label'));
echo $field->renderField();

but why some place are using

$this->form->renderField('somefieldname');

and other are using
$field->renderField() ?

why not use everywhere ?

$this->form->renderField($field->fieldname, $field->group);