I am not able to reproduce this issue.

Created a custom text area field with maxlength value.
The markup has the maxlength attribute.

@Quy , according to the textarea field layout code this will only work if the $maxlength has the entire attribute instead of just an integer, for example, if the $maxlength = 'maxlength="1000"'

I just noticed there's no @var documentation, but IMHO it should work just like the other variables, which contain the value only instead of the attribute_name="attribute_value"

Your PR will break the custom textarea field. See markup.

<textarea name="jform[com_fields][text-area]" id="jform_com_fields_text_area"   class="form-control"           maxlength=" maxlength="1000""   ></textarea>

The character count requires two attributes in the xml

				maxlength="160"
				charcounter="true"

@machadoug You have the same issue with rows (4) and cols (20) attributes displaying only the values. It is not happening in core so it must be on your end. Please provide steps/code to reproduce.

@machadoug I suspect you use the textarea layout with your own field,
because for core textarea field the maxlength is set in the class:

It looks strange to me, but it works like that since ~3.7 version

I was indeed using a custom Textarea field in my extension. I was under the impression that we should use only the attribute value, not attribute="value". Like the onchange, onclick and autocomplete attributes.

Maybe we should include something in the code documentation explaining it's a string and not an integer?

 * @var   string   $rows         rows attribute for the field.
 * @var   string   $cols         cols attribute for the field.
 * @var   string   $maxlength    maxlength attribute for the field.

I was under the impression that we should use only the attribute value, not attribute="value". Like the onchange, onclick and autocomplete attributes.

That is correct expectation.
But I cannot say why it like that for textarea.

Would be good to fix it. Only need to care about backward compatibility here.
The fix should move this

And in layout doing something like:

$maxlengthAttr = '';

if ($maxlengt)
{
  $maxlengthAttr = is_numeric($maxlength) ? ' maxlength="' . $maxlength . '"' : $maxlength;
}

The same for rows and cols attribute.

@machadoug I have added that changes to your PR

It ready for testing:
Make sure textarea field still working as before.

This pull request has automatically rebased to 4.2-dev.

This pull requests has been automatically converted to the PSR-12 coding standard.

I have tested this item ✅ successfully on 7b37d37

This pull request has been automatically rebased to 4.4-dev.

This pull request has been automatically rebased to 5.2-dev.

I have tested this item ✅ successfully on 82dc13f