Container::getValues() when !isValid

[redeyecz]

Version: 3.1.1

Bug Description

When validation of form/container fails, any getValues() call after it (in onError / onValidate handlers) causes User warning

Steps To Reproduce

Presenter:

public function createComponentBug()
  {
      $form = new Form();
      $form->addText('test');
      $form->addSubmit('submit');

      $form->onValidate[] = [$this, 'onValidate'];
      $form->onValidate[] = [$this, 'onValidate2'];
      return $form;
  }

  public function onValidate(Form  $form) {
      dump('validation fail');
      $form->addError('Failed');
  }
  public function onValidate2(Form  $form) {
      dump('second validation');
      dump($form->isValid());
      dump($form->getValues());
  }

Latte:

{block content}
   {control bug}
{/block}

Outputs:

dump('validation fail') 📍'validation fail'
dump('second validation') 📍'second validation'
dump($form->isValid()) 📍false

... and triggers the warning

Expected Behavior

When validating, we usually append additional info from submitted values why the form was invalid, this makes it really awkward to use with custom validators (or when skipping netteForms.js validation for complex nested controls). I'd not expect it to throw any warnings when using getValues() with invalid form/container

Additionally, the same error occurs when the validator has second argument in it's signature!

Possible Solution

Just ... remove it? What's the point?

forms/src/Forms/Container.php

Lines 115 to 117 in 05d14fe

	if ($form && $form->isSubmitted() && !$form->isValid()) {
	trigger_error(__METHOD__ . '() invoked but the form is not valid.', E_USER_WARNING);
	}