Cakephp 3 : Multiple Forms per page for the same model - cakephp

Question

I have a page where there are multiples forms generated with the FormHelper that aim at modifying the same entity. The problem is: validation errors will show up on both forms.
With cakephp 2, this problem was solved by extending Models (see : http://bakery.cakephp.org/articles/RabidFire/2010/06/26/multiple-forms-per-page-for-the-same-model ).
However I don't see how to do this with cakephp 3.
EDIT: i'm gonna describe more precisely what I'm trying to do.
I have two forms on the same page. The first one enables a user to change his email address, the other one to change his password.
Both forms are created with the Form helper and the same user entity.
In both forms, there is a field where the user should enter his current password (as a security measure). A validator will check if the password entered is correct before letting the email or the password to be changed.
Problem: let's say the user tries to change his email but typed a wrong password, the "wrong password" message will appear on both forms.

Answer 1

This is sort of an edge case that the FormHelper is not ready to handle graciously. But this is a solution, you will need 2 entities:
$user = $this->Users->get($id);
$user->unsetProperty('password');
$clonedUser = clone $user;
$this->set(compact('user', 'clonedUser'));
In your view, you build your forms in a way that you can detect which entity you should pass:
echo $this->Form->create($this->request->data('_form1') ? $user : $clonedUser);
... fields here
echo $this->Form->hidden('_form1', ['value' => 1]);
echo $this->Form->create($this->request->data('_form2') ? $user : $clonedUser);
... fields here
echo $this->Form->hidden('_form2', ['value' => 1]);
What the above code does is detecting which of the forms was previously submitted and render the form with either the empty cloned entity or the entity having the errors.

Answer 2

Stumbled upon this because I had the same requirement. I would go with José but move the logic to the Controller instead:
$callback = $this->Inquiries->newEntity();
$inquiry = $this->Inquiries->newEntity();
if ($this->request->is('post')) {
if ($this->request->data('_type') === 'callback') {
$callback = $this->Inquiries->patchEntity($callback, $this->request->data, ['validate' => 'callback']);
$entity = &$callback;
} elseif ($this->request->data('_type') === 'inquiry') {
$inquiry = $this->Inquiries->patchEntity($inquiry, $this->request->data);
$entity = &$inquiry;
}
if (!$entity->errors()) {
// do stuff here
}
}
$this->set(compact('callback', 'inquiry'));
Pass the type of the form:
echo $this->Form->input('_type', ['type' => 'hidden', 'value' => 'inquiry']);