How to correctly include templates? - symfony

Question

I am getting the following error when adding the template Variable "addPostForm" does not exist.
I want to include in my main template another template with a form that will be shown in a modal window
This is my controller
#[Route('/post/{id}/add', name: 'add_post')]
public function addPost(Request $request, EntityManagerInterface $entityManager) : Response
{
$post = new Post();
$form = $this->createForm(PostFormType::class, $post);
$form->handleRequest($request);
if ($form->isSubmitted() && $form->isValid()) {
$message = $form->get('message')->getData();
$post->setMessage($message);
$post->setAuthor($this->getUser());
$entityManager->persist($post);
$entityManager->flush();
return $this->redirectToRoute('app_home', ['id' => $this->getUser()->getId()]);
}
return $this->renderForm('post/post.html.twig', [
'addPostForm' => $form,
]);
}
And the template which is located at templates/post/post.html.twig
{{ form_start(addPostForm) }}
{{ form_row(addPostForm.message) }}
<button type="submit" class="btn btn-dark btn-sm">Register</button>
{{ form_end(addPostForm) }}
You need to connect to the template, which is here templates/home/index.html.twig
I used the include command for this {% include 'post/post.html.twig' %}, but it gives an error that the variable is not found

Answer 1

Thanks #DarkBee
I'm create form in my index controller
class HomeController extends AbstractController
{
#[Route('/home/{id}', name: 'app_home')]
public function index(User $user, Request $request, EntityManagerInterface $entityManager): Response
{
$post = new Post();
$form = $this->createForm(AddPostFormType::class, $post);
$form->handleRequest($request);
if ($form->isSubmitted() && $form->isValid()) {
$message = $form->get('message')->getData();
$post->setMessage($message);
$post->setAuthor($this->getUser());
$entityManager->persist($post);
$entityManager->flush();
return $this->redirectToRoute('app_home', ['id' => $this->getUser()->getId()]);
}
return $this->render('home/index.html.twig', [
'addPostForm' => $form->createView(),
'user' => $this->getUser(),
]);
}
}