Why is the post ID 0?

Question

WordPress

I'm trying to display all products in a category

if ( have_posts() ) {
    while ( have_posts() ) {
        the_post();
        var_dump($post);
    }
}

I get this dump.

object(WP_Post)#13091 (24) {
  ["ID"]=>
  int(0)
  ["post_author"]=>
  string(1) "1"
  ["post_date"]=>
  string(19) "2018-04-17 08:53:16"
  ["post_date_gmt"]=>
  string(19) "2018-04-17 05:53:16"........

How can a post id even be 0?
In the admin panel, this post has a normal ID.
Therefore, then I can’t work with this post in any way and get a Woocommerce product from it.
And the most interesting thing is that I have almost the same cycle on the main page, only I get posts not from functions, but from custom fields, but the output is exactly the same post. But, on the main page it works, but here it doesn't.

Answer 1

I did not notice, it turns out that WC gave me not a post, but a category. Moreover, it looks like a post, and the WP_post class. I do not understand how the hierarchy in WC works.

Answer 2

Check if you have wp_reset_postdata() on the main page after the loop