Wordpress custom user roles with upload_files true but edit_post false, how can i delete and edit media?

Based on @Marco answer I think I manage to write it simpler:

function allow_attachment_actions( $user_caps, $req_cap, $args ) {  // if no post is connected with capabilities check just return original array  if ( empty($args[2]) )    return $user_caps;  $post = get_post( $args[2] );  if ( 'attachment' == $post->post_type ) {    $user_caps[$req_cap[0]] = true;    return $user_caps;  }  // for any other post type return original capabilities  return $user_caps;}add_filter( 'user_has_cap', 'allow_attachment_actions', 10, 3 );

This way regardless of other permissions users can do everything with attachments.

One may define custom permissions for attachments actions and check if it exists along with post type check.

More info about hook used in this code https://codex.wordpress.org/Plugin_API/Filter_Reference/user_has_cap

after searching i found an answer to my question: to allow user without edit_post=true we can set it true only when the post_type is an attachment with the filter user_has_cap.For my purpose i write this hook

add_filter( 'user_has_cap', 'myUserHasCap', 10, 3 );function myUserHasCap( $user_caps, $req_cap, $args ) {$post = get_post( $args[2] );if ( 'attachment' != $post->post_type )    return $user_caps;if ( 'delete_post' == $args[0] ) {    if ( $user_caps['delete_others_posts'] )        return $user_caps;    if ( !isset( $user_caps['publish_recipes'] ) or !$user_caps['publish_recipes'] )        return $user_caps;    $user_caps[$req_cap[0]] = true;}if ( 'edit_post' == $args[0] ) {    if ( $user_caps['edit_others_posts'] )        return $user_caps;    if ( !isset( $user_caps['publish_recipes'] ) or !$user_caps['publish_recipes'] )        return $user_caps;    $user_caps[$req_cap[0]] = true;}return $user_caps;}

I hope can be usefull to other people that are searching an answer to my question.