Unable to call modifying methods on types imported from other realms

[deelawn]

I'm not sure this is a problem but it could use further explanation. I was looking at an issue @leohhhn brought up regarding an error he was getting when trying to add a post to a blog. In summary, the issue was:

• A realm exists with an instance of the Blog type, defined in the blog package
• Calling a modifying method on the Blog instance results in the error cannot modify external-realm or non-realm object

I wrote a txtar script to exemplify the issue:

gnoland start

gnokey maketx addpkg -pkgdir $WORK/blogtest -pkgpath gno.land/r/blogtest -gas-fee 1000000ugnot -gas-wanted 2000000 -broadcast -chainid=tendermint_test test1
gnokey maketx addpkg -pkgdir $WORK/owner -pkgpath gno.land/r/owner -gas-fee 1000000ugnot -gas-wanted 2000000 -broadcast -chainid=tendermint_test test1

gnokey maketx call -pkgpath gno.land/r/owner -func AddPost -args 'my first post' -gas-fee 1000000ugnot -gas-wanted 2000000 -broadcast -chainid=tendermint_test test1

-- owner/blog.gno --
package owner

import blog "gno.land/r/blogtest"

var Blog = new(blog.Blog)

func AddPost(title string) {
    Blog.AddPost(title)
}

func GetPost() blog.Post {
    return Blog.Post
}

-- blogtest/blog.gno --
package blogtest

type Blog struct {
    Post  Post
}

type Post struct {
    Title string
}

func (b *Blog) AddPost(title string) {
    b.Post = Post{title}
}

In the case above the error will happen when calling AddPost from the owner realm. I'm not sure why this isn't allowed because the only object being modified is that which is owned by the owner realm, so it isn't as if this call is modifying another realm's state.

[deelawn]

This may be addressed by #1257. Will check to confirm