Rendering cursor as collection in RoR give error `undefined method 'size' for #<PostgreSQLCursor::Cursor`

[ukolovda]

Rendering cursor as collection in RoR give error `undefined method 'size' for #from postgresql_cursor.

[ukolovda]

Errors arises in 2 places:

https://github.com/rails/rails/blob/db30dd6fe71341ac132bb1e850bd4df2596a2803/actionview/lib/action_view/renderer/collection_renderer.rb#L159

https://github.com/rails/rails/blob/db30dd6fe71341ac132bb1e850bd4df2596a2803/actionview/lib/action_view/renderer/collection_renderer.rb#L186

(Rails, last version 7.1.3.2).

It can be fixed appending to cursor singleton method size returning Float::NAN:

# app/controllers/books_controller.rb
  ...
  def index
    @books = Book.all.each_instance
    @books.define_singleton_method(:size) { Float::NAN }
  end

And removing #each_instance call in a app/views/books/index.html.erb.

Rendering works fine.

Additional effect:

• Logging row become:

Rendered collection of books/_book.html.erb [NaN times] (Duration: 24.5ms | Allocations: 11082)

• Method last? in partial rendering always false.