So, like the title says, I am looking for a way to override the setting that makes a products that is out of stock not purchasable. I know I am supposed to use the "allow on backorder" setting to do this, but we have a big issue with this:
We need our product filter to be able to handle sorting on stock status based on the variations, and so far all the filters I have testet that is supposed to handle this will not work on stock status if it is on allow on backorder. There seems to be an issue with the amount of variations we have per product(80-200 variations per product), because if I create a test product with 2-10 variations, the filters I have tested seem to work just fine. And for some weird reason, the filter seems to work just fine if the variations use not in stock status instead of allow on backorder staus.
So, as a workaround, I am really hoping someone can help me to figure out how to allow purchase of out of stock products in the functions file :)