I tried to stock shadow cloaks in my shop and it told me that i wouldnt want to sell second hand trash. Is this a bug or are they not supposed to be sold in shops?

If you check out the code:

Code:

if(obj->shopValue) {
	print(fd, "Why would you want to sell second hand trash?\n");
	return(0);
}

If the object's shopValue is already set, it means you can't sell it in your shop.

This essentialy means, since you bought the cloak from another shop, you're not allowed to restock it in yours.

Looks like the shopValue got saved to the database, meaning all new shadow cloaks loaded with a shop value. It's been cleared, so you can put any new ones in a shop.