woothemes/woocommerce — pull request #5003 by splashingpixels (2014-03-01 04:44:51+00:00)
Title: wc_get_product_ids_on_sale should never return post id of 0 fixes #5002

on-sale ids included post id of zero which causes coupons to fail because post_parent could potentially be zero as in no parent which in turns invalidates the coupon on non-sale items.