Refund internals

Refunds travel in both directions. Store-side requests go through the ledger described in Concurrency and idempotency.

EDD → Paddle

• A checkbox Refund the payment in Paddle is added to EDD’s refund modal (edd_after_submit_refund_table), ticked by default.
• edd_refund_order (10, 3) runs only for admin form submissions ($_POST['data'], capability edit_shop_payments). It calls driver->refund( $order, $amount, $full, '', $refund ) with $full = $all_refunded && first refund.
• Billing: GET /adjustments?transaction_id=…&action=refund subtracts earlier pending or approved refunds per line. Then type full, or partial items[]: the refunded EDD items’ lines first (via _wpinterface_paddle_line_map and the refund record’s items), fees to the fee line, and the rest spread over lines that still have money left. EDD amounts are scaled by Paddle total ÷ EDD total, because Paddle may have added tax. Throws if more is asked than is left.
• Classic: payment/refund with the order’s Paddle order ID; partial amounts are scaled the same way.
• On success, an edd_order_transactions row is added to the refund record and a note to the order. On failure, a note explains how to finish the refund in Paddle.

Paddle → EDD

Orders::record_refund( $order, $amount, $full, $note, $targets = array() ) runs under the order lock with a fresh read:

• If the refund covers what is left, or is full: edd_refund_order( $id ).
• Otherwise partial_refund_lines() builds edd_refund_order( $id, $items, $adjustments ). Lines Paddle named come first ($targets: {type: item, cart_index, amount} or {type: fee, amount}, built by Billing_Driver::refund_targets() from _wpinterface_paddle_line_items and _wpinterface_paddle_line_map), then items, then fees. It respects each line’s get_refundable_amounts() and emits one entry per line.
• edd_is_order_refundable_by_override is forced to true for the call, because webhooks have no user and EDD’s refund window would otherwise refuse.
• Software Licensing revokes licenses when items become refunded (full refunds).