Duplicate purchase events sent every time checkout completion page is refreshed

Problem/Motivation

Similar to 🐛 Commerce begin_checkout event can fire multiple times with ajax panes Needs review , this module resends the purchase event every time the checkout completion page is loaded. You should only ever send the purchase event once, and it should be based on order placement or checkout completion event as described in 📌 Send the purchase event when an order is placed, not paid Needs review .

Steps to reproduce

Checkout and keep on refreshin' that completion page.

Proposed resolution

The checkout flow form alter hook should stop injecting the purchase event at the very least, or else set a session variable or cookie to ensure the event is not outputted twice.

Remaining tasks

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