Prevent second invoice creation when order is fully invoiced

[dudzio12]

I have an issue with two invoices inside one order.
The first one created is correct - it invoiced two items and shipping amount.
The second one invoiced same two items, but without shipping amount.

In the result of this, total_due in order is the amount of shipping amount. (total_paid does not include shipping amount).

The second invoice was created 1 minute after first one.

In the first try of PayU request, Magento returned error 500 with deadlock found in Magento DB, but the invoice was created correctly.

The second try was fully successfull, but it duplicated the invoice as described above.

To fix this issue, you should add canInvoice method to prevent duplicate invoice creation and if the invoice is already created - use that one to finish request. Magento should also prevent from invoicing same items.

I'm working on this now.

[agnnow1]

How is the work progressing on this? We have a problem on the store where Magento sometimes issues two invoices in the manner described above.