Include outgoing payment description in audit memo

[mrfelton]

Include invoice memo in audit nodes for outgoing payments that pay to an invoice. This allows for more options to correlate money movements during reconciliation.

Context: Improves ability to reconcile payments related to peerswaps. See ElementsProject/peerswap#254 for additional context.

This pull request involves changes to the accounting package, specifically the entries.go, entries_test.go, filter.go, and filter_test.go files. The changes primarily involve the addition of a description field to the paymentInfo struct and the modification of the paymentNote function to include the memo field. The changes also involve modifications to the paymentEntry and paymentRequestDetails functions to accommodate the new description field.

Fix #181

Changes to entries.go and entries_test.go:

• func paymentReference(sequenceNumber uint64, preimage lntypes.Preimage) string {: Modified the paymentNote function to include a memo field and to append the memo and dest fields to a notes slice. The function now returns a string joined by the notes slice elements instead of just the dest string.
• func paymentEntry(payment paymentInfo, paidToSelf bool,: Modified the paymentNote function call in the paymentEntry function to include the payment.description field.
• func TestPaymentEntry(t *testing.T) {: Modified the paymentNote function call in the TestPaymentEntry test function to include the &invoiceMemo field. [1] [2]

Changes to filter.go and filter_test.go:

• type paymentInfo struct {: Added a description field to the paymentInfo struct.
• func preProcessPayments(payments []lndclient.Payment,: Modified the preProcessPayments function to include the description field in the paymentInfo struct.
• func paymentRequestDetails(paymentRequest string, decode decodePaymentRequest) (*route.Vertex, *string, error) {: Renamed the paymentRequestDestination function to paymentRequestDetails and modified it to return a description field in addition to the destination field.
• func TestPaymentRequestDestination(t *testing.T) {: Renamed the TestPaymentRequestDestination test function to TestPaymentRequestDetails and modified it to test the description field in addition to the destination field. [1] [2]

[guggero]

Thanks for the improvement!
One question about order of precedence.

[guggero]

I think this change alters the preference. Before, the data from paymentHtlcDestination took preference over paymentRequestDestination(). Now it's the other way around.

[mrfelton]

We need to inspect the payment request in order to get the description. So, given that we will always be inspecting the payment request if one exists, it seems that inspecting the HTLCs only makes sense as a fallback in case we weren't able to get the destination from the payment request.

Is there an expectation that the destination obtained from the HTLC's could be different from the destination in the payment request?

[guggero]

Actually, I'm not sure. That's why I'm not really comfortable changing the logic here. Would need to dig into the lnd code and docs to find out. But maybe @carlaKC has a quick answer for me?

[mrfelton]

I've pushed an additional commit which returns the original order of precedence for the destination

c478467

It does add some additional overhead though since in many cases we'd be inspecting HTLCs to find the destination even though we already know it from inspecting the payment request.

[bhandras]

Could you please squash the two commits?

[mrfelton]

done

[guggero]

thanks, LGTM 🎉

[bhandras]

LGTM, thanks @mrfelton 🎉

[bhandras]

Could you please squash the two commits?

[mrfelton]

Thanks for the reviews. Addressed the style nit and squashed all the commits.