Explore whether `PaidBolt12Invoice` should be moved to `PaymentMetadataStore`

[tnull]

In #733 we introduced a bolt12_invoice: Option<PaidBolt12Invoice> field to PaymentSuccessful.

While this works, it's a bit awkward to have a BOLT12-specific field on an event that is also used for other payment means. After #811 and #448 we should reconsider whether we should rather move storing the paid invoice to PaymentMetadata store, which might also allow to avoid the clone-on-persisting for the ffi version of the PaidBolt12Invoice.

[f3r10]

@tnull could I work on this issue?

After analyzing this issue, I consider that moving PaidBolt12Invoice into PaymentDetails (specifically into the Bolt12Offer / Bolt12Refund variants of PaymentKind has to be done.

• I think that PaidBolt12Invoice belongs with durable payment metadata, not a transient event.
• The PaidBolt12Invoice should be retrievable after the event is consumed
• get rid of this TODO, which exists because the invoice is embedded in a Clone-required Event variant; moving it to PaymentKind removes that constrain

 src/ffi/types.rs:857–862:
 impl Writeable for PaidBolt12Invoice {
 fn write<W: Writer>(&self, w: &mut W) -> Result<(), lightning::io::Error> {
 // TODO: Find way to avoid cloning invoice data.
 let ldk_type: LdkPaidBolt12Invoice = self.clone().into();
 ldk_type.write(w)
 }
 }

[tnull]

@tnull could I work on this issue?

After analyzing this issue, I consider that moving PaidBolt12Invoice into PaymentDetails (specifically into the Bolt12Offer / Bolt12Refund variants of PaymentKind has to be done.

• I think that PaidBolt12Invoice belongs with durable payment metadata, not a transient event.
• The PaidBolt12Invoice should be retrievable after the event is consumed
• get rid of this TODO, which exists because the invoice is embedded in a Clone-required Event variant; moving it to PaymentKind removes that constrain

src/ffi/types.rs:857–862:
impl Writeable for PaidBolt12Invoice {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), lightning::io::Error> {
// TODO: Find way to avoid cloning invoice data.
let ldk_type: LdkPaidBolt12Invoice = self.clone().into();
ldk_type.write(w)
}
}

No, as mentioned above, if we want to do this, it would be blocked on #811.

[f3r10]

No, as mentioned above, if we want to do this, it would be blocked on #811.

Got it. Would look into another issue. If you have any suggestion happy to work on it

[tnull]

This will slip to v0.9 due to #425 slipping.