`lightning-invoice` previously had a dependency on the entire
`lightning` crate just because it wants to use some of the useful
types from it. This is obviously backwards and leads to some
awkwardness like the BOLT 11 invoice signing API in the `lightning`
crate taking a `[u5]` rather than a `Bolt11Invoice`.
Here we finally rectify this issue, swapping the dependency order
and making `lightning` depend on `lightning-invoice` rather than
the other way around.
This moves various utilities which were in `lightning-invoice` but
relied on `lightning` payment types to make payments to where they
belong (the `lightning` crate), but doesn't bother with integrating
them well in their new home.
Use the `hex-conservative` crate directly from `bitcoin` instead of from
`hashes`. Although it makes no real difference it is slightly more clear
and more terse.
The `hex` crate is re-exported by `rust-bitcoin` so we can get it from
there instead of explicitly depending on it. Doing so reduces the
maintenance burden and helps reduce the likelyhood of getting two
versions in the dependency graph.
Since `lightning-invoice` now depends on the `bitcoin` crate
directly, also depending on the `bitcoin_hashes` crate is redundant
and just means we confuse users by setting the `std` flag only on
`bitcoin`. Thus, we drop the explicit dependency here and replace
it with `bitcoin::hashes`.
This adds support for setting the new payment metadata field in
BOLT11 invoices, using a new type flag on the builder to enforce
transition correctness.
We allow users to set the payment metadata as either optional or
required, defaulting to optional so that invoice parsing does not
fail if the sender does not support payment metadata fields.
This matches the spec and helps avoid any confusion around
naming. We're also then consistent with `cltv_expiry` in an HTLC being
the actual block height value for the CLTV and not a delta.
The BOLT 11 invalid invoice test vectors suggest failing to parse
invoices which have an amount which is not a whole number of
millisatoshis. lightning-invoice, however, happily parses such
invoices. While we could continue to parse them, failing them makes
for one less check on the user code side, so we might as well.
In order to keep the invoice creation less likely to fail, we also
switch the Builder amount-setting function to use millisatoshis.
This adds two additional tests from the BOLT 11 invalid invoice
tests, fixing the two errors that broke them. It fixes a panic on
the "nonrecoverable signature" test and makes the error variant
more sensible on the bogus SI prefix test.
Instead of relying on users to set an invoice's features correctly,
enforce the semantics inside InvoiceBuilder. For instance, if the user
sets a PaymentSecret then InvoiceBuilder should ensure the appropriate
feature bits are set. Thus, for this example, the TaggedField
abstraction can be retained while still ensuring BOLT 11 semantics at
the builder abstraction.
