PSBT lacking Eq implementation

[dr-orlovsky]

PartiallySignedTransaction, psbt::Output and psbt::Input all lacking Eq implementation (but have PartialEq). Was this intentional?

If not, I see two ways forward with the implementation: adding derive or manual implementation doing BIP-174 serialization to a vector and byte-comparing those vectors.

[sanket1729]

If not, I see two ways forward with the implementation: adding derive or manual implementation doing BIP-174 serialization to a vector and byte-comparing those vectors.

Same Psbts can have different serializations because the order in which we serialize keys is not defined. Even though the serialization in rust-bitcoin is deterministic, other implementations need not follow the same. I think we have to derive it on the Psbt data structure.

[dr-orlovsky]

@sanket1729 derived in #932

[apoelstra]

I'm not sure how to interpret Sanket's comment, but we should implemnet Eq everywhere here. This looks like an oversight.

[sanket1729]

@apoelstra, I think we are on the same page. There were two ways to derive Eq.

• [#derive(Eq)]
• Compare the consensus encoding.

I suggested using [#derive(Eq)] because the same Psbt structures need to necessarily have the same consensus encoding(key-value pairs can be serialized in any order).

[dr-orlovsky]

@sanket1729 I think @apoelstra meant that we need to introduce support for hidden branches into PSBT.