fix!: exact weight pricing for grouped legacy inputs in mixed txs - #63
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evanlinjin wants to merge 2 commits into
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fix!: exact weight pricing for grouped legacy inputs in mixed txs#63evanlinjin wants to merge 2 commits into
evanlinjin wants to merge 2 commits into
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…y_count Fixes CoinSelector::input_weight undercounting candidates that group multiple legacy inputs in a segwit transaction (where each legacy input serializes a 1 WU empty witness). Tracking segwit and legacy input counts separately also allows a single Candidate to mix legacy and segwit inputs.
…legacy Replaces the boolean is_segwit parameter in Candidate::new with explicit new_segwit and new_legacy constructors. Clarifies in doc comments that satisfaction_weight is the additional weight required beyond TXIN_BASE_WEIGHT (which already accounts for a 1-byte scriptSigLen).
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Fixes
CoinSelector::input_weightundercounting candidates that group multiple legacy inputs in a segwit transaction (where each legacy input serializes a 1 WU empty witness).Previously,
CoinSelectoradded 1 WU per non-segwit candidate if the transaction was segwit. This meant a candidate representing a group of N legacy inputs came out N-1 WU short.This PR:
Candidatefieldsinput_countandis_segwitwithsegwit_countandlegacy_count.Candidateto mix legacy and segwit inputs and still be priced exactly.Candidate::newwith explicitCandidate::new_segwitandCandidate::new_legacyconstructors to clarify thatsatisfaction_weightis the additional weight required beyondTXIN_BASE_WEIGHT(which already accounts for a 1-bytescriptSigLen).Note: This replaces #62 and #61. #61 introduced
empty_witness_refundwhich was problematic. #62 introduced an invariant (no mixing legacy and segwit inputs in a candidate) that is problematic for downstream crates.