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fix: ignore special transactions on block version 0 (pre DIP-0002) #675

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Merged
QuantumExplorer merged 2 commits into from
May 4, 2026
Merged

fix: ignore special transactions on block version 0 (pre DIP-0002) #675

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53e2917
update special_transaction_type decode in consensus_decode_from_finit…
owl352 Apr 19, 2026
bfd2d11
remove debug
owl352 Apr 21, 2026
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9 changes: 6 additions & 3 deletions dash/src/blockdata/transaction/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -597,10 +597,13 @@ impl Decodable for Transaction {
) -> Result<Self, encode::Error> {
let version = u16::consensus_decode_from_finite_reader(r)?;
let special_transaction_type_u16 = u16::consensus_decode(r)?;
let special_transaction_type = TransactionType::try_from(special_transaction_type_u16)
.map_err(|_| {
let special_transaction_type = if version != 0 {
TransactionType::try_from(special_transaction_type_u16).map_err(|_| {
encode::Error::UnknownSpecialTransactionType(special_transaction_type_u16)
})?;
})?
} else {
TransactionType::Classic
};
Comment on lines +600 to +606

@coderabbitai coderabbitai Bot May 4, 2026

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⚠️ Potential issue | 🟠 Major | 🏗️ Heavy lift

Preserve the raw type bits for version-0 transactions.

Line 600 fixes deserialization, but it also drops the original on-wire special_transaction_type_u16 when version == 0. After that, consensus_encode() and txid() re-emit/hash self.tx_type() as 0, so this malformed mainnet transaction no longer round-trips and its IDs can change after decode. If we need to treat pre-DIP-0002 transactions as Classic, we still need to retain the raw u16 (or full raw version word) somewhere so serialization and hashing stay faithful to the chain data.

🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@dash/src/blockdata/transaction/mod.rs` around lines 600 - 606, The fix must
preserve the original on-wire special_transaction_type_u16 for version == 0
while still treating it as TransactionType::Classic for logic; update the
struct/backing fields used by TransactionType::try_from so that the raw u16 (or
the full raw version word) is stored (e.g., add/keep a raw_special_tx_type
field) and use TransactionType::Classic only for behavior, but have
consensus_encode(), txid(), and tx_type() re-emit the preserved raw u16 when
serializing/hashing; change the deserialization branch around
TransactionType::try_from(special_transaction_type_u16) so version == 0 assigns
TransactionType::Classic but also saves special_transaction_type_u16 into the
raw field, and update consensus_encode()/txid()/tx_type() to prefer the raw
field for output.

let input = Vec::<TxIn>::consensus_decode_from_finite_reader(r)?;
// segwit
let mut segwit = input.is_empty();
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