Merge #13011: Cache witness hash in CTransaction

fac1223a568fa1ad6dd602350598eed278d115e8 Cache witness hash in CTransaction (MarcoFalke)
faab55fbb17f2ea5080bf02bc59eeef5ca746f07 Make CMutableTransaction constructor explicit (MarcoFalke)

Pull request description:

  This speeds up:
  * compactblocks (v2)
  * ATMP
  * validation and miner (via `BlockWitnessMerkleRoot`)
  * sigcache (see also unrelated #13204)
  * rpc and rest (nice, but irrelevant)

  This presumably slows down rescan, which uses a `CTransaction` and its `GetHash`, but never uses the `GetWitnessHash`. The slow down is proportional to the number of witness transactions in the rescan window. I.e. early in the chain there should be no measurable slow down. Later in the chain, there should be a slow down, but acceptable given the speedups in the modules mentioned above.

Tree-SHA512: 443e86acfcceb5af2163e68840c581d44159af3fd1fce266cab3504b29fcd74c50812b69a00d41582e7e1c5ea292f420ce5e892cdfab691da9c24ed1c44536c7

1 files changed, 1 insertions, 1 deletions

diff --git a/src/wallet/feebumper.cpp b/src/wallet/feebumper.cpp
index 7742d5cec4..0eb85a6e5c 100644
--- a/src/wallet/feebumper.cpp
+++ b/src/wallet/feebumper.cpp
@@ -185,7 +185,7 @@ Result CreateTransaction(const CWallet* wallet, const uint256& txid, const CCoin
     // If the output is not large enough to pay the fee, fail.
     CAmount nDelta = new_fee - old_fee;
     assert(nDelta > 0);
-    mtx =  *wtx.tx;
+    mtx = CMutableTransaction{*wtx.tx};
     CTxOut* poutput = &(mtx.vout[nOutput]);
     if (poutput->nValue < nDelta) {
         errors.push_back("Change output is too small to bump the fee");