Merge bitcoin/bitcoin#33805: merkle: migrate path arg to reference and drop unused args

24ed820d4f merkle: remove unused `mutated` arg from `BlockWitnessMerkleRoot` (Lőrinc)
63d640fa6a merkle: remove unused `proot` and `pmutated` args from `MerkleComputation` (Lőrinc)
be270551df merkle: migrate `path` arg of `MerkleComputation` to a reference (Lőrinc)

Pull request description:

  ### Summary
  Simplifies merkle tree computation by removing dead code found through coverage analysis (following up on #33768 and #33786).

  ### History

  #### BlockWitnessMerkleRoot
  Original `MerkleComputation` was added in ee60e5625b (diff-706988c23877f8a557484053887f932b2cafb3b5998b50497ce7ff8118ac85a3R131) where it was called for either `&hash, mutated` or `position, &ret` args.
  In 1f0e7ca09c (diff-706988c23877f8a557484053887f932b2cafb3b5998b50497ce7ff8118ac85a3L135-L165) the first usage was inlined in `ComputeMerkleRoot`, leaving the `proot` and , `pmutated` values unused in `MerkleComputation`.
  Later in 4defdfab94 the method was moved to test and in 63d6ad7c89 (diff-706988c23877f8a557484053887f932b2cafb3b5998b50497ce7ff8118ac85a3R87-R95) was restored to the code, though with unused parameters again.

  #### BlockWitnessMerkleRoot
  `BlockWitnessMerkleRoot` was introduced in 8b49040854 where it was already called with `NULL` 8b49040854 (diff-34d21af3c614ea3cee120df276c9c4ae95053830d7f1d3deaf009a4625409ad2R3509) or an unused dummy 8b49040854 (diff-34d21af3c614ea3cee120df276c9c4ae95053830d7f1d3deaf009a4625409ad2R3598-R3599) for the `mutated` parameter.

  ### Fixes

  #### BlockWitnessMerkleRoot
  - Converts `path` parameter from pointer to reference (always non-null at call site)
  - Removes `proot` and `pmutated` parameters (always `nullptr` at call site)

  #### BlockWitnessMerkleRoot
  - Removes unused `mutated` output parameter (always passed as `nullptr`)

  The change is a refactor that shouldn't introduce *any* behavioral change, only remove dead code, leftovers from previous refactors.

  ### Coverage proof
  https://maflcko.github.io/b-c-cov/total.coverage/src/consensus/merkle.cpp.gcov.html

ACKs for top commit:
  optout21:
    utACK 24ed820d4f
  Sjors:
    utACK 24ed820d4f
  achow101:
    ACK 24ed820d4f
  sedited:
    ACK 24ed820d4f
  hodlinator:
    ACK 24ed820d4f

Tree-SHA512: 6960411304631bc381a3db7a682f6b6ba51bd58936ca85aa237c69a9109265b736b22ec4d891875bddfcbe8517bd3f014c44a4b387942eee4b01029c91ec93e1
This commit is contained in:
Ava Chow
2025-12-10 15:28:50 -08:00
4 changed files with 23 additions and 35 deletions

View File

@@ -3926,7 +3926,7 @@ static bool CheckWitnessMalleation(const CBlock& block, bool expect_witness_comm
// The malleation check is ignored; as the transaction tree itself
// already does not permit it, it is impossible to trigger in the
// witness tree.
uint256 hash_witness = BlockWitnessMerkleRoot(block, /*mutated=*/nullptr);
uint256 hash_witness = BlockWitnessMerkleRoot(block);
CHash256().Write(hash_witness).Write(witness_stack[0]).Finalize(hash_witness);
if (memcmp(hash_witness.begin(), &block.vtx[0]->vout[commitpos].scriptPubKey[6], 32)) {
@@ -4039,7 +4039,7 @@ std::vector<unsigned char> ChainstateManager::GenerateCoinbaseCommitment(CBlock&
int commitpos = GetWitnessCommitmentIndex(block);
std::vector<unsigned char> ret(32, 0x00);
if (commitpos == NO_WITNESS_COMMITMENT) {
uint256 witnessroot = BlockWitnessMerkleRoot(block, nullptr);
uint256 witnessroot = BlockWitnessMerkleRoot(block);
CHash256().Write(witnessroot).Write(ret).Finalize(witnessroot);
CTxOut out;
out.nValue = 0;