dee89438b8 Abstract out ComputeTapbranchHash (Russell O'Connor)
8e3fc99427 Do not use CScript for tapleaf scripts until the tapleaf version is known (Russell O'Connor)
Pull request description:
While BIP-341 calls the contents of tapleaf a "script", only in the case that the tapleaf version is `0xc0` is this script known to be a tapscript. Otherwise the tapleaf "script" is simply an uninterpreted string of bytes.
This PR corrects the issue where the type `CScript` is used prior to the tapleaf version being known to be a tapscript. This prevents `CScript` methods from erroneously being called on non-tapscript data.
A second commit abstracts out the TapBranch hash computation in the same manner that the TapLeaf computation is already abstracted. These two abstractions ensure that the TapLeaf and TapBranch tagged hashes are always constructed properly.
ACKs for top commit:
ajtowns:
ACK dee89438b8
instagibbs:
ACK dee89438b8
achow101:
ACK dee89438b8
sipa:
ACK dee89438b8
aureleoules:
reACK dee89438b8 - I verified that there is no behavior change.
Tree-SHA512: 4a1d37f3e9a1890e7f5eadcf65562688cc451389581fe6e2da0feb2368708edacdd95392578d8afff05270d88fc61dce732d83d1063d84d12cf47b5f4633ec7e