Reset back to Bitcoin PSBT and disable PSBT/PSET handling in wallet and
rpc.
This is just a reset to allow for PSBTv2 change and then a new and
improved PSET.
Changes API for AcceptToMemoryPool to no longer check maximum fee; we remove
this check from interfaces::CChain::testPeginClaimAcceptance. This is fine,
the check never should have been there (this method's job is to notice double
claim attempts and provide a more helpful message to the user; other mempool
failures should be caught later in the `claimrawpegin` logic when we call
`pwallet->commitTransaction` which actually subits to the mempool). It was
only checking fees because the API made it easier to do so than to not.
Spent a while figuring out where this new function should live now that
the PSBT stuff has been pulled into src/psbt.cpp and the wallet, and isn't
mixed up with the RPC logic.
In the end I modified the the function to return a normal error rather
than throwing an RPC exception and put it in src/psbt.cpp with the other
functions that behave this way.
Added a method testPeginClaimAcceptance to interfaces::CChain. It is not clear
to me that this is meaningfully different from the existing method broadcastTransaction
(with the `relay` flag set to false so it doesn't actually broadcast), except
that this method returns the TxValidationState, which we display to the user
in the RPC error. Worth revisiting this.
Another nonobvious change was replacing a block of mempool-searching logic
in wallet/rpcwallet.cpp with the single line `pwallet->chain().findCoins(coins)`.
This I stole from the current state of upstream #17211, our favorite in-progress
PR from which the original logic came.
Also re-`static`'d a method in src/script/standard.cpp which we had made globally
visible for some historical reason, but which I noticed diffing that file against
upstream.
I really like this PR, but it wound up being pretty nontrivial to merge.
The crux is that it pulls PSBT signing logic into scriptpubkey manager,
which is where it belongs, but for us this means reasoning about pegins
inside script/sign.cpp.
However, sign.cpp is part of libbitcoin_common, which does not include
anything for reasoning about PoW or RPC (lol) or anything heavy about
that. This means that some pegin validation had to remain split between
the wallet/rpc layer and sign.cpp. I added a new file script/pegins.cpp
which has the (one) method we actually need in sign.cpp.
Aside from that, this diff is very large but is mostly just moving our
code changes to wallet/psbtwallet.* into wallet/wallet.* where those
functions now live. As far as review, it's probably not worthwhile to
spend too much too much time on this since it's going to be change
again in #16528 and others. The test coverage is pretty extensive.
