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.
Moved GetOnlinePakKey to the scriptpubkey manager; the other blinding
stuff remains in the CWallet. At some point after the rebase we should
consider whether there's a better separation to be had between the PAK
related stuff now that we have wallet boxes.
This is the start of some nontrivial wallet refactoring by achow. See
https://github.com/bitcoin-core/bitcoin-devwiki/wiki/Wallet-Class-Structure-Changes
for a high-level design.
This PR moves some stuff out of CWallet into a dummy "box" LegacyScriptPubKeyMan
which is (currently) very tightly coulped to CWallet. Because of the coupling there
are currently null-checks that cannot fail, things which assume non-nullness which
will eventually be wrong, and a plethora of currently-equivalent ways to get from
a CWallet to a provider or back.
Our approach is basically to ignore the refactoring; leave the blinding key stuff
in CWallet and have it call into the wallet's provider when we are obtaining the
underlying keys.
Later, probably in a post-rebase PR, we should rethink how we manage blinding keys
to more closely match Core's "all keys go into providers" model.
I'm sorry, this should have been a few commits, but it got away from me
as the scope of this refactoring was not immediately obvious. It essentially
just moves code around so hopefully is not too hard to review. --asp
