This introduces Taproot wallet support. I fixed all the merge conflicts
and ensured that the tests pass, but this is still using the old sighash
(before Russell/Sanket/I redid it) so is not actually production ready.
Will be fixed when we bring Elements #1002 in.
Does the bare minimum to introduce Taproot wallet support with CT; just
adds a CPubKey blinding_pubkey to the taproot destination variant and
updates some visitors.
In future when we define blech32 we will need to make sure we are using
that encoding and using the pubkey.
e6cf0ed92d wallet, rpc: listdescriptors does not need unlocked (Andrew Chow)
3280704886 Pass in DescriptorCache to ToNormalizedString (Andrew Chow)
7a26ff10c2 Change DescriptorImpl::ToStringHelper to use an enum (Andrew Chow)
75530c93a8 Remove priv option for ToNormalizedString (Andrew Chow)
74fede3b8b wallet: Upgrade existing descriptor caches (Andrew Chow)
432ba9e543 wallet: Store last hardened xpub cache (Andrew Chow)
d87b544b83 descriptors: Cache last hardened xpub (Andrew Chow)
cacc391098 Move DescriptorCache writing to WalletBatch (Andrew Chow)
0b4c8ef75c Refactor Cache merging and writing (Andrew Chow)
976b53b085 Revert "Cache parent xpub inside of BIP32PubkeyProvider" (Andrew Chow)
Pull request description:
Currently fetching a normalized descriptor requires the wallet to be unlocked as it needs the private keys to derive the last hardened xpub. This is not very user friendly as normalized descriptors shouldn't require and don't involve the private keys except for derivation. We solve this problem by caching the last hardened xpub (which has to be derived at some point when generating the address pool).
However the last hardened xpub was not already being cached. We only cached the immediate parent xpub and derived child keys. For example, with a descriptor derivation path of `/84'/0'/0'/0/*`, the parent xpub that is cached is `m/84'/0'/0'/0`, and the child keys of `m/84'/0'/0'/0/i` (note that child keys would not be cached in this case). This parent xpub is not suitable for the normalized descriptor form as we want the key at `m/84'/0'/0'`. So this PR adds another field to `DescriptorCache` to cache the last hardened xpub so that we can use them for normalized descriptors.
Since `DescriptorCache` is changing, existing descriptor wallets need to be upgraded to use this new cache. The upgrade will occur in the background either at loading time (if the wallet is not encrypted) or at unlocking time in the same manner that `UpgradeKeyMetadata` operates. It will use a new wallet flag `WALLET_FLAG_LAST_HARDENED_XPUB_CACHED` to indicate whether the descriptor wallet has the last hardened xpub cache.
Lastly `listdescriptors` will not require the wallet to be locked and `getaddressinfo`'s `parent_desc` will always be output (assuming the upgrade has occurred).
ACKs for top commit:
fjahr:
tACK e6cf0ed92d
S3RK:
reACK e6cf0ed
jonatack:
Semi ACK e6cf0ed92d reviewed, debug-built and ran unit tests and some of the descriptor functional tests at each commit. I'm not very familiar with this code and it could be clearer to the uninitiated IMHO, so I'm not confident enough to give a full ACK. Various minor suggestions follow, most of them for readability, feel free to pick and choose.
meshcollider:
Code review + functional test run ACK e6cf0ed92d
Tree-SHA512: ac27aade8644525cd65bfcaf27ff32afb974085b1451faf4ff68c6671a690bd6a41d4f39a33cbf461ae0fbe85995c0a4c08dbd36171da1c1d2a1d00053ad298d
f9e37f33ce doc: IsFinalTx comment about nSequence & OP_CLTV (Yuval Kogman)
Pull request description:
It's somewhat surprising that a transaction's `nLockTime` field is ignored
when all `nSequence` fields are final, so this change aims to clarify this
behavior and cross reference relevant details of `OP_CHECKLOCKTIMEVERIFY`.
ACKs for top commit:
MarcoFalke:
ACK f9e37f33ce
Tree-SHA512: 88460dacbe4b8115fb1948715f09b21d4f34ba1da9e88d52f0b774a969f845e9eddc5940e7fee66eacdd3062dc40d6d44c3f282b0e5144411fd47eb2320b44f5
Instead of having a large blob of cache merging code in TopUp, refactor
this into DescriptorCache so that it can merge and provide a diff
(another DescriptorCache containing just the items that were added).
Then TopUp can just write everything that was in the diff.
754f134a50 wallet: Add error message to GetReservedDestination (Andrew Chow)
87a0e7a3b7 Disallow bech32m addresses for legacy wallet things (Andrew Chow)
6dbe4d1072 Use BECH32M for tr() desc, WitV1Taproot, and WitUnknown CTxDests (Andrew Chow)
699dfcd8ad Opportunistically use bech32m change addresses if available (Andrew Chow)
0262536c34 Add OutputType::BECH32M (Andrew Chow)
177c15d2f7 Limit LegacyScriptPubKeyMan address types (Andrew Chow)
Pull request description:
Currently bech32m addresses are classfied as bech32. Because bech32m is incompatible with bech32, we need to define a new `OutputType` for it so that it can be handled correctly. This PR adds `OutputType::BECH32M`, updates all of the relevant `OutputType` classifications, and handle requests for bech32m addresses. There is now a `bech32m` address type string that can be used.
* `tr()` descriptors now report their output type as `OutputType::BECH32M`. `WtinessV1Taproot` and `WitnessUnknown` are also classified as `OutputType::BECH32M`.
* Bech32m addresses are completely disabled for legacy wallets. They cannot be imported (explicitly disallowed in `importaddress` and `importmulti`), will not be created when getting all destinations for a pubkey, and will not be added with `addmultisigaddress`. Additional protections have been added to `LegacyScriptPubKeyMan` to disallow attempting to retrieve bech32m addresses.
* Since Taproot multisigs are not implemented yet, `createmultisig` will also disallow the bech32m address type.
* As Taproot is not yet active, `DescriptorScriptPubKeyMan` cannot and will not create a `tr()` descriptor. Protections have been added to make sure this cannot occur.
* The change address type detection algorithm has been updated to return `bech32m` when there is a segwit v1+ output script and the wallet has a bech32m `ScriptPubKeyMan`, falling back to bech32 if one is not available.
ACKs for top commit:
laanwj:
re-review ACK 754f134a50
Sjors:
re-utACK 754f134: only change is switching to `bech32m` in two `wallet_taproot.py` test cases.
fjahr:
re-ACK 754f134a50
jonatack:
ACK 754f134a50
Tree-SHA512: 6ea90867d3631d0d438e2b08ce6ed930f37d01323224661e8e38f183ea5ee2ab65b5891394a3612c7382a1aff907b457616c6725665a10c320174017b998ca9f
We don't want the legacy wallet to ever have bech32m addresses so don't
allow importing them. This includes addmultisigaddress as that is a
legacy wallet only RPC
Additionally, bech32m multisigs are not available yet, so disallow them
in createmultisig.
At verification time, the to be precomputed data can be inferred from
the transaction itself. For signing, the necessary witnesses don't
exist yet, so just permit precomputing everything in that case.
This provides a means to pass in a PrecomputedTransactionData object to
the MutableTransactionSignatureCreator, allowing the prevout data to be
passed into the signature hashers. It is also more efficient.
