The fs.* files are already part of the libbitcoin_util library. With the
introduction of the fs_helpers.* it makes sense to move fs.* into the
util/ directory as well.
This is an extraction of filesystem related functions from util/system
into their own utility file.
The background of this commit is an ongoing effort to decouple the
libbitcoinkernel library from the ArgsManager defined in system.h.
Moving these functions out of system.h allows including them from a
separate source file without including the ArgsManager definitions from
system.h.
e43a547a36 refactor: wallet, do not translate init arguments names (furszy)
Pull request description:
Simple, and not interesting, refactor that someone has to do sooner or later. We are translating some init arguments names when those shouldn't be translated.
ACKs for top commit:
achow101:
ACK e43a547a36
MarcoFalke:
lgtm ACK e43a547a36
ryanofsky:
Code review ACK e43a547a36. Just rebased since last review.
Tree-SHA512: c6eca98fd66d54d5510de03ab4e63c00ba2838af4237d2bb135d01c47f8ad8ca9aa7ae1e45cf668afcfb9dd958b075a1756cc887b3beef2cb494933d4d83eab0
When producing a dummy signature for the purpose of estimating the transaction fee, do not assume an external signer performs R-value grinding on the signature.
In particular, this avoids a scenario where the fee rate is 1 sat / vbyte and a transaction with a 72 byte signature is not accepted into our mempool.
This commit also drops the nullptr default for CCoinControl arguments for functions that it touches. This is because having a boolean argument right next to an optional pointer is error prone.
Co-Authored-By: S3RK <1466284+S3RK@users.noreply.github.com>
9486509be6 wallet, rpc: Update migratewallet help text for encrypted wallets (Andrew Chow)
aaf02b5721 tests: Tests for migrating wallets by name, and providing passphrase (Andrew Chow)
7fd125b27d wallet: Be able to unlock the wallet for migration (Andrew Chow)
6bdbc5ff59 rpc: Allow users to specify wallet name for migratewallet (Andrew Chow)
dbfa345403 wallet: Allow MigrateLegacyToDescriptor to take a wallet name (Andrew Chow)
Pull request description:
`migratewallet` currently operates on wallets that are already loaded, however this is not necessarily required, and in the future, not possible once the legacy wallet is removed. So we need to also be able to give the wallet name to migrate.
Additionally, the passphrase is required when migrating a wallet. Since a wallet may not be loaded when we migrate, and as we currently unload wallets when migrating, we need the passphrase to be given to `migratewallet` in order to migrate encrypted wallets.
Fixes #27048
ACKs for top commit:
john-moffett:
reACK 9486509be6
pinheadmz:
ACK 9486509be6
furszy:
ACK 9486509b
Tree-SHA512: 35e2ba69a148e129a41e20d7fb99c4cab7947b1b7e7c362f4fd06ff8ac6e79e476e07207e063ba5b80e1a33e2343f4b4f1d72d7930ce80c34571c130d2f5cff4
6a5b348f2e test: test rescanning encrypted wallets (ishaanam)
493b813e17 wallet: ensure that the passphrase is not deleted from memory when being used to rescan (ishaanam)
66a86ebabb wallet: keep track of when the passphrase is needed when rescanning (ishaanam)
Pull request description:
Wallet passphrases are needed to top up the keypool of encrypted wallets
during a rescan. The following RPCs need the passphrase when rescanning:
- `importdescriptors`
- `rescanblockchain`
The following RPCs use the information about whether or not the
passphrase is being used to ensure that full rescans are able to
take place (meaning the following RPCs should not be able to run
if a rescan requiring the wallet to be unlocked is taking place):
- `walletlock`
- `encryptwallet`
- `walletpassphrasechange`
`m_relock_mutex` is also introduced so that the passphrase is not
deleted from memory when the timeout provided in
`walletpassphrase` is up and the wallet is still rescanning.
Fixes #25702, #11249
Thanks to achow101 for coming up with the idea of using a new mutex to solve this issue and for answering related questions.
ACKs for top commit:
achow101:
ACK 6a5b348f2e
hernanmarino:
ACK 6a5b348f2e
furszy:
Tested ACK 6a5b348f
Tree-SHA512: 0b6db692714f6f94594fa47249f5ee24f85713bfa70ac295a7e84b9ca6c07dda65df7b47781a2dc73e5b603a8725343a2f864428ae20d3e126c5b4802abc4ab5
52f4d567d6 refactor: remove <util/system.h> include from wallet.h (furszy)
6c9b342c30 refactor: wallet, remove global 'ArgsManager' access (furszy)
d8f5fc4462 wallet: set '-walletnotify' script instead of access global args manager (furszy)
3477a28dd3 wallet: set keypool_size instead of access global args manager (furszy)
Pull request description:
Structurally, the wallet class shouldn't access the global `ArgsManager` class, its internal behavior shouldn't be coupled to a global command line args parsing object.
So this PR migrates the only two places where we depend on it: (1) the keypool size, and (2) the "-walletnotify" script. And cleans up the, now unneeded, wallet `ArgsManager` ref member.
Extra note:
In the process of removing the args ref member, discovered and fixed files that were invalidly depending on the wallet header including `util/system.h`.
ACKs for top commit:
achow101:
ACK 52f4d567d6
TheCharlatan:
Re-ACK 52f4d567d6
hebasto:
re-ACK 52f4d567d6
Tree-SHA512: 0cffd99b4dd4864bf618aa45aeaabbef2b6441d27b6dbb03489c4e013330877682ff17b418d07aa25fbe1040bdf2c67d7559bdeb84128c5437bf0e6247719016
Since migration reloads the wallet, the wallet will always be locked
unless the passphrase is given. migratewallet can now take the
passphrase in order to unlock the wallet for migration.
An overload of MigrateLegacyToDescriptor is added which takes the wallet
name. The original that took a wallet pointer is still available, it
just gets the name, closes the wallet, and calls the new overload.
Since we no longer store a ref to the global `ArgsManager`
inside the wallet, we can move the util/system.h
include to the cpp.
This dependency removal opened a can of worms, as few
other places were, invalidly, depending on the wallet's
header including it.
`m_relock_mutex` is introduced so that the passphrase is not
deleted from memory when the timeout provided in
`walletpassphrase` is up, but the wallet is still rescanning.
When an encrypted wallet is locked (for instance via the
RPC `walletlock`), the docs indicate that the key is
removed from memory. However, the vector (with a secure
allocator) is merely cleared. This allows the key to persist
indefinitely in memory. Instead, manually fill the bytes with
zeroes before clearing.
6d31900e52 wallet: migrate wallet, exit early if no legacy data exist (furszy)
Pull request description:
The process first creates a backup file then return an error,
without removing the recently created file, when notices that
the db is already running sqlite.
ACKs for top commit:
john-moffett:
ACK 6d31900e52
achow101:
ACK 6d31900e52
ishaanam:
crACK 6d31900e52
Tree-SHA512: 9fb52e80de96e129487ab91bef13647bc4570a782003b1e37940e2a00ca26283fd24ad39bdb63a984ae0a56140b518fd0d74aa2fc59ab04405b2c179b7d3c54a
b0fa5989e1 test: Check that orphaned coinbase unconf spend is still abandoned (Andrew Chow)
9addbd7890 wallet: Automatically abandon orphaned coinbases and their children (Andrew Chow)
Pull request description:
When a block is reorged out of the main chain, any descendants of the coinbase will no longer be valid. Currently they are only marked as inactive, which means that our balance calculations will still include them. In order to be excluded from the balance calculation, they need to either be abandoned or conflicted. This PR goes with the abandoned method.
Note that even when they are included in balance calculations, coin selection will not select outputs belonging to these transactions because they are not in the mempool.
Fixes #14148
ACKs for top commit:
furszy:
ACK b0fa5989 with a not-blocking nit.
aureleoules:
reACK b0fa5989e1
ishaanam:
ACK b0fa5989e1
Tree-SHA512: 68f12e7aa8df392d8817dc6ac0becce8dbe83837bfa538f47027e6730e5b2e1b1a090cfcea2dc598398fdb66090e02d321d799f087020d7e1badcf96e598c3ac
4aebd832a4 db: Change DatabaseCursor::Next to return status enum (Andrew Chow)
d79e8dcf29 wallet: Have cursor users use DatabaseCursor directly (Andrew Chow)
7a198bba0a wallet: Introduce DatabaseCursor RAII class for managing cursor (Andrew Chow)
69efbc011b Move SafeDbt out of BerkeleyBatch (Andrew Chow)
Pull request description:
Instead of having database cursors be tied to a particular `DatabaseBatch` object and requiring its setup and teardown be separate functions in that batch, we can have cursors be separate RAII classes. This makes it easier to create and destroy cursors as well as having cursors that have slightly different behaviors.
Additionally, since reading data from a cursor is a tri-state, this PR changes the return value of the `Next` function (formerly `ReadAtCursor`) to return an Enum rather than the current system of 2 booleans. This greatly simplifies and unifies the code that deals with cursors as now there is no confusion as to what the function returns when there are no records left to be read.
Extracted from #24914
ACKs for top commit:
furszy:
diff ACK 4aebd83
theStack:
Code-review ACK 4aebd832a4
Tree-SHA512: 5d0be56a18de5b08c777dd5a73ba5a6ef1e696fdb07d1dca952a88ded07887b7c5c04342f9a76feb2f6fe24a45dc31f094f1f5d9500e6bdf4a44f4edb66dcaa1
f9ce0eadf4 For feebump, ignore abandoned descendant spends (John Moffett)
Pull request description:
Closes #26667
To be eligible for fee-bumping, a transaction must not have any of its outputs (eg - change) spent in other unconfirmed transactions in the wallet. This behavior is currently [enforced](9e229a542f/src/wallet/feebumper.cpp (L25-L28)) and [tested](9e229a542f/test/functional/wallet_bumpfee.py (L270-L286)).
However, this check shouldn't apply to spends in abandoned descendant transactions, as explained by #26667.
`CWallet::IsSpent` already carves out an exception for abandoned transactions, so we can just use that.
I've also added a new test to cover this case.
ACKs for top commit:
Sjors:
re-utACK f9ce0eadf4
achow101:
ACK f9ce0eadf4
furszy:
ACK f9ce0ead
Tree-SHA512: 19d957d1cf6747668bb114e27a305027bfca5a9bed2b1d9cc9e1b0bd4666486c7c4b60b045a7fe677eb9734d746f5de76390781fb1e9e0bceb4a46d20acd1749
3784009534 wallet: Skip rescanning if wallet is more recent than tip (Andrew Chow)
Pull request description:
If a wallet has key birthdates that are more recent than the currrent chain tip, or a bestblock height higher than the current tip, we should not attempt to rescan as there is nothing to scan for.
Fixes #26655
ACKs for top commit:
ishaanam:
re-utACK 3784009534
w0xlt:
utACK 3784009534
furszy:
Code review ACK 37840095
Tree-SHA512: f0d90b62940d97d50f21e1e01fa6dcb54409fad819cea4283612825c4d93d733df323cd92787fed43956b0a8e386a5bf88218f1f5749c913398667a5c8f54470
730e14a317 test: wallet: check that labels are migrated to watchonly wallet (Sebastian Falbesoner)
d5f4ae7fac wallet: fully migrate address book entries for watchonly/solvable wallets (Sebastian Falbesoner)
Pull request description:
Currently `migratewallet` migrates the address book (i.e. labels and purposes) for watchonly and solvable wallets only in RAM, but doesn't persist them on disk. Fix this by adding another loop for both of the special wallet types after which writes the corresponding NAME and PURPOSE entries to the database in a single batch. Also adds a corresponding test that checks if labels were migrated correctly for a watchonly wallet.
ACKs for top commit:
achow101:
ACK 730e14a317
furszy:
code ACK 730e14a3, left a non-blocking nit.
aureleoules:
ACK 730e14a317
Tree-SHA512: 159487e11e858924ef762e0190ccaea185bdff239e3d2280c8d63c4ac2649ec71714dc4d53dec644f03488f91c3b4bbbbf3434dad23bc0fcecb6657f353ea766
21ad4e26ec test: add coverage for cross-chain wallet restore (Sebastian Falbesoner)
8c7222bda3 wallet: fix GUI crash on cross-chain legacy wallet restore (Sebastian Falbesoner)
Pull request description:
Restoring a wallet backup from another chain should result in a dedicated error message (we have _"Wallet files should not be reused across chains. Restart bitcoind with -walletcrosschain to override."_ for that). Unfortunately this is currently not the case for legacy wallet restores, as in the course of cleaning up the newly created wallet directory a `filesystem_error` exception is thrown due to the directory not being empty; the wallet database did indeed load successfully (otherwise we wouldn't know that the chain doesn't match) and hence BDB-related files and directories are already created in the wallet directory.
For bitcoind, this leads to a very confusing error message:
```
$ ./src/bitcoin-cli restorewallet test123 ~/.bitcoin/regtest/wallets/regtest_wallet/wallet.dat
error code: -1
error message: filesystem error: in remove: Directory not empty ["/home/thestack/.bitcoin/wallets/test123"]
```
Even worse, the GUI crashes in such a scenario:
```
libc++abi: terminating with uncaught exception of type std::__1::__fs::filesystem::filesystem_error: filesystem error: in remove: Directory not empty ["/home/thestack/.bitcoin/wallets/foobar"]
Abort trap (core dumped)
```
Fix this by simply deleting the whole folder via `fs::remove_all`. With this, the expected error message appears both for the `restorewallet` RPC call and in the GUI (as a message-box):
```
$ ./src/bitcoin-cli restorewallet test123 ~/.bitcoin/regtest/wallets/regtest_wallet/wallet.dat
error code: -4
error message:
Wallet loading failed. Wallet files should not be reused across chains. Restart bitcoind with -walletcrosschain to override.
```
ACKs for top commit:
achow101:
ACK 21ad4e26ec
aureleoules:
ACK 21ad4e26ec
furszy:
utACK 21ad4e26
Tree-SHA512: 313f6494c2fbe823bff9b975cb2d9410bb518977a1e59a5159ee9836bc012947fa50b56be0e41b1a2f50d9c0c7f4fddfdf4fbe479d8a59a6ee44bb389c804abc
55696a0ac3 wallet: remove `mempool_sequence` from `transactionRemovedFromMempool` (w0xlt)
bf19069c53 wallet: remove `mempool_sequence` from `transactionAddedToMempool` (w0xlt)
Pull request description:
This PR removes `mempool_sequence` from `transactionRemovedFromMempool` and `transactionAddedToMempool`.
`mempool_sequence` is not used in these methods, only in ZMQ notifications.
ACKs for top commit:
instagibbs:
ACK 55696a0ac3
Tree-SHA512: 621e89230bcb6edfed83e2758601a2b093822fc2dc4e9bfb00487e340f2bc4c5ac3bf6df3ca00b7fe55bb3df15858820f2bf698f403d2e48b915dd9eb47b63e0
Currently `migratewallet` migrates the address book (i.e. labels and
purposes) for watchonly and solvable wallets only in RAM, but doesn't
persist them on disk. Fix this by adding another loop for both of the
special wallet types after which writes the corresponding NAME and
PURPOSE entries to the database in a single batch.
Restoring a wallet backup from another chain should obviously result
in a dedicated error message (we have "Wallet files should not be
reused across chains. Restart bitcoind with -walletcrosschain to
override." for that). Unfortunately this is currently not the case
for legacy wallet restores, as in the course of cleaning up the
newly created wallet directory a `filesystem_error` exception is
thrown due to the directory not being empty; the wallet database did
indeed load successfully (otherwise we wouldn't know that the chain doesn't
match) and hence BDB-related files and directories are created in the wallet
directory.
For bitcoind, this leads to a very confusing error message:
```
$ ./src/bitcoin-cli restorewallet test123 ~/.bitcoin/regtest/wallets/regtest_wallet/wallet.dat
error code: -1
error message: filesystem error: in remove: Directory not empty ["/home/thestack/.bitcoin/wallets/test123"]
```
Even worse, the GUI crashes in such a scenario:
```
libc++abi: terminating with uncaught exception of type std::__1::__fs::filesystem::filesystem_error: filesystem error: in remove: Directory not empty ["/home/thestack/.bitcoin/wallets/foobar"]
Abort trap (core dumped)
```
Fix this by simply deleting the whole folder via `fs::remove_all`.
Next()'s result is a tri-state - failed, more to go, complete. Replace
the way that this is returned with an enum with values FAIL, MORE, and
DONE rather than with two booleans.
To be eligible for fee-bumping, a transaction must not have any
of its outputs (eg - change) spent in other unconfirmed transactions
in the wallet. However, this check should not apply to abandoned
transactions.
A new test case is added to cover this case.
If a wallet has key birthdates that are more recent than the currrent
chain tip, or a bestblock height higher than the current tip, we should
not attempt to rescan as there is nothing to scan for.
b19c4124b3 refactor: Rename ambiguous interfaces::MakeHandler functions (Ryan Ofsky)
dd6e8bd71c build: remove BOOST_CPPFLAGS from libbitcoin_util (fanquake)
82e272a109 refactor: Move src/interfaces/*.cpp files to libbitcoin_common.a (Ryan Ofsky)
Pull request description:
These belong in `libbitcoin_common.a`, not `libbitcoin_util.a`, because they aren't general-purpose utilities, they just contain some common glue code that is used by both the node and the wallet. Another reason not to include these in `libbitcoin_util.a` is to prevent them from being used by the kernel library.
Also rename ambiguous `MakeHandler` functions to `MakeCleanupHandler` and `MakeSignalHandler`. Cleanup function handler was introduced after boost signals handler, so original naming didn't make much sense.
This just contains a move-only commit, and a rename commit. There are no actual code or behavior changes.
This PR is an alternative to #26293, and solves the same issue of removing a boost dependency from the _util_ library. The advantages of this PR compared to #26293 are that it keeps the source directory structure more flat, and it avoids having to change #includes all over the codebase.
ACKs for top commit:
hebasto:
ACK b19c4124b3
Tree-SHA512: b3a1d33eedceda7ad852c6d6f35700159d156d96071e59acae2bc325467fef81476f860a8855ea39cf3ea706a1df2a341f34fb2dcb032c31a3b0e9cf14103b6a
203886c443 Fixup clang-tidy named argument comments (fanquake)
Pull request description:
Fix comments so they are checked/consistent.
Fix incorrect comments.
ACKs for top commit:
hebasto:
ACK 203886c443, I have reviewed the code and it looks OK, I agree it can be merged.
Tree-SHA512: e1257840f91fe39842e2b19299c1633604697b8584fe44b1977ada33cdde5433c877ed0b669fa334e20b04971dc89cd47d58b2783b6f7004521f01d05a1245da
3198e4239e test: check that loading descriptor wallet with legacy entries throws error (Sebastian Falbesoner)
349ed2a0ee wallet: throw error if legacy entries are present on loading descriptor wallets (Sebastian Falbesoner)
Pull request description:
Loading a descriptor wallet currently leads to a segfault if a legacy key type entry is present that can be deserialized successfully and needs SPKman-interaction. To reproduce with a "cscript" entry (see second commit for details):
```
$ ./src/bitcoin-cli createwallet crashme
$ ./src/bitcoin-cli unloadwallet crashme
$ sqlite3 ~/.bitcoin/wallets/crashme/wallet.dat
SQLite version 3.38.2 2022-03-26 13:51:10
Enter ".help" for usage hints.
sqlite> INSERT INTO main VALUES(x'07637363726970740000000000000000000000000000000000000000', x'00');
$ ./src/bitcoin-cli loadwallet crashme
--- bitcoind output: ---
2022-11-06T13:51:01Z Using SQLite Version 3.38.2
2022-11-06T13:51:01Z Using wallet /home/honey/.bitcoin/wallets/crashme
2022-11-06T13:51:01Z init message: Loading wallet…
2022-11-06T13:51:01Z [crashme] Wallet file version = 10500, last client version = 249900
Segmentation fault (core dumped)
```
Background: In the wallet key-value-loading routine, most legacy type entries require a `LegacyScriptPubKeyMan` instance after successful deserialization. On a descriptor wallet, creating that (via method `GetOrCreateLegacyScriptPubKeyMan`) fails and then leads to a null-pointer dereference crash. E.g. for CSCRIPT: 50422b770a/src/wallet/walletdb.cpp (L589-L594)
~~This PR fixes this by simply ignoring legacy entries if the wallet flags indicate that we have a descriptor wallet. The second commits adds a regression test to the descriptor wallet's functional test (fortunately Python includes sqlite3 support in the standard library).~~
~~Probably it would be even better to throw a warning to the user if unexpected legacy entries are found in descriptor wallets, but I think as a first mitigation everything is obvisouly better than crashing. As far as I'm aware, descriptor wallets created/migrated by Bitcoin Core should never end up in a state containing legacy type entries though.~~
This PR fixes this by throwing an error if legacy entries are found in descriptor wallets on loading.
ACKs for top commit:
achow101:
ACK 3198e4239e
aureleoules:
ACK 3198e4239e
Tree-SHA512: ee43da3f61248e0fde55d9a705869202cb83df678ebf4816f0e77263f0beac0d7bae9490465d1753159efb093ee37182931d76b2e2b6e8c6f8761285700ace1c
5e65a216d1 wallet: Explicitly say migratewallet on encrypted wallets is unsupported (Andrew Chow)
88afc73ae0 tests: Test for migrating encrypted wallets (Andrew Chow)
86ef7b3c7b wallet: Avoid null pointer deref when cleaning up migratewallet (Andrew Chow)
Pull request description:
When `migratewallet` fails, we do an automatic cleanup in order to reset everything so that the user does not experience any interruptions. However, this apparently has a segfault in it, caused by the the pointers to the watchonly and solvables wallets being nullptr. If those wallets are not created (either not needed, or failed early on), we will accidentally attempt to dereference these nullptrs, which causes a segfault.
This failure can be easily reached by trying to migrate an encrypted wallet. Currently, we can't migrate encrypted wallets because of how we unload wallets before migrating, and therefore forget the encryption key if the wallet was unlocked. So any encrypted wallets will fail, entering the cleanup, and because watchonly and solvables wallets don't exist yet, the segfault is reached.
This PR fixes this by not putting those nullptrs in a place that we will end up dereferencing them later. It also adds a test that uses the encrypted wallet issue.
ACKs for top commit:
S3RK:
reACK 5e65a216d1
stickies-v:
ACK [5e65a21](5e65a216d1)
furszy:
diff ACK 5e65a21
Tree-SHA512: f75643797220d4232ad3ab8cb4b46d0f3667f00486e910ca748c9b6d174d446968f1ec4dd7f907da1be9566088849da7edcd8cd8f12de671c3241b513deb8e80
If migratewallet fails, we do a cleanup which removes the watchonly and
solvables wallets if they were created. However, if they were not, their
pointers are nullptr and we don't check for that, which causes a
segfault during the cleanup. So check that they aren't nullptr before
cleaning them up.
In the wallet key-value-loading routine, most legacy type entries
require a LegacyScriptPubKeyMan instance after successful
deserialization. On a descriptor wallet, creating that (via method
`GetOrCreateLegacyScriptPubKeyMan`) fails and then leads to a
null-pointer dereference crash. Fix this by throwing an error if
if the wallet flags indicate that we have a descriptor wallet and there
is a legacy entry found.
0582932260 test: add test for fast rescan using block filters (top-up detection) (Sebastian Falbesoner)
ca48a4694f rpc: doc: mention rescan speedup using `blockfilterindex=1` in affected wallet RPCs (Sebastian Falbesoner)
3449880b49 wallet: fast rescan: show log message for every non-skipped block (Sebastian Falbesoner)
935c6c4b23 wallet: take use of `FastWalletRescanFilter` (Sebastian Falbesoner)
70b3513904 wallet: add `FastWalletRescanFilter` class for speeding up rescans (Sebastian Falbesoner)
c051026586 wallet: add method for retrieving the end range for a ScriptPubKeyMan (Sebastian Falbesoner)
845279132b wallet: support fetching scriptPubKeys with minimum descriptor range index (Sebastian Falbesoner)
088e38d3bb add chain interface methods for using BIP 157 block filters (Sebastian Falbesoner)
Pull request description:
## Description
This PR is another take of using BIP 157 block filters (enabled by `-blockfilterindex=1`) for faster wallet rescans and is a modern revival of #15845. For reviewers new to this topic I can highly recommend to read the corresponding PR review club (https://bitcoincore.reviews/15845).
The basic idea is to skip blocks for deeper inspection (i.e. looking at every single tx for matches) if our block filter doesn't match any of the block's spent or created UTXOs are relevant for our wallet. Note that there can be false-positives (see https://bitcoincore.reviews/15845#l-199 for a PR review club discussion about false-positive rates), but no false-negatives, i.e. it is safe to skip blocks if the filter doesn't match; if the filter *does* match even though there are no wallet-relevant txs in the block, no harm is done, only a little more time is spent extra.
In contrast to #15845, this solution only supports descriptor wallets, which are way more widespread now than back in the time >3 years ago. With that approach, we don't have to ever derive the relevant scriptPubKeys ourselves from keys before populating the filter, and can instead shift the full responsibility to that to the `DescriptorScriptPubKeyMan` which already takes care of that automatically. Compared to legacy wallets, the `IsMine` logic for descriptor wallets is as trivial as checking if a scriptPubKey is included in the ScriptPubKeyMan's set of scriptPubKeys (`m_map_script_pub_keys`): e191fac4f3/src/wallet/scriptpubkeyman.cpp (L1703-L1710)
One of the unaddressed issues of #15845 was that [the filter was only created once outside the loop](https://github.com/bitcoin/bitcoin/pull/15845#discussion_r343265997) and as such didn't take into account possible top-ups that have happened. This is solved here by keeping a state of ranged `DescriptorScriptPubKeyMan`'s descriptor end ranges and check at each iteration whether that range has increased since last time. If yes, we update the filter with all scriptPubKeys that have been added since the last filter update with a range index equal or higher than the last end range. Note that finding new scriptPubKeys could be made more efficient than linearly iterating through the whole `m_script_pub_keys` map (e.g. by introducing a bidirectional map), but this would mean introducing additional complexity and state and it's probably not worth it at this time, considering that the performance gain is already significant.
Output scripts from non-ranged `DescriptorScriptPubKeyMan`s (i.e. ones with a fixed set of output scripts that is never extended) are added only once when the filter is created first.
## Benchmark results
Obviously, the speed-up indirectly correlates with the wallet tx frequency in the scanned range: the more blocks contain wallet-related transactions, the less blocks can be skipped due to block filter detection.
In a [simple benchmark](https://github.com/theStack/bitcoin/blob/fast_rescan_functional_test_benchmark/test/functional/pr25957_benchmark.py), a regtest chain with 1008 blocks (corresponding to 1 week) is mined with 20000 scriptPubKeys contained (25 txs * 800 outputs) each. The blocks each have a weight of ~2500000 WUs and hence are about 62.5% full. A global constant `WALLET_TX_BLOCK_FREQUENCY` defines how often wallet-related txs are included in a block. The created descriptor wallet (default setting of `keypool=1000`, we have 8*1000 = 8000 scriptPubKeys at the start) is backuped via the `backupwallet` RPC before the mining starts and imported via `restorewallet` RPC after. The measured time for taking this import process (which involves a rescan) once with block filters (`-blockfilterindex=1`) and once without block filters (`-blockfilterindex=0`) yield the relevant result numbers for the benchmark.
The following table lists the results, sorted from worst-case (all blocks contain wallte-relevant txs, 0% can be skipped) to best-case (no blocks contain walltet-relevant txs, 100% can be skipped) where the frequencies have been picked arbitrarily:
wallet-related tx frequency; 1 tx per... | ratio of irrelevant blocks | w/o filters | with filters | speed gain
--------------------------------------------|-----------------------------|-------------|--------------|-------------
~ 10 minutes (every block) | 0% | 56.806s | 63.554s | ~0.9x
~ 20 minutes (every 2nd block) | 50% (1/2) | 58.896s | 36.076s | ~1.6x
~ 30 minutes (every 3rd block) | 66.67% (2/3) | 56.781s | 25.430s | ~2.2x
~ 1 hour (every 6th block) | 83.33% (5/6) | 58.193s | 15.786s | ~3.7x
~ 6 hours (every 36th block) | 97.22% (35/36) | 57.500s | 6.935s | ~8.3x
~ 1 day (every 144th block) | 99.31% (143/144) | 68.881s | 6.107s | ~11.3x
(no txs) | 100% | 58.529s | 5.630s | ~10.4x
Since even the (rather unrealistic) worst-case scenario of having wallet-related txs in _every_ block of the rescan range obviously doesn't take significantly longer, I'd argue it's reasonable to always take advantage of block filters if they are available and there's no need to provide an option for the user.
Feedback about the general approach (but also about details like naming, where I struggled a lot) would be greatly appreciated. Thanks fly out to furszy for discussing this subject and patiently answering basic question about descriptor wallets!
ACKs for top commit:
achow101:
ACK 0582932260
Sjors:
re-utACK 0582932260
aureleoules:
ACK 0582932260 - minor changes, documentation and updated test since last review
w0xlt:
re-ACK 0582932260
Tree-SHA512: 3289ba6e4572726e915d19f3e8b251d12a4cec8c96d041589956c484b5575e3708b14f6e1e121b05fe98aff1c8724de4564a5a9123f876967d33343cbef242e1
