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
3eb041f014 wallet: Change coin selection fee assert to error (Andrew Chow)
c6e7f224c1 util: Add StrFormatInternalBug and STR_INTERNAL_BUG (MarcoFalke)
Pull request description:
Returning an error instead of asserting for the low fee check will be better as it does not crash the node and instructs users to report the bug.
ACKs for top commit:
S3RK:
ACK 3eb041f014
aureleoules:
ACK 3eb041f014
furszy:
ACK 3eb041f0
Tree-SHA512: 118c13d7cdfce492080edd4cb12e6d960695377b978c7573f9c58b6d918664afd0e8e591eed0605d08ac756fa8eceed456349de5f3a025174069abf369bb5a5f
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
7362f8e5e2 refactor: make CoinsResult total amounts members private (furszy)
3282fad599 wallet: add assert to SelectionResult::Merge for safety (S3RK)
c4e3b7d6a1 wallet: SelectCoins, return early if wallet's UTXOs cannot cover the target (furszy)
cac2725fd0 test: bugfix, coinselector_test, use 'CoinsResult::Erase/Add' instead of direct member access (furszy)
cf79384697 test: Coin Selection, duplicated preset inputs selection (furszy)
341ba7ffd8 test: wallet, coverage for CoinsResult::Erase function (furszy)
f930aefff9 wallet: bugfix, 'CoinsResult::Erase' is erasing only one output of the set (furszy)
Pull request description:
This comes with #26559.
Solving few bugs inside the wallet's transaction creation
process and adding test coverage for them.
Plus, making use of the `CoinsResult::total_amount` cached value
inside the Coin Selection process to return early if we don't have
enough funds to cover the target amount.
### Bugs
1) The `CoinsResult::Erase` method removes only one
output from the available coins vector (there is a [loop break](c1061be14a/src/wallet/spend.cpp (L112))
that should have never been there) and not all the preset inputs.
Which on master is not a problem, because since [#25685](https://github.com/bitcoin/bitcoin/pull/25685)
we are no longer using the method. But, it's a bug on v24
(check [#26559](https://github.com/bitcoin/bitcoin/pull/26559)).
This method it's being fixed and not removed because I'm later using it to solve
another bug inside this PR.
2) As we update the total cached amount of the `CoinsResult` object inside
`AvailableCoins` and we don't use such function inside the coin selection
tests (we manually load up the `CoinsResult` object), there is a discrepancy
between the outputs that we add/erase and the total amount cached value.
### Improvements
* This makes use of the `CoinsResult` total amount field to early return
with an "Insufficient funds" error inside Coin Selection if the tx target
amount is greater than the sum of all the wallet available coins plus the
preset inputs amounts (we don't need to perform the entire coin selection
process if we already know that there aren't enough funds inside our wallet).
### Test Coverage
1) Adds test coverage for the duplicated preset input selection bug that we have in v24.
Where the wallet invalidly selects the preset inputs twice during the Coin Selection
process. Which ends up with a "good" Coin Selection result that does not cover the
total tx target amount. Which, alone, crashes the wallet due an insane fee.
But.. to make it worst, adding the subtract fee from output functionality
to this mix ends up with the wallet by-passing the "insane" fee assertion,
decreasing the output amount to fulfill the insane fee, and.. sadly,
broadcasting the tx to the network.
2) Adds test coverage for the `CoinsResult::Erase` method.
------------------------------------
TO DO:
* [ ] Update [#26559 ](https://github.com/bitcoin/bitcoin/pull/26559) description.
ACKs for top commit:
achow101:
ACK 7362f8e5e2
glozow:
ACK 7362f8e5e2, I assume there will be a followup PR to add coin selection sanity checks and we can discuss the best way to do that there.
josibake:
ACK [7362f8e](7362f8e5e2)
Tree-SHA512: 37a6828ea10d8d36c8d5873ceede7c8bef72ae4c34bef21721fa9dad83ad6dba93711c3170a26ab6e05bdbc267bb17433da08ccb83b82956d05fb16090328cba
The CoinsResult class will now count the raw total amount and the effective
total amount internally (inside the 'CoinsResult::Add' and 'CoinsResult::Erase'
methods).
So there is no discrepancy between what we add/erase and the total values.
(which is what was happening on the coinselector_test because the 'CoinsResult'
object is manually created there, and we were not keeping the total amount
in sync with the outputs being added/removed).
Aside from the cleanup, this solves a bug in the following-up commit. Because, in these
tests, we are manually adding/erasing outputs from the CoinsResult object but never
updating the internal total amount field.
This exercises the bug inside CoinsResult::Erase that
ends up on (1) a wallet crash or (2) a created and
broadcasted tx that contains a reduced recipient's amount.
This is covered by making the wallet selects the preset
inputs twice during the coin selection process.
Making the wallet think that the selection process result covers
the entire tx target when it does not. It's actually creating
a tx that sends more coins than what inputs are covering for.
Which, combined with the SFFO option, makes the wallet
incorrectly reduce the recipient's amount by the difference
between the original target and the wrongly counted inputs.
Which means, a created and relayed tx sending less coins to
the destination than what the user inputted.
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
1b77db2653 test: add `ismine` test for descriptor scriptpubkeyman (w0xlt)
Pull request description:
Currently `src/wallet/test/ismine_tests.cpp` has tests for the legacy ScriptPubKeyMan only.
This PR adds tests for the descriptor ScriptPubKeyMan.
ACKs for top commit:
ishaanam:
ACK 1b77db2653
achow101:
ACK 1b77db2653
furszy:
ACK 1b77db26 with a non-blocking comment.
Tree-SHA512: 977b5d1e71f9468331aeb4ebaf3708dd651f9f3018d4544a395b87ca6d7fb8bfa6d20acc1a4f6e096e240e81d30fb7a6e8add190e52536e7a3cb5a80f392883f
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.
Adds test coverage for the wallet's crypted key loading from db process.
The following scenarios are covered:
1) "All ckeys checksums valid" test:
Loads an encrypted wallet with all the crypted keys with a valid checksum and
verifies that 'CWallet::Unlock' doesn't force an entire crypted keys re-write.
(we force a complete ckeys re-write if we find any missing crypted key checksum
during the wallet loading process)
2) "Missing checksum in one ckey" test:
Verifies that loading up a wallet with, at least one, 'ckey' with no checksum
triggers a complete re-write of the crypted keys.
3) "Invalid ckey checksum error" test:
Verifies that loading up a ckey with an invalid checksum stops the wallet loading
process with a corruption error.
4) "Invalid ckey pubkey error" test:
Verifies that loading up a ckey with an invalid pubkey stops the wallet loading
process with a corruption error.
files share the same purpose, and we shouldn't have wallet code
inside the test directory.
This later is needed to use wallet util functions in the bench
and test binaries without be forced to duplicate them.
At wallet load time, we set the crypted key "checksum_valid" variable always to false.
Which, on every wallet decryption call, forces the process to re-write the entire ckeys to db when
it's not needed.
fa84df1f03 scripted-diff: wallet: rename AvailableCoinsParams members to snake_case (furszy)
61c2265629 wallet: group AvailableCoins filtering parameters in a single struct (furszy)
f0f6a3577b RPC: listunspent, add "include immature coinbase" flag (furszy)
Pull request description:
Simple PR; adds a "include_immature_coinbase" flag to `listunspent` to include the immature coinbase UTXOs on the response. Requested by #25728.
ACKs for top commit:
danielabrozzoni:
reACK fa84df1f03
achow101:
ACK fa84df1f03
aureleoules:
reACK fa84df1f03
kouloumos:
reACK fa84df1f03
theStack:
Code-review ACK fa84df1f03
Tree-SHA512: 0f3544cb8cfd0378a5c74594480f78e9e919c6cfb73a83e0f3112f8a0132a9147cf846f999eab522cea9ef5bd3ffd60690ea2ca367dde457b0554d7f38aec792
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.
c3b1fe59db rpc: doc: add missing option "bech32m" for `change_type` parameters (Sebastian Falbesoner)
Pull request description:
Affects the help of the `fundrawtransaction`, `send` and `walletcreatefundedpsbt` RPCs.
This was found by manually inspecting the results of `$ git grep p2sh-segwit.*bech32`.
ACKs for top commit:
achow101:
ACK c3b1fe59db
Tree-SHA512: a3f1f8fde5905c80e1b95bd042ca0bc73d08c1c0e79c52ab0d6d12d7afdd4aa288afb41e12279fcea328a396f3d0a5564018170c0a11c5aa26dc6d44d2a62b1c
0de30ed509 tests: Test Taproot PSBT signing with keys in other descriptor (Andrew Chow)
6efcdf6b7f tests: Use new wallets for each test in wallet_taproot.py (Andrew Chow)
8781a1b6bb psbt: Include output pubkey in additional pubkeys to sign (Andrew Chow)
323890d0d7 sign: Fill in taproot pubkey info for all script path sigs (Andrew Chow)
Pull request description:
A user reported on [stackexchange](https://bitcoin.stackexchange.com/q/115742/48884) that they were unable to sign for a `multi_a` script using a wallet that only had the corresponding keys (i.e. it did not have the `multi_a()` descriptor). This PR fixes this issue.
Additionally, `wallet_taproot.py` is modified to test for this scenario by having another wallet in `do_test_psbt` which contains descriptors that only have the keys involved in the descriptor being tested. `wallet_taproot.py` was also modified to create new wallets for each test case rather than sharing wallets throughout as the sharing could result in the signing wallet having the keys in a different descriptor and accidentally result in failing to detect a test failure.
The changes to the test also revealed a similar issue with `rawtr()` descriptors, which has also been fixed by checking if a descriptor can produce a `SigningProvider` for the Taproot output pubkey.
ACKs for top commit:
instagibbs:
crACK 0de30ed509
darosior:
ACK 0de30ed509
Tree-SHA512: 12e131dd8afd93da7b1288c9054de2415a228d4477b97102da3ee4e82ce9de20b186260c3085a4b7b067bd8b74400751dcadf153f113db83abc59e7466e69f14
In addition to the pubkeys in hd_keypaths and tap_bip32_keypaths, also
see if the descriptor can produce a SigningProvider for the output
pubkey.
Also slightly refactors this area to reduce code duplication.
3fcb545ab2 bench: benchmark transaction creation process (furszy)
a8a75346d7 wallet: SelectCoins, return early if target is covered by preset-inputs (furszy)
f41712a734 wallet: simplify preset inputs selection target check (furszy)
5baedc3351 wallet: remove fetch pre-selected-inputs responsibility from SelectCoins (furszy)
295852f619 wallet: encapsulate pre-selected-inputs lookup into its own function (furszy)
37e7887cb4 wallet: skip manually selected coins from 'AvailableCoins' result (furszy)
94c0766b0c wallet: skip available coins fetch if "other inputs" are disallowed (furszy)
Pull request description:
#### # Context (Current Flow on Master)
In the transaction creation process, in order to select which coins the new transaction will spend,
we first obtain all the available coins known by the wallet, which means walking-through the
wallet txes map, gathering the ones that fulfill certain spendability requirements in a vector.
This coins vector is then provided to the Coin Selection process, which first checks if the user
has manually selected any input (which could be internal, aka known by the wallet, or external),
and if it does, it fetches them by searching each of them inside the wallet and/or inside the
Coin Control external tx data.
Then, after finding the pre-selected-inputs and gathering them in a vector, the Coin Selection
process walks-through the entire available coins vector once more just to erase coins that are
in both vectors. So the Coin Selection process doesn’t pick them twice (duplicate inputs inside
the same transaction).
#### # Process Workflow Changes
Now, a new method, `FetchCoins` will be responsible for:
1) Lookup the user pre-selected-inputs (which can be internal or external).
2) And, fetch the available coins in the wallet (excluding the already fetched ones).
Which will occur prior to the Coin Selection process. Which allows us to never include the
pre-selected-inputs inside the available coins vector in the first place, as well as doing other
nice improvements (written below).
So, Coin Selection can perform its main responsibility without mixing it with having to fetch
internal/external coins nor any slow and unneeded duplicate coins verification.
#### # Summarizing the Improvements:
1) If any pre-selected-input lookup fail, the process will return the error right away.
(before, the wallet was fetching all the wallet available coins, walking through the
entire txes map, and then failing for an invalid pre-selected-input inside SelectCoins)
2) The pre-selected-inputs lookup failure causes are properly described on the return error.
(before, we were returning an "Insufficient Funds" error for everything, even if the failure
was due a not solvable external input)
3) **Faster Coin Selection**: no longer need to "remove the pre-set inputs from the available coins
vector so that Coin Selection doesn't pick them" (which meant to loop-over the entire
available coins vector at Coin Selection time, erasing duplicate coins that were pre-selected).
Now, the available coins vector, which is built after the pre-selected-inputs fetching,
doesn’t include the already selected inputs in the first place.
4) **Faster transaction creation** for transactions that only use manually selected inputs.
We now will return early, as soon as we finish fetching the pre-selected-inputs and
not perform the resources expensive calculation of walking-through the entire wallet
txes map to obtain the available coins (coins that we will not use).
---------------------------
Added a new bench (f6d0bb2) measuring the transaction creation process, for a wallet with ~250k UTXO, only using the pre-selected-inputs inside coin control. Setting `m_allow_other_inputs=false` to disallow the wallet to include coins automatically.
#### Result on this PR (tip f6d0bb2d):
| ns/op | op/s | err% | total | benchmark
|--------------------:|--------------------:|--------:|----------:|:----------
| 1,048,675.00 | 953.58 | 0.3% | 0.06 | `WalletCreateTransaction`
vs
#### Result on master (tip 4a4289e2):
| ns/op | op/s | err% | total | benchmark
|--------------------:|--------------------:|--------:|----------:|:----------
| 96,373,458.20 | 10.38 | 0.2% | 5.30 | `WalletCreateTransaction`
The benchmark took to run in master: **96.37 milliseconds**, while in this PR: **1 millisecond** 🚀 .
ACKs for top commit:
S3RK:
Code Review ACK 3fcb545ab2
achow101:
ACK 3fcb545ab2
aureleoules:
reACK 3fcb545ab2
Tree-SHA512: 42f833e92f40c348007ca565a4c98039e6f1ff25d8322bc2b27115824744779baf0b0a38452e4e2cdcba45076473f1028079bbd0f670020481ec5d3db42e4731
eb679a7896 rpc: make `address` field optional (w0xlt)
Pull request description:
Close https://github.com/bitcoin/bitcoin/issues/26338.
This PR makes optional the `address` field in the response of `listtransactions` and `listsinceblock` RPC.
And adds two tests that fail on master, but not on this branch.
ACKs for top commit:
achow101:
ACK eb679a7896
aureleoules:
ACK eb679a7896
Tree-SHA512: b267439626e2ec3134ae790c849949a4c40ef0cebd20092e8187be3db0a61941b2da10bbbba92ca880b8369f46c1aaa806d057eaa5159325f65cbec7cb33c52f
we are already computing the preset inputs total amount inside `PreSelectedInputs::Insert`,
which internally decides whether to use the effective value or the raw output value based on
the 'subtract_fee_outputs' flag.
so if there is an error in any of the pre-set coins, we can fail right away
without computing the wallet available coins set (calling `AvailableCoins`)
which is a slow operation as it goes through the entire wallet's txes map.
----------------------
And to make the Coin Selection flow cleared, have decoupled SelectCoins in two functions:
1) AutomaticCoinSelection.
2) SelectCoins.
1) AutomaticCoinSelection:
Receives a set of coins and selects the best subset of them to
cover the target amount.
2) SelectCoins
In charge of select all the user manually selected coins first ("pre-set inputs"), and
if coin_control 'm_allow_other_inputs=true', call 'AutomaticCoinSelection' to select a
subset of coins owned by the wallet to cover for the target - preset_inputs.total_amount
remaining value.
First step towards decoupling the pre-selected-inputs fetching functionality
from `SelectCoins`. Which, will let us not waste resources calculating the
available coins if one of the pre-set inputs has an error.
(right now, if one of the pre-set inputs is invalid, we first walk through
the entire wallet txes map just to end up failing right after it finish)
No need to walk through the entire wallet's txes map just to get
coins that we could have gotten by just doing a simple map.find(out.hash).
(Which is what we are doing inside `SelectCoins` anyway)
no need to waste resources calculating the wallet available coins if
they are not going to be used.
The 'm_allow_other_inputs=true` default value change is to correct
an ugly misleading behavior:
The tx creation process was having a workaround patch to automatically
fall back to select coins from the wallet if `m_allow_other_inputs=false`
(previous default value) and no manual inputs were selected.
This could be seen in master in flows like `sendtoaddress`, `sendmany`
and even the GUI, where the `m_allow_other_inputs` value isn't customized
and the wallet still selects and adds coins to the tx internally.
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
