fix for intermittent assertion error in getselectionwaste
introduced in f46275d011 as part of merge
for bitcoin/bitcoin#25647
the assertion would trigger in a fundrawtransaction call in
feature_confidential_transactions.py where the transaction inputs
included a non-policy asset.
during the loop in getselectionwaste, if the non-policy input waste was
calculated first the assertion would be triggered because
selected_effective_value has not yet met the selection target, because
non-policy coins have 0 effective value
the fix changed the assertion to an if statement, only adding to the
waste metric when selected_effective_value meets the target.
This was a difficult merge as always with diffs that touch spend.cpp and
createtransactioninternal. Added a FIXME NB for fundrawtransaction with
external outputs, which MUST be fixed before a new release.
Squash of 2 commits from https://github.com/ElementsProject/elements/pull/1258
- correct application of non_policy_effective_value to policy output in KnapsackSolver
- replace bad fee amount assert with error log and graceful failure in CWallet::CreateTransactionInternal
(cherry picked from commit 0f92a38254)
Update src/wallet/coinselection.cpp
Co-authored-by: Byron Hambly <byron@hambly.dev>
(cherry picked from commit cf0f56107b)
I discovered via fuzzing of another coin selection approach that at
extremely high feerates SRD may find input sets that lead to
transactions without change outputs. This is an unintended outcome since
SRD is meant to always produce a transaction with a change output—we use
other algorithms to specifically search for changeless solutions.
The issue occures when the flat allowance of 50,000 ṩ for change is
insufficient to pay for the creation of a change output with a non-dust
amount, at and above 1,613 ṩ/vB. Increasing the change budget by
change_fees makes SRD behave as expected at any feerates.
Since the kernel library no longer depends on the system file, move it
to the common library instead in accordance to the diagram in
doc/design/libraries.md.
be55f545d5 move-only: Extract common/args and common/config.cpp from util/system (TheCharlatan)
Pull request description:
This pull request is part of the `libbitcoinkernel` project https://github.com/bitcoin/bitcoin/issues/24303https://github.com/bitcoin/bitcoin/projects/18 and more specifically its "Step 2: Decouple most non-consensus code from libbitcoinkernel". It is part of a series of patches splitting up the `util/system` files. Its preceding pull request is https://github.com/bitcoin/bitcoin/pull/27254.
The pull request contains an extraction of ArgsManager related functions from util/system into their own common/ file.
The background of this commit is an ongoing effort to decouple the libbitcoinkernel library from the ArgsManager. The ArgsManager belongs into the common library, since the kernel library should not depend on it. See [doc/design/libraries.md](https://github.com/bitcoin/bitcoin/blob/master/doc/design/libraries.md) for more information on this rationale.
ACKs for top commit:
MarcoFalke:
re-ACK be55f545d5🚲
ryanofsky:
Code review ACK be55f545d5. Just small cleanups since the last review.
hebasto:
ACK be55f545d5, I have reviewed the code and it looks OK, I agree it can be merged.
Tree-SHA512: 90eb03334af0155b823030b4f2ecf286d35058d700ee2ddbbaa445be19e31eb0fe982656f35bd14ecee3ad2c3d0db3746855cb8f3777eff7253713e42873e111
25ab14712b refactor: coinselector_tests, unify wallet creation code (furszy)
ba9431c505 test: coverage for bnb max weight (furszy)
5a2bc45ee0 wallet: clean post coin selection max weight filter (furszy)
2d112584e3 coin selection: BnB, don't return selection if exceeds max allowed tx weight (furszy)
d3a1c098e4 test: coin selection, add coverage for SRD (furszy)
9d9689e5a6 coin selection: heap-ify SRD, don't return selection if exceeds max tx weight (furszy)
6107ec2229 coin selection: knapsack, select closest UTXO above target if result exceeds max tx size (furszy)
1284223691 wallet: refactor coin selection algos to return util::Result (furszy)
Pull request description:
Coming from the following comment https://github.com/bitcoin/bitcoin/pull/25729#discussion_r1029324367.
The reason why we are adding hundreds of UTXO from different sources when the target
amount is covered only by one of them is because only SRD returns a usable result.
Context:
In the test, we create 1515 UTXOs with 0.033 BTC each, and 1 UTXO with 50 BTC. Then
perform Coin Selection to fund 49.5 BTC.
As the selection of the 1515 small UTXOs exceeds the max allowed tx size, the
expectation here is to receive a selection result that only contain the big UTXO.
Which is not happening for the following reason:
Knapsack returns a result that exceeds the max allowed transaction size, when
it should return the closest utxo above the target, so we fallback to SRD who
selects coins randomly up until the target is met. So we end up with a selection
result with lot more coins than what is needed.
ACKs for top commit:
S3RK:
ACK 25ab14712b
achow101:
ACK 25ab14712b
Xekyo:
reACK 25ab14712b
theStack:
Code-review ACK 25ab14712b
Tree-SHA512: 2425de4cc479b4db999b3b2e02eb522a2130a06379cca0418672a51c4076971a1d427191173820db76a0f85a8edfff100114e1c38fb3b5dc51598d07cabe1a60
This is an extraction of ArgsManager related functions from util/system
into their own common file.
Config file related functions are moved to common/config.cpp.
The background of this commit is an ongoing effort to decouple the
libbitcoinkernel library from the ArgsManager. The ArgsManager belongs
into the common library, since the kernel library should not depend on
it. See doc/design/libraries.md for more information on this rationale.
Uses a min-effective-value heap, so we can remove the least valuable input/s
while the selected weight exceeds the maximum allowed weight.
Co-authored-by: Murch <murch@murch.one>
The simplest scenario where this is useful is on the 'check_max_weight' unit test
already:
We create 1515 UTXOs with 0.033 BTC each, and 1 UTXO with 50 BTC. Then perform
Coin Selection.
As the selection of the 1515 small UTXOs exceeds the max allowed tx size, the
expectation here is to receive a selection result that only contain the big
UTXO (which is not happening for the reasons stated below).
As knapsack returns a result that exceeds the max allowed transaction size, we
fallback to SRD, which selects coins randomly up until the target is met. So
we end up with a selection result with lot more coins than what is needed.
