Rename `BResult` class to `util::Result` and update the class interface to be
more compatible with `std::optional` and with a full-featured result class
implemented in https://github.com/bitcoin/bitcoin/pull/25665. Motivation for
this change is to update existing `BResult` usages now so they don't have to
change later when more features are added in #25665.
This change makes the following improvements originally implemented in #25665:
- More explicit API. Drops potentially misleading `BResult` constructor that
treats any bilingual string argument as an error. Adds `util::Error`
constructor so it is never ambiguous when a result is being assigned an error
or non-error value.
- Better type compatibility. Supports `util::Result<bilingual_str>` return
values to hold translated messages which are not errors.
- More standard and consistent API. `util::Result` supports most of the same
operators and methods as `std::optional`. `BResult` had a less familiar
interface with `HasRes`/`GetObj`/`ReleaseObj` methods. The Result/Res/Obj
naming was also not internally consistent.
- Better code organization. Puts `src/util/` code in the `util::` namespace so
naming reflects code organization and it is obvious where the class is coming
from. Drops "B" from name because it is undocumented what it stands for
(bilingual?)
- Has unit tests.
Pass the whole CoinsResult struct to SelectCoins instead of only a
vector. This means we now have to remove preselected coins from each
OutputType vector and shuffle each vector individually.
Pass the whole CoinsResult struct to AttemptSelection. This involves
moving the logic in AttemptSelection to a newly named function,
ChooseSelectionResult. This will allow us to run ChooseSelectionResult
over each OutputType in a later commit. This ensures the backoffs work
properly.
Update unit and bench tests to use CoinResult.
111ea3ab71 wallet: refactor GetNewDestination, use BResult (furszy)
22351725bc send: refactor CreateTransaction flow to return a BResult<CTransactionRef> (furszy)
198fcca162 wallet: refactor, include 'FeeCalculation' inside 'CreatedTransactionResult' (furszy)
7a45c33d1f Introduce generic 'Result' class (furszy)
Pull request description:
Based on a common function signature pattern that we have all around the sources:
```cpp
bool doSomething(arg1, arg2, arg3, arg4, &result_obj, &error_string) {
// do something...
if (error) {
error_string = "something bad happened";
return false;
}
result = goodResult;
return true;
}
```
Introduced a generic class `BResult` that encapsulate the function boolean result, the result object (in case of having it) and, in case of failure, the string error reason.
Obtaining in this way cleaner function signatures and removing boilerplate code:
```cpp
BResult<Obj> doSomething(arg1, arg2, arg3, arg4) {
// do something...
if (error) return "something bad happened";
return goodResult;
}
```
Same cleanup applies equally to the function callers' side as well. There is no longer need to add the error string and the result object declarations before calling the function:
Before:
```cpp
Obj result_obj;
std::string error_string;
if (!doSomething(arg1, arg2, arg3, arg4, result_obj, error_string)) {
LogPrintf("Error: %s", error_string);
}
return result_obj;
```
Now:
```cpp
BResult<Obj> op_res = doSomething(arg1, arg2, arg3, arg4);
if (!op_res) {
LogPrintf("Error: %s", op_res.GetError());
}
return op_res.GetObjResult();
```
### Initial Implementation:
Have connected this new concept to two different flows for now:
1) The `CreateTransaction` flow. --> 7ba2b87c
2) The `GetNewDestination` flow. --> bcee0912
Happy note: even when introduced a new class into the sources, the amount of lines removed is almost equal to added ones :).
Extra note: this work is an extended version (and a decoupling) of the work that is inside #24845 (which does not contain the `GetNewDestination` changes nor the inclusion of the `FeeCalculation` field inside `CreatedTransactionResult`).
ACKs for top commit:
achow101:
ACK 111ea3ab71
w0xlt:
reACK 111ea3ab71
theStack:
re-ACK 111ea3ab71
MarcoFalke:
review ACK 111ea3ab71🎏
Tree-SHA512: 6d84d901a4cb923727067f25ff64542a40edd1ea84fdeac092312ac684c34e3688a52ac5eb012717d2b73f4cb742b9d78e458eb0e9cb9d6d72a916395be91f69
98ea43d5e9 test: add tests for negative waste during coin selection (ishaanam)
Pull request description:
#25495 mentions that waste can be negative when the current feerate is less than the long term feerate. There are currently no waste tests for negative waste, so this PR adds two of them.
ACKs for top commit:
achow101:
ACK 98ea43d5e9
glozow:
light code review ACK 98ea43d5e9, good to have tests for negative waste
Tree-SHA512: d194d370f1257975959d3c601fea9f82c30c1aabc3e8bedc997c62659283fe681cc527e59df1a0187b3c91e8067c60374dd5ce0237561bd882edafe6a575a9b9
d54c5c8b1b wallet: use CCoinControl to estimate signature size (S3RK)
a94659c84e wallet: replace GetTxSpendSize with CalculateMaximumSignedInputSize (S3RK)
Pull request description:
Currently `DummySignTx` and `DummySignInput` use different ways to determine signature size.
This PR unifies the way wallet estimates signature size for various inputs.
Instead of passing boolean flags from calling code the `use_max_sig` is now calculated at the place of signature creation using information available in `CCoinControl`
ACKs for top commit:
achow101:
ACK d54c5c8b1b
theStack:
Code-review ACK d54c5c8b1b
Tree-SHA512: e790903ad4683067070aa7dbf7434a1bd142282a5bc425112e64d88d27559f1a2cd60c68d6022feaf6b845237035cb18ece10f6243d719ba28173b69bd99110a
This reverts commit 9b5950db86.
Waste can be negative. At feerates lower than long_term_feerate this
means that a waste of 0 may be a suboptimal solution and this causes the
search to exit prematurely.
Only when the feerate is equal to the long_term_feerate would achieving
a waste of 0 indicate that we have achieved an optimal solution,
because it would mean that the excess is 0. It seems unlikely
that this would ever occur outside of test cases, and even then we
should prefer solutions with more inputs over solutions with fewer
according to previous decisions—but solutions with more inputs are found
later in the branch exploration.
The "optimization" described in #18257 and implemented in #18262 is
therefore a premature exit on a suboptimal solution and should be reverted.
Previously in COutput, effective_value was initialized as the absolute
value of the txout, and fee as 0. effective_value along with fee were
calculated outside of the COutput constructor and set after the
object had been initialized. These changes will allow either the fee
or the feerate to be passed in a COutput constructor. If either are
provided, fee and effective_value are calculated and set in the
constructor. As a result, AvailableCoins also needs to be passed the
feerate when utxos are being spent. When balance is calculated or the
coins are being listed and feerate is neither available nor required,
AvailableCoinsListUnspent is used instead, which runs AvailableCoins
while providing the default value for feerate. Unit tests for the
calculation of effective value have also been added.
3f8def51d5 add 3 new test cases for SelectCoins() (akankshakashyap)
Pull request description:
Three new tests have been added.
1. More coins should be selected when effective fee < long term fee.
2. Less coin should be selected when effective fee > long term fee.
3. If a coin is preselected, it should be selected even if disadvantageous.
ACKs for top commit:
achow101:
ACK 3f8def51d5
brunoerg:
ACK 3f8def51d5
Tree-SHA512: 8db6dd942b02a38c99953b801605f98c4c17729768fdfcf7605c5bbdb17509500a39d0a78a4b19aab37812d2994ec7630d2b4e78d1d348f1c27b67588d74e155
1. More coins should be selected when effective fee < long term fee.
2. Less coin should be selected when effective fee > long term fee.
3. If a coin is preselected, it should be selected even if disadvantageous.
049003fe68 coinselection: Remove COutput operators == and != (Andrew Chow)
f6c39c6adb coinselection: Remove CInputCoin (Andrew Chow)
70f31f1a81 coinselection: Use COutput instead of CInputCoin (Andrew Chow)
14fbb57b79 coinselection: Add effective value and fees to COutput (Andrew Chow)
f0821230b8 moveonly: move COutput to coinselection.h (Andrew Chow)
42e974e15c wallet: Remove CWallet and CWalletTx from COutput's constructor (Andrew Chow)
14d04d5ad1 wallet: Replace CWalletTx in COutput with COutPoint and CTxOut (Andrew Chow)
0ba4d1916e wallet: Provide input bytes to COutput (Andrew Chow)
d51f27d3bb wallet: Store whether a COutput is from the wallet (Andrew Chow)
b799814bbd wallet: Store tx time in COutput (Andrew Chow)
46022953ee wallet: Remove use_max_sig default value (Andrew Chow)
10379f007f scripted-diff: Rename COutput member variables (Andrew Chow)
c7c64db41e wallet: cleanup COutput constructor (Andrew Chow)
Pull request description:
While working on coin selection code, it occurred to me that `CInputCoin` is really a subset of `COutput` and the conversion of a `COutput` to a `CInputCoin` does not appear to be all that useful. So this PR adds fields that are present in `CInputCoin` to `COutput` and replaces the usage of `CInputCoin` with `COutput`.
`COutput` is also moved to coinselection.h. As part of this move, the usage of `CWalletTx` is removed from `COutput`. It is instead replaced by storing a `COutPoint` and the `CTxOut` rather than the entire `CWalletTx` as coin selection does not really need the full `CWalletTx`. The `CWalletTx` was only used for figuring out whether the transaction containing the output was from the current wallet, and for the transaction's time. These are now parameters to `COutput`'s constructor.
ACKs for top commit:
ryanofsky:
Code review ACK 049003fe68, just adding comments and removing == operators since last review
w0xlt:
reACK 049003f
Xekyo:
reACK 049003fe68
Tree-SHA512: 048b4cd620a0415e1d9fe8597257ee4bc64656566e1d28a9bdd147d6d72dc87c3f34a3339fa9ab6acf42c388df7901fc4ee900ccaabc3de790ffad162b544c15
These operators are used only by the tests in std::mismatch. As
std::mismatch can take a binary predicate, we can use a lambda that
achieves the same instead.
Instead of having a pointer to the CWalletTx in COutput, we can just
store the COutPoint and the CTxOut as those are the only things we need
from the CWalletTx. Other things CWalletTx used to provide were time and
fIsFromMe but these are also being stored by COutput.
Instead of determining whether the containing transaction is from the
wallet dynamically as needed, just pass it in to COutput and store it.
The transaction ownership isn't going to change.
05300c1439 Use SelectionResult in SelectCoins (Andrew Chow)
9d9b101d20 Use SelectionResult in AttemptSelection (Andrew Chow)
bb50850a44 Use SelectionResult for waste calculation (Andrew Chow)
e8f7ae5eb3 Make an OutputGroup for preset inputs (Andrew Chow)
51a9c00b4d Return SelectionResult from SelectCoinsSRD (Andrew Chow)
0ef6184575 Return SelectionResult from KnapsackSolver (Andrew Chow)
60d2ca72e3 Return SelectionResult from SelectCoinsBnB (Andrew Chow)
a339add471 Make member variables of SelectionResult private (Andrew Chow)
cbf0b9f4ff scripted-diff: Use SelectionResult in coin selector tests (Andrew Chow)
9d1d86da04 Introduce SelectionResult struct (Andrew Chow)
94d851d28c Fix bnb_search_test to use set equivalence for (Andrew Chow)
Pull request description:
Instead of returning a set of selected coins and their total value as separate items, encapsulate both of these, and other variables, into a new `SelectionResult` struct. This allows us to have all of the things relevant to a coin selection solution be in a single object. `SelectionResult` enables us to implement the waste calculation in a cleaner way.
All of the coin selection functions (`SelectCoinsBnB`, `KnapsackSolver`, `AttemptSelection`, and `SelectCoins`) are changed to use a `SelectionResult` as the output parameter.
Based on #22009
ACKs for top commit:
laanwj:
Code review ACK 05300c1439
Tree-SHA512: e4dbb4d78a6cda9c237d230b19e7265591efac5a101a64e6970f0654e2c4f93d13bb5d07b98e8c7b8d37321753dbfc94c28c3a7810cb1c59b5bc29b08a8493ef
Replace the CoinSet actual_selection with a SelectionResult
expected_result. We don't use the SelectionResult functions yet, but
will soon.
-BEGIN VERIFY SCRIPT-
sed -i 's/CoinSet actual_selection/SelectionResult expected_result(CAmount(0))/' src/wallet/test/coinselector_tests.cpp
sed -i 's/actual_selection/expected_result.m_selected_inputs/' src/wallet/test/coinselector_tests.cpp
sed -i 's/expected_result.m_selected_inputs.clear/expected_result.Clear/' src/wallet/test/coinselector_tests.cpp
-END VERIFY SCRIPT-
fa00447442 scripted-diff: Use clang-tidy syntax for C++ named arguments (MarcoFalke)
fae13c3989 doc: Use clang-tidy comments in crypto_tests (MarcoFalke)
Pull request description:
Incorrect named args are source of bugs, like #22979.
To allow them being checked by `clang-tidy`, use a format it can understand.
ACKs for top commit:
shaavan:
ACK fa00447442
rajarshimaitra:
ACK fa00447442
jonatack:
ACK fa00447442
fanquake:
ACK fa00447442
Tree-SHA512: 4d23a8363da81dfea21a4cd8516ab5e0dc70119e4d503f3f240f38573218b2c2e84083b97e956c62942d78b2f17490f8b3b2e8077d257644fda1d901e2b80507
Current CWalletTx state representation makes it possible to set
inconsistent states that won't be handled correctly by wallet sync code
or serialized & deserialized back into the same form.
For example, it is possible to call setConflicted without setting a
conflicting block hash, or setConfirmed with no transaction index. And
it's possible update individual m_confirm and fInMempool data fields
without setting an overall consistent state that can be serialized and
handled correctly.
Fix this without changing behavior by using std::variant, instead of an
enum and collection of fields, to represent sync state, so state
tracking code is safer and more legible.
This is a first step to fixing state tracking bugs
https://github.com/bitcoin-core/bitcoin-devwiki/wiki/Wallet-Transaction-Conflict-Tracking,
by adding an extra margin of safety that can prevent new bugs from being
introduced as existing bugs are fixed.
Instead of using AddToWallet so that making a COutput will work,
directly add the transaction into wallet.mapWallet. This bypasses many
checks that AddToWallet will do which are pointless and just slow down
this test.
To avoid issues with test data leaking across tests cases, the global
vCoins and testWallet are removed from coinselector_tests and all of the
relevant functions reworked to not need them.
There are two more cases where waste can be 0, when:
- (Fee - LTF) == -Change Cost
- (Fee - LTF) == -Excess
Adding these two conditions explicitly in the unit test will help
pin the behavior, also demonstrate waste calculation scenarios to new
readers.
Followup to commit "MOVEONLY: CWallet transaction code out of
wallet.cpp/.h" that detaches and renames some CWalletTx methods, making
into them into standalone functions or CWallet methods instead.
There are no changes in behavior and no code changes that aren't purely
mechanical. It just gives spend and receive functions more consistent
names and removes the circular dependencies added by the earlier
MOVEONLY commit.
There are also no comment or documentation changes. Removed comments
from transaction.h are just migrated to spend.h, receive.h, and
wallet.h.
