Merge bitcoin/bitcoin#25685: wallet: Faster transaction creation by removing pre-set-inputs fetching responsibility from Coin Selection

3fcb545ab26be3e785b5e5654be0bdc77099d827 bench: benchmark transaction creation process (furszy)
a8a75346d7e7247596c8a580d65ceaad49c97b97 wallet: SelectCoins, return early if target is covered by preset-inputs (furszy)
f41712a734dc119f8a5e053a9cfa1f0411b5e8f1 wallet: simplify preset inputs selection target check (furszy)
5baedc33519661af9d19efcefd23dca8998d2547 wallet: remove fetch pre-selected-inputs responsibility from SelectCoins (furszy)
295852f61998a025b0b28a0671e6e1cf0dc08d0d wallet: encapsulate pre-selected-inputs lookup into its own function (furszy)
37e7887cb4bfd7db6eb462ed0741c45aea22a990 wallet: skip manually selected coins from 'AvailableCoins' result (furszy)
94c0766b0cd1990c1399a745c88c2ba4c685d8d1 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 3fcb545ab26be3e785b5e5654be0bdc77099d827
  achow101:
    ACK 3fcb545ab26be3e785b5e5654be0bdc77099d827
  aureleoules:
    reACK 3fcb545ab26be3e785b5e5654be0bdc77099d827

Tree-SHA512: 42f833e92f40c348007ca565a4c98039e6f1ff25d8322bc2b27115824744779baf0b0a38452e4e2cdcba45076473f1028079bbd0f670020481ec5d3db42e4731

1 files changed, 3 insertions, 1 deletions

diff --git a/src/qt/sendcoinsdialog.cpp b/src/qt/sendcoinsdialog.cpp
index 53c352b393..57094fc857 100644
--- a/src/qt/sendcoinsdialog.cpp
+++ b/src/qt/sendcoinsdialog.cpp
@@ -289,7 +289,9 @@ bool SendCoinsDialog::PrepareSendText(QString& question_string, QString& informa
 
     updateCoinControlState();
 
-    prepareStatus = model->prepareTransaction(*m_current_transaction, *m_coin_control);
+    CCoinControl coin_control = *m_coin_control;
+    coin_control.m_allow_other_inputs = !coin_control.HasSelected(); // future, could introduce a checkbox to customize this value.
+    prepareStatus = model->prepareTransaction(*m_current_transaction, coin_control);
 
     // process prepareStatus and on error generate message shown to user
     processSendCoinsReturn(prepareStatus,