Merge #19501: send* RPCs in the wallet returns the "fee reason"

69cf5d4eeb73f7d685e915fc17af64634d88a4a2 [test] Make sure send rpc returns fee reason (Sishir Giri)
d5863c0b3e20d56acf7246008b7832efde68ab21 [send] Make send RPCs return fee reason (Sishir Giri)

Pull request description:

  Whenever a wallet funds a transaction, the fee reason is reported to the user only if the verbose is set to true. I added an extra parameter to `CreateTransaction` function in wallet.cpp. Then I implemented the fee reason return logic in `SendMoney`  in rpcwallet.cpp, followed by verbose parameter in `sendtoaddress` and `sendmany` functions. I also added a fee reason test case in walletbasic.py.

  link to the issue: https://github.com/MarcoFalke/bitcoin-core/issues/22#issue-616251578

ACKs for top commit:
  instagibbs:
    ACK https://github.com/bitcoin/bitcoin/pull/19501/commits/69cf5d4eeb73f7d685e915fc17af64634d88a4a2
  meshcollider:
    utACK 69cf5d4eeb73f7d685e915fc17af64634d88a4a2

Tree-SHA512: 2e3af32dcfbd5511ba95f8bc8edca7acfe709a8430ff03e43172e5d0af3dfa4b2f57906978e7f272d878043b9ed8c6004674cf47d7496b005d5f612e9a58aa0e

1 files changed, 7 insertions, 3 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 6f320096eb..4d8c0b175b 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2629,7 +2629,8 @@ bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, int& nC
     LOCK(cs_wallet);
 
     CTransactionRef tx_new;
-    if (!CreateTransaction(vecSend, tx_new, nFeeRet, nChangePosInOut, error, coinControl, false)) {
+    FeeCalculation fee_calc_out;
+    if (!CreateTransaction(vecSend, tx_new, nFeeRet, nChangePosInOut, error, coinControl, fee_calc_out, false)) {
         return false;
     }
 
@@ -2753,6 +2754,7 @@ bool CWallet::CreateTransactionInternal(
         int& nChangePosInOut,
         bilingual_str& error,
         const CCoinControl& coin_control,
+        FeeCalculation& fee_calc_out,
         bool sign)
 {
     CAmount nValue = 0;
@@ -3096,6 +3098,7 @@ bool CWallet::CreateTransactionInternal(
     // Before we return success, we assume any change key will be used to prevent
     // accidental re-use.
     reservedest.KeepDestination();
+    fee_calc_out = feeCalc;
 
     WalletLogPrintf("Fee Calculation: Fee:%d Bytes:%u Needed:%d Tgt:%d (requested %d) Reason:\"%s\" Decay %.5f: Estimation: (%g - %g) %.2f%% %.1f/(%.1f %d mem %.1f out) Fail: (%g - %g) %.2f%% %.1f/(%.1f %d mem %.1f out)\n",
               nFeeRet, nBytes, nFeeNeeded, feeCalc.returnedTarget, feeCalc.desiredTarget, StringForFeeReason(feeCalc.reason), feeCalc.est.decay,
@@ -3115,11 +3118,12 @@ bool CWallet::CreateTransaction(
         int& nChangePosInOut,
         bilingual_str& error,
         const CCoinControl& coin_control,
+        FeeCalculation& fee_calc_out,
         bool sign)
 {
     int nChangePosIn = nChangePosInOut;
     CTransactionRef tx2 = tx;
-    bool res = CreateTransactionInternal(vecSend, tx, nFeeRet, nChangePosInOut, error, coin_control, sign);
+    bool res = CreateTransactionInternal(vecSend, tx, nFeeRet, nChangePosInOut, error, coin_control, fee_calc_out, sign);
     // try with avoidpartialspends unless it's enabled already
     if (res && nFeeRet > 0 /* 0 means non-functional fee rate estimation */ && m_max_aps_fee > -1 && !coin_control.m_avoid_partial_spends) {
         CCoinControl tmp_cc = coin_control;
@@ -3127,7 +3131,7 @@ bool CWallet::CreateTransaction(
         CAmount nFeeRet2;
         int nChangePosInOut2 = nChangePosIn;
         bilingual_str error2; // fired and forgotten; if an error occurs, we discard the results
-        if (CreateTransactionInternal(vecSend, tx2, nFeeRet2, nChangePosInOut2, error2, tmp_cc, sign)) {
+        if (CreateTransactionInternal(vecSend, tx2, nFeeRet2, nChangePosInOut2, error2, tmp_cc, fee_calc_out, sign)) {
             // if fee of this alternative one is within the range of the max fee, we use this one
             const bool use_aps = nFeeRet2 <= nFeeRet + m_max_aps_fee;
             WalletLogPrintf("Fee non-grouped = %lld, grouped = %lld, using %s\n", nFeeRet, nFeeRet2, use_aps ? "grouped" : "non-grouped");