Merge #11413: [wallet] [rpc] sendtoaddress/sendmany: Add explicit feerate option

25dac9f doc: add release notes for explicit fee estimators and bumpfee change (Karl-Johan Alm)
05227a3 tests for bumpfee / estimate_modes (Karl-Johan Alm)
3404c1b policy: optional FeeEstimateMode param to CFeeRate::ToString (Karl-Johan Alm)
6fcf448 rpc/wallet: add two explicit modes to estimate_mode (Karl-Johan Alm)
b188d80 MOVEONLY: Make FeeEstimateMode available to CFeeRate (Karl-Johan Alm)
5d1a411 fees: add FeeModes doc helper function (Karl-Johan Alm)
91f6d2b rpc/wallet: add conf_target as alias to confTarget in bumpfee (Karl-Johan Alm)
69158b4 added CURRENCY_ATOM to express minimum indivisible unit (Karl-Johan Alm)

Pull request description:

  This lets users pick their own fees when using `sendtoaddress`/`sendmany` if they prefer this over the estimators.

ACKs for top commit:
  Sjors:
    re-utACK 25dac9f: rebased, more fancy C++,
  jonatack:
    ACK 25dac9f I think this should be merged after all this time, even though it looks to me like there are needed follow-ups, fixes and test coverage to be added (see further down), which I don't mind helping out with, if wanted.
  fjahr:
    Code review ACK 25dac9f

Tree-SHA512: f31177e6cabf3187a43cdfe93477144f8e8385c7344613743cbbd16e8490d53ff5144aec7b9de6c9a65eb855b55e0f99d7f164dee4b6bf3cfea4dce51cf11d33

Author: laanwj

doc/release-notes-11413.md

@@ -0,0 +1,11 @@
+Updated or changed RPC
+----------------------
+
+The `bumpfee`, `fundrawtransaction`, `sendmany`, `sendtoaddress`, and `walletcreatefundedpsbt`
+RPC commands have been updated to include two new fee estimation methods "BTC/kB" and "sat/B".
+The target is the fee expressed explicitly in the given form. Note that use of this feature
+will trigger BIP 125 (replace-by-fee) opt-in.
+
+In addition, the `estimate_mode` parameter is now case insensitive for all of the above RPC commands.
+
+The `bumpfee` command now uses `conf_target` rather than `confTarget` in the options.

src/policy/feerate.cpp

@@ -7,8 +7,6 @@
 
 #include <tinyformat.h>
 
-const std::string CURRENCY_UNIT = "BTC";
-
 CFeeRate::CFeeRate(const CAmount& nFeePaid, size_t nBytes_)
 {
     assert(nBytes_ <= uint64_t(std::numeric_limits<int64_t>::max()));
@@ -37,7 +35,10 @@ CAmount CFeeRate::GetFee(size_t nBytes_) const
     return nFee;
 }
 
-std::string CFeeRate::ToString() const
+std::string CFeeRate::ToString(const FeeEstimateMode& fee_estimate_mode) const
 {
-    return strprintf("%d.%08d %s/kB", nSatoshisPerK / COIN, nSatoshisPerK % COIN, CURRENCY_UNIT);
+    switch (fee_estimate_mode) {
+    case FeeEstimateMode::SAT_B:  return strprintf("%d.%03d %s/B", nSatoshisPerK / 1000, nSatoshisPerK % 1000, CURRENCY_ATOM);
+    default:                      return strprintf("%d.%08d %s/kB", nSatoshisPerK / COIN, nSatoshisPerK % COIN, CURRENCY_UNIT);
+    }
 }

src/policy/feerate.h

@@ -11,7 +11,17 @@
 
 #include <string>
 
-extern const std::string CURRENCY_UNIT;
+const std::string CURRENCY_UNIT = "BTC"; // One formatted unit
+const std::string CURRENCY_ATOM = "sat"; // One indivisible minimum value unit
+
+/* Used to determine type of fee estimation requested */
+enum class FeeEstimateMode {
+    UNSET,        //!< Use default settings based on other criteria
+    ECONOMICAL,   //!< Force estimateSmartFee to use non-conservative estimates
+    CONSERVATIVE, //!< Force estimateSmartFee to use conservative estimates
+    BTC_KB,       //!< Use explicit BTC/kB fee given in coin control
+    SAT_B,        //!< Use explicit sat/B fee given in coin control
+};
 
 /**
  * Fee rate in satoshis per kilobyte: CAmount / kB
@@ -46,7 +56,7 @@ class CFeeRate
     friend bool operator>=(const CFeeRate& a, const CFeeRate& b) { return a.nSatoshisPerK >= b.nSatoshisPerK; }
     friend bool operator!=(const CFeeRate& a, const CFeeRate& b) { return a.nSatoshisPerK != b.nSatoshisPerK; }
     CFeeRate& operator+=(const CFeeRate& a) { nSatoshisPerK += a.nSatoshisPerK; return *this; }
-    std::string ToString() const;
+    std::string ToString(const FeeEstimateMode& fee_estimate_mode = FeeEstimateMode::BTC_KB) const;
 
     SERIALIZE_METHODS(CFeeRate, obj) { READWRITE(obj.nSatoshisPerK); }
 };

src/policy/fees.h

@@ -45,13 +45,6 @@ enum class FeeReason {
     REQUIRED,
 };
 
-/* Used to determine type of fee estimation requested */
-enum class FeeEstimateMode {
-    UNSET,        //!< Use default settings based on other criteria
-    ECONOMICAL,   //!< Force estimateSmartFee to use non-conservative estimates
-    CONSERVATIVE, //!< Force estimateSmartFee to use conservative estimates
-};
-
 /* Used to return detailed information about a feerate bucket */
 struct EstimatorBucket
 {

src/util/fees.cpp

@@ -6,11 +6,16 @@
 #include <util/fees.h>
 
 #include <policy/fees.h>
+#include <util/strencodings.h>
+#include <util/string.h>
 
 #include <map>
 #include <string>
+#include <vector>
+#include <utility>
 
-std::string StringForFeeReason(FeeReason reason) {
+std::string StringForFeeReason(FeeReason reason)
+{
     static const std::map<FeeReason, std::string> fee_reason_strings = {
         {FeeReason::NONE, "None"},
         {FeeReason::HALF_ESTIMATE, "Half Target 60% Threshold"},
@@ -29,16 +34,31 @@ std::string StringForFeeReason(FeeReason reason) {
     return reason_string->second;
 }
 
-bool FeeModeFromString(const std::string& mode_string, FeeEstimateMode& fee_estimate_mode) {
-    static const std::map<std::string, FeeEstimateMode> fee_modes = {
-        {"UNSET", FeeEstimateMode::UNSET},
-        {"ECONOMICAL", FeeEstimateMode::ECONOMICAL},
-        {"CONSERVATIVE", FeeEstimateMode::CONSERVATIVE},
+const std::vector<std::pair<std::string, FeeEstimateMode>>& FeeModeMap()
+{
+    static const std::vector<std::pair<std::string, FeeEstimateMode>> FEE_MODES = {
+        {"unset", FeeEstimateMode::UNSET},
+        {"economical", FeeEstimateMode::ECONOMICAL},
+        {"conservative", FeeEstimateMode::CONSERVATIVE},
+        {(CURRENCY_UNIT + "/kB"), FeeEstimateMode::BTC_KB},
+        {(CURRENCY_ATOM + "/B"), FeeEstimateMode::SAT_B},
     };
-    auto mode = fee_modes.find(mode_string);
+    return FEE_MODES;
+}
 
-    if (mode == fee_modes.end()) return false;
+std::string FeeModes(const std::string& delimiter)
+{
+    return Join(FeeModeMap(), delimiter, [&](const std::pair<std::string, FeeEstimateMode>& i) { return i.first; });
+}
 
-    fee_estimate_mode = mode->second;
-    return true;
+bool FeeModeFromString(const std::string& mode_string, FeeEstimateMode& fee_estimate_mode)
+{
+    auto searchkey = ToUpper(mode_string);
+    for (const auto& pair : FeeModeMap()) {
+        if (ToUpper(pair.first) == searchkey) {
+            fee_estimate_mode = pair.second;
+            return true;
+        }
+    }
+    return false;
 }

src/util/fees.h

@@ -12,5 +12,6 @@ enum class FeeReason;
 
 bool FeeModeFromString(const std::string& mode_string, FeeEstimateMode& fee_estimate_mode);
 std::string StringForFeeReason(FeeReason reason);
+std::string FeeModes(const std::string& delimiter);
 
 #endif // BITCOIN_UTIL_FEES_H