Merge pull request #2311 from rnicoll/1.21-subsidy-tests1.21-dev

Rewrite subsidy limit tests (1.21)

2 files changed, 17 insertions, 9 deletions

diff --git a/src/policy/feerate.cpp b/src/policy/feerate.cpp
index 04e0e117a..aeeb341ea 100644
--- a/src/policy/feerate.cpp
+++ b/src/policy/feerate.cpp
@@ -13,7 +13,8 @@ CFeeRate::CFeeRate(const CAmount& nFeePaid, size_t nBytes_)
     int64_t nSize = int64_t(nBytes_);
 
     if (nSize > 0)
-        nSatoshisPerK = nFeePaid * 1000 / nSize;
+        // Dogecoin: Cap the fee paid so we can't overflow.
+        nSatoshisPerK = std::min(MAX_FEE_RATE, nFeePaid) * 1000 / nSize;
     else
         nSatoshisPerK = 0;
 }
diff --git a/src/policy/feerate.h b/src/policy/feerate.h
index 0ef97f63b..18c669b45 100644
--- a/src/policy/feerate.h
+++ b/src/policy/feerate.h
@@ -14,6 +14,12 @@
 const std::string CURRENCY_UNIT = "DOGE"; // One formatted unit
 const std::string CURRENCY_ATOM = "koinu"; // One indivisible minimum value unit
 
+// Dogecoin: Bitcoin uses MAX_MONEY as the maximum fee rate, but that leads to
+// overflows with Doge MAX_MONEY, so instead we have it as a distinct value.
+static const CAmount MAX_FEE_RATE = 21000000 * COIN;
+
+inline bool FeeRange(const CAmount& nValue) { return (nValue >= 0 && nValue <= MAX_FEE_RATE); }
+
 /* Used to determine type of fee estimation requested */
 enum class FeeEstimateMode {
     UNSET,        //!< Use default settings based on other criteria
@@ -29,33 +35,34 @@ enum class FeeEstimateMode {
 class CFeeRate
 {
 private:
-    CAmount nSatoshisPerK; // unit is satoshis-per-1,000-bytes
+    CAmount nSatoshisPerK; // unit is Koinu-per-1,000-bytes
 
 public:
-    /** Fee rate of 0 satoshis per kB */
+    /** Fee rate of 0 Koinu per kB */
     CFeeRate() : nSatoshisPerK(0) { }
     template<typename I>
     explicit CFeeRate(const I _nSatoshisPerK): nSatoshisPerK(_nSatoshisPerK) {
         // We've previously had bugs creep in from silent double->int conversion...
         static_assert(std::is_integral<I>::value, "CFeeRate should be used without floats");
     }
-    /** Constructor for a fee rate in satoshis per kvB (sat/kvB). The size in bytes must not exceed (2^63 - 1).
+    /** Constructor for a fee rate in Koinu per kvB (Koinu/kvB). The fee paid should not exceed MAX_FEE_RATE, and
+     * size in bytes must not exceed (2^63 - 1).
      *
-     *  Passing an nBytes value of COIN (1e8) returns a fee rate in satoshis per vB (sat/vB),
+     *  Passing an nBytes value of COIN (1e8) returns a fee rate in Koinu per vB (Koinu/vB),
      *  e.g. (nFeePaid * 1e8 / 1e3) == (nFeePaid / 1e5),
-     *  where 1e5 is the ratio to convert from BTC/kvB to sat/vB.
+     *  where 1e5 is the ratio to convert from DOGE/kvB to Koinu/vB.
      *
-     *  @param[in] nFeePaid  CAmount fee rate to construct with
+     *  @param[in] nFeePaid  CAmount fee rate to construct with. If this exceeds MAX_FEE_RATE it will be capped at MAX_FEE_RATE.
      *  @param[in] nBytes    size_t bytes (units) to construct with
      *  @returns   fee rate
      */
     CFeeRate(const CAmount& nFeePaid, size_t nBytes);
     /**
-     * Return the fee in satoshis for the given size in bytes.
+     * Return the fee in Koinu for the given size in bytes.
      */
     CAmount GetFee(size_t nBytes) const;
     /**
-     * Return the fee in satoshis for a size of 1000 bytes
+     * Return the fee in Koinu for a size of 1000 bytes
      */
     CAmount GetFeePerK() const { return GetFee(1000); }
     friend bool operator<(const CFeeRate& a, const CFeeRate& b) { return a.nSatoshisPerK < b.nSatoshisPerK; }