Revert "Get rid of consensus.fPowAllowMinDifficultyBlocks."

This reverts commit dffc025d38.

src/chainparams.cpp

@@ -95,6 +95,7 @@ public:
         consensus.nPowMaxAdjustDown = 32; // 32% adjustment down
         consensus.nPowMaxAdjustUp = 16; // 16% adjustment up
         consensus.nPowTargetSpacing = 2.5 * 60;
+        consensus.fPowAllowMinDifficultyBlocks = false;
         consensus.vUpgrades[Consensus::BASE_SPROUT].nProtocolVersion = 170002;
         consensus.vUpgrades[Consensus::BASE_SPROUT].nActivationHeight =
             Consensus::NetworkUpgrade::ALWAYS_ACTIVE;
@@ -271,6 +272,7 @@ public:
         consensus.nPowMaxAdjustDown = 32; // 32% adjustment down
         consensus.nPowMaxAdjustUp = 16; // 16% adjustment up
         consensus.nPowTargetSpacing = 2.5 * 60;
+        consensus.fPowAllowMinDifficultyBlocks = true;
         consensus.vUpgrades[Consensus::BASE_SPROUT].nProtocolVersion = 170002;
         consensus.vUpgrades[Consensus::BASE_SPROUT].nActivationHeight =
             Consensus::NetworkUpgrade::ALWAYS_ACTIVE;
@@ -391,6 +393,7 @@ public:
         consensus.nPowMaxAdjustDown = 0; // Turn off adjustment down
         consensus.nPowMaxAdjustUp = 0; // Turn off adjustment up
         consensus.nPowTargetSpacing = 2.5 * 60;
+        consensus.fPowAllowMinDifficultyBlocks = true;
         consensus.vUpgrades[Consensus::BASE_SPROUT].nProtocolVersion = 170002;
         consensus.vUpgrades[Consensus::BASE_SPROUT].nActivationHeight =
             Consensus::NetworkUpgrade::ALWAYS_ACTIVE;

src/consensus/params.h

@@ -91,6 +91,7 @@ struct Params {
     NetworkUpgrade vUpgrades[MAX_NETWORK_UPGRADES];
     /** Proof of work parameters */
     uint256 powLimit;
+    bool fPowAllowMinDifficultyBlocks;
     int64_t nPowAveragingWindow;
     int64_t nPowMaxAdjustDown;
     int64_t nPowMaxAdjustUp;

src/miner.cpp

@@ -101,6 +101,10 @@ public:
 void UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
 {
     pblock->nTime = std::max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
+
+    // Updating time can change work required on testnet:
+    if (consensusParams.fPowAllowMinDifficultyBlocks)
+        pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, consensusParams);
 }
 
 CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn)
@@ -722,6 +726,11 @@ void static BitcoinMiner()
                 // Update nNonce and nTime
                 pblock->nNonce = ArithToUint256(UintToArith256(pblock->nNonce) + 1);
                 UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev);
+                if (chainparams.GetConsensus().fPowAllowMinDifficultyBlocks)
+                {
+                    // Changing pblock->nTime can change work required on testnet:
+                    hashTarget.SetCompact(pblock->nBits);
+                }
             }
         }
     }