Use REJECT_DUPLICATE for already known and conflicted txn

src/validation.cpp

@@ -427,8 +427,9 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
         return state.DoS(0, false, REJECT_NONSTANDARD, "non-final");
 
     // is it already in the memory pool?
-    if (pool.exists(hash))
+    if (pool.exists(hash)) {
-        return state.Invalid(false, REJECT_ALREADY_KNOWN, "txn-already-in-mempool");
+        return state.Invalid(false, REJECT_DUPLICATE, "txn-already-in-mempool");
+    }
 
     // Check for conflicts with in-memory transactions
     std::set<uint256> setConflicts;
@@ -466,8 +467,9 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
                         }
                     }
                 }
-                if (fReplacementOptOut)
+                if (fReplacementOptOut) {
-                    return state.Invalid(false, REJECT_CONFLICT, "txn-mempool-conflict");
+                    return state.Invalid(false, REJECT_DUPLICATE, "txn-mempool-conflict");
+                }
 
                 setConflicts.insert(ptxConflicting->GetHash());
             }
@@ -494,7 +496,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
                 if (!had_coin_in_cache) {
                     coins_to_uncache.push_back(outpoint);
                 }
-                return state.Invalid(false, REJECT_ALREADY_KNOWN, "txn-already-known");
+                return state.Invalid(false, REJECT_DUPLICATE, "txn-already-known");
             }
         }
 

src/validation.h

@@ -509,10 +509,6 @@ int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Para
 static const unsigned int REJECT_INTERNAL = 0x100;
 /** Too high fee. Can not be triggered by P2P transactions */
 static const unsigned int REJECT_HIGHFEE = 0x100;
-/** Transaction is already known (either in mempool or blockchain) */
-static const unsigned int REJECT_ALREADY_KNOWN = 0x101;
-/** Transaction conflicts with a transaction already known */
-static const unsigned int REJECT_CONFLICT = 0x102;
 
 /** Get block file info entry for one block file */
 CBlockFileInfo* GetBlockFileInfo(size_t n);