Merge bitcoin#17519: rpc: Remove unused COINBASE_FLAGS

e9a27cf refactor: Remove unused COINBASE_FLAGS (Neha Narula)

Pull request description:

  Commit d449772 stopped setting
  COINBASE_FLAGS, and it looks like it hasn't been used since P2SH.

  Following up on bitcoin#17489, remove COINBASE_FLAGS which is unused. I verified that removing this did not change the contents of the coinbase's scriptSig.

ACKs for top commit:
  laanwj:
    ACK e9a27cf
  MarcoFalke:
    ACK e9a27cf 💻

Tree-SHA512: f9dac124ce7e3edcae974137764bb5039387b1b123b86af44486e398aa4a8d91a9ecf640e207b364ae303acbbaee7cca300d303ea3d6869ba9cae2bf555a6334

src/miner.cpp

@@ -502,7 +502,7 @@ void IncrementExtraNonce(CBlock* pblock, const CBlockIndex* pindexPrev, unsigned
     ++nExtraNonce;
     unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
     CMutableTransaction txCoinbase(*pblock->vtx[0]);
-    txCoinbase.vin[0].scriptSig = (CScript() << nHeight << CScriptNum(nExtraNonce)) + COINBASE_FLAGS;
+    txCoinbase.vin[0].scriptSig = (CScript() << nHeight << CScriptNum(nExtraNonce));
     assert(txCoinbase.vin[0].scriptSig.size() <= 100);
 
     pblock->vtx[0] = MakeTransactionRef(std::move(txCoinbase));

src/rpc/mining.cpp

@@ -349,10 +349,8 @@ static UniValue getblocktemplate(const JSONRPCRequest& request)
             "      }\n"
             "      ,...\n"
             "  ],\n"
-            "  \"coinbaseaux\" : {                 (json object) data that should be included in the coinbase's scriptSig content\n"
-            "      \"flags\" : \"xx\"                  (string) key name is to be ignored, and value included in scriptSig\n"
-            "  },\n"
-            "  \"coinbasevalue\" : n,              (numeric) maximum allowable input to coinbase transaction, including the generation award and transaction fees (in duffs)\n"
+            "  \"coinbaseaux\" : { ... },            (json object) data that should be included in the coinbase's scriptSig content\n"
+            "  \"coinbasevalue\" : n,              (numeric) maximum allowable input to coinbase transaction, including the generation award and transaction fees (in satoshis)\n"
             "  \"coinbasetxn\" : { ... },          (json object) information for coinbase transaction\n"
             "  \"target\" : \"xxxx\",                (string) The hash target\n"
             "  \"mintime\" : xxx,                  (numeric) The minimum timestamp appropriate for next block time in seconds since epoch (Jan 1 1970 GMT)\n"
@@ -591,7 +589,6 @@ static UniValue getblocktemplate(const JSONRPCRequest& request)
     }
 
     UniValue aux(UniValue::VOBJ);
-    aux.pushKV("flags", HexStr(COINBASE_FLAGS));
 
     arith_uint256 hashTarget = arith_uint256().SetCompact(pblock->nBits);
 

src/validation.cpp

@@ -281,9 +281,6 @@ std::atomic_bool g_is_mempool_loaded{false};
 
 static void CheckBlockIndex(const Consensus::Params& consensusParams);
 
-/** Constant stuff for coinbase transactions we create: */
-CScript COINBASE_FLAGS;
-
 // Internal stuff
 namespace {
     CBlockIndex *&pindexBestInvalid = g_chainstate.pindexBestInvalid;

src/validation.h

@@ -117,7 +117,6 @@ struct BlockHasher
     size_t operator()(const uint256& hash) const { return hash.GetCheapHash(); }
 };
 
-extern CScript COINBASE_FLAGS;
 extern CCriticalSection cs_main;
 extern CBlockPolicyEstimator feeEstimator;
 extern CTxMemPool mempool;