[Consensus] Bury segwit deployment

Hardcode segwit deployment height to 481824 for mainnet.

10 files changed, 38 insertions, 48 deletions

diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index 59c105817b..ad766471dc 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -70,6 +70,7 @@ public:
         consensus.BIP65Height = 388381; // 000000000000000004c2b624ed5d7756c508d90fd0da2c7c679febfa6c4735f0
         consensus.BIP66Height = 363725; // 00000000000000000379eaa19dce8c9b722d46ae6a57c2f1a988119488b50931
         consensus.CSVHeight = 419328; // 000000000000000004a1b34462cb8aeebd5799177f7a29cf28f2d1961716b5b5
+        consensus.SegwitHeight = 481824; // 0000000000000000001c8018d9cb3b742ef25114f27563e3fc4a1902167f9893
         consensus.powLimit = uint256S("00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff");
         consensus.nPowTargetTimespan = 14 * 24 * 60 * 60; // two weeks
         consensus.nPowTargetSpacing = 10 * 60;
@@ -81,11 +82,6 @@ public:
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 1199145601; // January 1, 2008
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = 1230767999; // December 31, 2008
 
-        // Deployment of SegWit (BIP141, BIP143, and BIP147)
-        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].bit = 1;
-        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nStartTime = 1479168000; // November 15th, 2016.
-        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout = 1510704000; // November 15th, 2017.
-
         // The best chain should have at least this much work.
         consensus.nMinimumChainWork = uint256S("0x0000000000000000000000000000000000000000051dc8b82f450202ecb3d471");
 
@@ -180,6 +176,7 @@ public:
         consensus.BIP65Height = 581885; // 00000000007f6655f22f98e72ed80d8b06dc761d5da09df0fa1dc4be4f861eb6
         consensus.BIP66Height = 330776; // 000000002104c8c45e99a8853285a3b592602a3ccde2b832481da85e9e4ba182
         consensus.CSVHeight = 770112; // 00000000025e930139bac5c6c31a403776da130831ab85be56578f3fa75369bb
+        consensus.SegwitHeight = 834624; // 00000000002b980fcd729daaa248fd9316a5200e9b367f4ff2c42453e84201ca
         consensus.powLimit = uint256S("00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff");
         consensus.nPowTargetTimespan = 14 * 24 * 60 * 60; // two weeks
         consensus.nPowTargetSpacing = 10 * 60;
@@ -191,11 +188,6 @@ public:
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 1199145601; // January 1, 2008
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = 1230767999; // December 31, 2008
 
-        // Deployment of SegWit (BIP141, BIP143, and BIP147)
-        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].bit = 1;
-        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nStartTime = 1462060800; // May 1st 2016
-        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout = 1493596800; // May 1st 2017
-
         // The best chain should have at least this much work.
         consensus.nMinimumChainWork = uint256S("0x00000000000000000000000000000000000000000000007dbe94253893cbd463");
 
@@ -268,6 +260,7 @@ public:
         consensus.BIP65Height = 1351; // BIP65 activated on regtest (Used in functional tests)
         consensus.BIP66Height = 1251; // BIP66 activated on regtest (Used in functional tests)
         consensus.CSVHeight = 432; // CSV activated on regtest (Used in rpc activation tests)
+        consensus.SegwitHeight = 0; // SEGWIT is always activated on regtest unless overridden
         consensus.powLimit = uint256S("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff");
         consensus.nPowTargetTimespan = 14 * 24 * 60 * 60; // two weeks
         consensus.nPowTargetSpacing = 10 * 60;
@@ -278,9 +271,6 @@ public:
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 0;
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
-        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].bit = 1;
-        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nStartTime = Consensus::BIP9Deployment::ALWAYS_ACTIVE;
-        consensus.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
 
         // The best chain should have at least this much work.
         consensus.nMinimumChainWork = uint256S("0x00");
@@ -297,7 +287,7 @@ public:
         m_assumed_blockchain_size = 0;
         m_assumed_chain_state_size = 0;
 
-        UpdateVersionBitsParametersFromArgs(args);
+        UpdateActivationParametersFromArgs(args);
 
         genesis = CreateGenesisBlock(1296688602, 2, 0x207fffff, 1, 50 * COIN);
         consensus.hashGenesisBlock = genesis.GetHash();
@@ -340,11 +330,22 @@ public:
         consensus.vDeployments[d].nStartTime = nStartTime;
         consensus.vDeployments[d].nTimeout = nTimeout;
     }
-    void UpdateVersionBitsParametersFromArgs(const ArgsManager& args);
+    void UpdateActivationParametersFromArgs(const ArgsManager& args);
 };
 
-void CRegTestParams::UpdateVersionBitsParametersFromArgs(const ArgsManager& args)
+void CRegTestParams::UpdateActivationParametersFromArgs(const ArgsManager& args)
 {
+    if (gArgs.IsArgSet("-segwitheight")) {
+        int64_t height = gArgs.GetArg("-segwitheight", consensus.SegwitHeight);
+        if (height < -1 || height >= std::numeric_limits<int>::max()) {
+            throw std::runtime_error(strprintf("Activation height %ld for segwit is out of valid range. Use -1 to disable segwit.", height));
+        } else if (height == -1) {
+            LogPrintf("Segwit disabled for testing\n");
+            height = std::numeric_limits<int>::max();
+        }
+        consensus.SegwitHeight = static_cast<int>(height);
+    }
+
     if (!args.IsArgSet("-vbparams")) return;
 
     for (const std::string& strDeployment : args.GetArgs("-vbparams")) {
diff --git a/src/chainparamsbase.cpp b/src/chainparamsbase.cpp
index deb8e0fb57..9b98dff3ca 100644
--- a/src/chainparamsbase.cpp
+++ b/src/chainparamsbase.cpp
@@ -19,6 +19,7 @@ void SetupChainParamsBaseOptions()
 {
     gArgs.AddArg("-regtest", "Enter regression test mode, which uses a special chain in which blocks can be solved instantly. "
                                    "This is intended for regression testing tools and app development.", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
+    gArgs.AddArg("-segwitheight=<n>", "Set the activation height of segwit. -1 to disable. (regtest-only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
     gArgs.AddArg("-testnet", "Use the test chain", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-vbparams=deployment:start:end", "Use given start/end times for specified version bits deployment (regtest-only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
 }
diff --git a/src/consensus/params.h b/src/consensus/params.h
index 69881ffdf2..8263b0fef4 100644
--- a/src/consensus/params.h
+++ b/src/consensus/params.h
@@ -16,7 +16,6 @@ namespace Consensus {
 enum DeploymentPos
 {
     DEPLOYMENT_TESTDUMMY,
-    DEPLOYMENT_SEGWIT, // Deployment of BIP141, BIP143, and BIP147.
     // NOTE: Also add new deployments to VersionBitsDeploymentInfo in versionbits.cpp
     MAX_VERSION_BITS_DEPLOYMENTS
 };
@@ -59,6 +58,10 @@ struct Params {
     int BIP66Height;
     /** Block height at which CSV (BIP68, BIP112 and BIP113) becomes active */
     int CSVHeight;
+    /** Block height at which Segwit (BIP141, BIP143 and BIP147) becomes active.
+     * Note that segwit v0 script rules are enforced on all blocks except the
+     * BIP 16 exception blocks. */
+    int SegwitHeight;
     /**
      * Minimum blocks including miner confirmation of the total of 2016 blocks in a retargeting period,
      * (nPowTargetTimespan / nPowTargetSpacing) which is also used for BIP9 deployments.
diff --git a/src/init.cpp b/src/init.cpp
index bb3ff8d88f..ab48dd4200 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1670,12 +1670,9 @@ bool AppInitMain(InitInterfaces& interfaces)
         }
     }
 
-    if (chainparams.GetConsensus().vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout != 0) {
-        // Only advertise witness capabilities if they have a reasonable start time.
-        // This allows us to have the code merged without a defined softfork, by setting its
-        // end time to 0.
-        // Note that setting NODE_WITNESS is never required: the only downside from not
-        // doing so is that after activation, no upgraded nodes will fetch from you.
+    if (chainparams.GetConsensus().SegwitHeight != std::numeric_limits<int>::max()) {
+        // Advertise witness capabilities.
+        // The option to not set NODE_WITNESS is only used in the tests and should be removed.
         nLocalServices = ServiceFlags(nLocalServices | NODE_WITNESS);
     }
 
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 808324afea..cd98b6c1bc 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1338,7 +1338,7 @@ UniValue getblockchaininfo(const JSONRPCRequest& request)
     BuriedForkDescPushBack(softforks, "bip66", consensusParams.BIP66Height);
     BuriedForkDescPushBack(softforks, "bip65", consensusParams.BIP65Height);
     BuriedForkDescPushBack(softforks, "csv", consensusParams.CSVHeight);
-    BIP9SoftForkDescPushBack(softforks, "segwit", consensusParams, Consensus::DEPLOYMENT_SEGWIT);
+    BuriedForkDescPushBack(softforks, "segwit", consensusParams.SegwitHeight);
     BIP9SoftForkDescPushBack(softforks, "testdummy", consensusParams, Consensus::DEPLOYMENT_TESTDUMMY);
     obj.pushKV("softforks",             softforks);
 
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index 48bc88823a..13bf611d32 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -482,9 +482,8 @@ static UniValue getblocktemplate(const JSONRPCRequest& request)
         // TODO: Maybe recheck connections/IBD and (if something wrong) send an expires-immediately template to stop miners?
     }
 
-    const struct VBDeploymentInfo& segwit_info = VersionBitsDeploymentInfo[Consensus::DEPLOYMENT_SEGWIT];
     // GBT must be called with 'segwit' set in the rules
-    if (setClientRules.count(segwit_info.name) != 1) {
+    if (setClientRules.count("segwit") != 1) {
         throw JSONRPCError(RPC_INVALID_PARAMETER, "getblocktemplate must be called with the segwit rule set (call with {\"rules\": [\"segwit\"]})");
     }
 
@@ -521,7 +520,7 @@ static UniValue getblocktemplate(const JSONRPCRequest& request)
     pblock->nNonce = 0;
 
     // NOTE: If at some point we support pre-segwit miners post-segwit-activation, this needs to take segwit support into consideration
-    const bool fPreSegWit = (ThresholdState::ACTIVE != VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT, versionbitscache));
+    const bool fPreSegWit = (pindexPrev->nHeight + 1 < consensusParams.SegwitHeight);
 
     UniValue aCaps(UniValue::VARR); aCaps.push_back("proposal");
 
diff --git a/src/test/setup_common.cpp b/src/test/setup_common.cpp
index de877fd167..4d928264b7 100644
--- a/src/test/setup_common.cpp
+++ b/src/test/setup_common.cpp
@@ -122,7 +122,7 @@ TestChain100Setup::TestChain100Setup() : TestingSetup(CBaseChainParams::REGTEST)
 {
     // CreateAndProcessBlock() does not support building SegWit blocks, so don't activate in these tests.
     // TODO: fix the code to support SegWit blocks.
-    gArgs.ForceSetArg("-vbparams", strprintf("segwit:0:%d", (int64_t)Consensus::BIP9Deployment::NO_TIMEOUT));
+    gArgs.ForceSetArg("-segwitheight", "432");
     SelectParams(CBaseChainParams::REGTEST);
 
     // Generate a 100-block chain:
diff --git a/src/validation.cpp b/src/validation.cpp
index fc15b755a7..ab45ec86e8 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1608,7 +1608,7 @@ static ThresholdConditionCache warningcache[VERSIONBITS_NUM_BITS] GUARDED_BY(cs_
 // environment. See test/functional/p2p-segwit.py.
 static bool IsScriptWitnessEnabled(const Consensus::Params& params)
 {
-    return params.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout != 0;
+    return params.SegwitHeight != std::numeric_limits<int>::max();
 }
 
 static unsigned int GetBlockScriptFlags(const CBlockIndex* pindex, const Consensus::Params& consensusparams) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
@@ -1649,7 +1649,8 @@ static unsigned int GetBlockScriptFlags(const CBlockIndex* pindex, const Consens
         flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
     }
 
-    if (IsNullDummyEnabled(pindex->pprev, consensusparams)) {
+    // Start enforcing BIP147 NULLDUMMY (activated simultaneously with segwit)
+    if (IsWitnessEnabled(pindex->pprev, consensusparams)) {
         flags |= SCRIPT_VERIFY_NULLDUMMY;
     }
 
@@ -3045,14 +3046,8 @@ bool CheckBlock(const CBlock& block, CValidationState& state, const Consensus::P
 
 bool IsWitnessEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
 {
-    LOCK(cs_main);
-    return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == ThresholdState::ACTIVE);
-}
-
-bool IsNullDummyEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
-{
-    LOCK(cs_main);
-    return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == ThresholdState::ACTIVE);
+    int height = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1;
+    return (height >= params.SegwitHeight);
 }
 
 // Compute at which vout of the block's coinbase transaction the witness
@@ -3087,7 +3082,7 @@ std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBloc
     std::vector<unsigned char> commitment;
     int commitpos = GetWitnessCommitmentIndex(block);
     std::vector<unsigned char> ret(32, 0x00);
-    if (consensusParams.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout != 0) {
+    if (consensusParams.SegwitHeight != std::numeric_limits<int>::max()) {
         if (commitpos == -1) {
             uint256 witnessroot = BlockWitnessMerkleRoot(block, nullptr);
             CHash256().Write(witnessroot.begin(), 32).Write(ret.data(), 32).Finalize(witnessroot.begin());
@@ -3222,7 +3217,7 @@ static bool ContextualCheckBlock(const CBlock& block, CValidationState& state, c
     //   {0xaa, 0x21, 0xa9, 0xed}, and the following 32 bytes are SHA256^2(witness root, witness reserved value). In case there are
     //   multiple, the last one is used.
     bool fHaveWitness = false;
-    if (VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == ThresholdState::ACTIVE) {
+    if (nHeight >= consensusParams.SegwitHeight) {
         int commitpos = GetWitnessCommitmentIndex(block);
         if (commitpos != -1) {
             bool malleated = false;
diff --git a/src/validation.h b/src/validation.h
index d747fdbf27..585a42849d 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -383,12 +383,10 @@ bool CheckBlock(const CBlock& block, CValidationState& state, const Consensus::P
 /** Check a block is completely valid from start to finish (only works on top of our current best block) */
 bool TestBlockValidity(CValidationState& state, const CChainParams& chainparams, const CBlock& block, CBlockIndex* pindexPrev, bool fCheckPOW = true, bool fCheckMerkleRoot = true) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
-/** Check whether witness commitments are required for block. */
+/** Check whether witness commitments are required for a block, and whether to enforce NULLDUMMY (BIP 147) rules.
+ *  Note that transaction witness validation rules are always enforced when P2SH is enforced. */
 bool IsWitnessEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params);
 
-/** Check whether NULLDUMMY (BIP 147) has activated. */
-bool IsNullDummyEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params);
-
 /** When there are blocks in the active chain with missing data, rewind the chainstate and remove them from the block index */
 bool RewindBlockIndex(const CChainParams& params) LOCKS_EXCLUDED(cs_main);
 
diff --git a/src/versionbitsinfo.cpp b/src/versionbitsinfo.cpp
index 60bfaace99..82df92ac90 100644
--- a/src/versionbitsinfo.cpp
+++ b/src/versionbitsinfo.cpp
@@ -11,8 +11,4 @@ const struct VBDeploymentInfo VersionBitsDeploymentInfo[Consensus::MAX_VERSION_B
         /*.name =*/ "testdummy",
         /*.gbt_force =*/ true,
     },
-    {
-        /*.name =*/ "segwit",
-        /*.gbt_force =*/ true,
-    }
 };