Merge bitcoin/bitcoin#21090: Default to NODE_WITNESS in nLocalServices

a806647d260132a00cd633160040625c7dd17803 [validation] Always include merkle root in coinbase commitment (Dhruv Mehta)
189128c220190a588500b8e74ee7ae47671b9558 [validation] Set witness script flag with p2sh for blocks (Dhruv Mehta)
ac82b99db77ec843af82dcdf040dfdbc98c8ff26 [p2p] remove redundant NODE_WITNESS checks (Dhruv Mehta)
6f8b198b8256a6703a6f5e592dfa77fa024a7035 [p2p] remove unused segwitheight=-1 option (Dhruv Mehta)
eba5b1cd6460c98e75d0422bd394e12af7f11e4c [test] remove or move tests using `-segwitheight=-1` (Dhruv Mehta)

Pull request description:

  Builds on #21009 and makes progress on remaining items in #17862

  Removing `RewindBlockIndex()` in #21009 allows the following:

  - removal of tests using `segwitheight=-1` in `p2p_segwit.py`.
  - move `test_upgrade_after_activation()` out of `p2p_segwit.py` reducing runtime
  - in turn, that allows us to drop support for `-segwitheight=-1`, which is only supported for that test.
  - that allows us to always set `NODE_WITNESS` in our local services. The only reason we don't do that is to support `-segwitheight=-1`.
  - that in turn allows us to drop all of the `GetLocalServices() & NODE_WITNESS` checks inside `net_processing.cpp`, since our local services would always include `NODE_WITNESS`

ACKs for top commit:
  mzumsande:
    Code-Review ACK a806647d260132a00cd633160040625c7dd17803
  laanwj:
    Code review ACK a806647d260132a00cd633160040625c7dd17803, nice cleanup
  jnewbery:
    utACK a806647d260132a00cd633160040625c7dd17803
  theStack:
    ACK a806647d260132a00cd633160040625c7dd17803

Tree-SHA512: 73e1a69d1d7eca1f5c38558ec6672decd0b60b16c2ef6134df6f6af71bb159e6eea160f9bb5ab0eb6723c6632d29509811e29469d0d87abbe9b69a2890fbc73e

5 files changed, 28 insertions, 48 deletions

diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index eb6c382f23..a8b45685d0 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -490,11 +490,8 @@ void CRegTestParams::UpdateActivationParametersFromArgs(const ArgsManager& args)
 {
     if (args.IsArgSet("-segwitheight")) {
         int64_t height = args.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();
+        if (height < 0 || height >= std::numeric_limits<int>::max()) {
+            throw std::runtime_error(strprintf("Activation height %ld for segwit is out of valid range.", height));
         }
         consensus.SegwitHeight = static_cast<int>(height);
     }
diff --git a/src/chainparamsbase.cpp b/src/chainparamsbase.cpp
index e71b4bc859..79c1bc25bc 100644
--- a/src/chainparamsbase.cpp
+++ b/src/chainparamsbase.cpp
@@ -20,7 +20,7 @@ void SetupChainParamsBaseOptions(ArgsManager& argsman)
     argsman.AddArg("-chain=<chain>", "Use the chain <chain> (default: main). Allowed values: main, test, signet, regtest", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
     argsman.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. Equivalent to -chain=regtest.", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
-    argsman.AddArg("-segwitheight=<n>", "Set the activation height of segwit. -1 to disable. (regtest-only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
+    argsman.AddArg("-segwitheight=<n>", "Set the activation height of segwit. (regtest-only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-testnet", "Use the test chain. Equivalent to -chain=test.", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
     argsman.AddArg("-vbparams=deployment:start:end[:min_activation_height]", "Use given start/end times and min_activation_height for specified version bits deployment (regtest-only)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CHAINPARAMS);
     argsman.AddArg("-signet", "Use the signet chain. Equivalent to -chain=signet. Note that the network is defined by the -signetchallenge parameter", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
diff --git a/src/init.cpp b/src/init.cpp
index 3915fa8fcb..75394d96b1 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -715,7 +715,7 @@ namespace { // Variables internal to initialization process only
 int nMaxConnections;
 int nUserMaxConnections;
 int nFD;
-ServiceFlags nLocalServices = ServiceFlags(NODE_NETWORK | NODE_NETWORK_LIMITED);
+ServiceFlags nLocalServices = ServiceFlags(NODE_NETWORK | NODE_NETWORK_LIMITED | NODE_WITNESS);
 int64_t peer_connect_timeout;
 std::set<BlockFilterType> g_enabled_filter_types;
 
@@ -1588,12 +1588,6 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         }
     }
 
-    if (DeploymentEnabled(chainparams.GetConsensus(), Consensus::DEPLOYMENT_SEGWIT)) {
-        // 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);
-    }
-
     // ********************************************************* Step 11: import blocks
 
     if (!CheckDiskSpace(gArgs.GetDataDirNet())) {
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 44f9879a23..a0c346b99f 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -877,7 +877,7 @@ void PeerManagerImpl::MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid)
         }
         m_connman.ForNode(nodeid, [this](CNode* pfrom) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
             AssertLockHeld(::cs_main);
-            uint64_t nCMPCTBLOCKVersion = (pfrom->GetLocalServices() & NODE_WITNESS) ? 2 : 1;
+            uint64_t nCMPCTBLOCKVersion = 2;
             if (lNodesAnnouncingHeaderAndIDs.size() >= 3) {
                 // As per BIP152, we only get 3 of our peers to announce
                 // blocks using compact encodings.
@@ -1973,7 +1973,7 @@ void PeerManagerImpl::ProcessGetData(CNode& pfrom, Peer& peer, const std::atomic
 
 static uint32_t GetFetchFlags(const CNode& pfrom) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     uint32_t nFetchFlags = 0;
-    if ((pfrom.GetLocalServices() & NODE_WITNESS) && State(pfrom.GetId())->fHaveWitness) {
+    if (State(pfrom.GetId())->fHaveWitness) {
         nFetchFlags |= MSG_WITNESS_FLAG;
     }
     return nFetchFlags;
@@ -2688,8 +2688,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             // they may wish to request compact blocks from us
             bool fAnnounceUsingCMPCTBLOCK = false;
             uint64_t nCMPCTBLOCKVersion = 2;
-            if (pfrom.GetLocalServices() & NODE_WITNESS)
-                m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion));
+            m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion));
             nCMPCTBLOCKVersion = 1;
             m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion));
         }
@@ -2707,7 +2706,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
         bool fAnnounceUsingCMPCTBLOCK = false;
         uint64_t nCMPCTBLOCKVersion = 0;
         vRecv >> fAnnounceUsingCMPCTBLOCK >> nCMPCTBLOCKVersion;
-        if (nCMPCTBLOCKVersion == 1 || ((pfrom.GetLocalServices() & NODE_WITNESS) && nCMPCTBLOCKVersion == 2)) {
+        if (nCMPCTBLOCKVersion == 1 || nCMPCTBLOCKVersion == 2) {
             LOCK(cs_main);
             // fProvidesHeaderAndIDs is used to "lock in" version of compact blocks we send (fWantsCmpctWitness)
             if (!State(pfrom.GetId())->fProvidesHeaderAndIDs) {
@@ -2721,10 +2720,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
                 pfrom.m_bip152_highbandwidth_from = fAnnounceUsingCMPCTBLOCK;
             }
             if (!State(pfrom.GetId())->fSupportsDesiredCmpctVersion) {
-                if (pfrom.GetLocalServices() & NODE_WITNESS)
-                    State(pfrom.GetId())->fSupportsDesiredCmpctVersion = (nCMPCTBLOCKVersion == 2);
-                else
-                    State(pfrom.GetId())->fSupportsDesiredCmpctVersion = (nCMPCTBLOCKVersion == 1);
+                State(pfrom.GetId())->fSupportsDesiredCmpctVersion = (nCMPCTBLOCKVersion == 2);
             }
         }
         return;
diff --git a/src/validation.cpp b/src/validation.cpp
index f81c27e8e3..842687e4d6 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1645,13 +1645,8 @@ static unsigned int GetBlockScriptFlags(const CBlockIndex* pindex, const Consens
         pindex->phashBlock == nullptr || // this is a new candidate block, eg from TestBlockValidity()
         *pindex->phashBlock != consensusparams.BIP16Exception) // this block isn't the historical exception
     {
-        flags |= SCRIPT_VERIFY_P2SH;
-    }
-
-    // Enforce WITNESS rules whenever P2SH is in effect (and the segwit
-    // deployment is defined).
-    if (flags & SCRIPT_VERIFY_P2SH && DeploymentEnabled(consensusparams, Consensus::DEPLOYMENT_SEGWIT)) {
-        flags |= SCRIPT_VERIFY_WITNESS;
+        // Enforce WITNESS rules whenever P2SH is in effect
+        flags |= SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS;
     }
 
     // Enforce the DERSIG (BIP66) rule
@@ -3101,25 +3096,23 @@ 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 (DeploymentEnabled(consensusParams, Consensus::DEPLOYMENT_SEGWIT)) {
-        if (commitpos == NO_WITNESS_COMMITMENT) {
-            uint256 witnessroot = BlockWitnessMerkleRoot(block, nullptr);
-            CHash256().Write(witnessroot).Write(ret).Finalize(witnessroot);
-            CTxOut out;
-            out.nValue = 0;
-            out.scriptPubKey.resize(MINIMUM_WITNESS_COMMITMENT);
-            out.scriptPubKey[0] = OP_RETURN;
-            out.scriptPubKey[1] = 0x24;
-            out.scriptPubKey[2] = 0xaa;
-            out.scriptPubKey[3] = 0x21;
-            out.scriptPubKey[4] = 0xa9;
-            out.scriptPubKey[5] = 0xed;
-            memcpy(&out.scriptPubKey[6], witnessroot.begin(), 32);
-            commitment = std::vector<unsigned char>(out.scriptPubKey.begin(), out.scriptPubKey.end());
-            CMutableTransaction tx(*block.vtx[0]);
-            tx.vout.push_back(out);
-            block.vtx[0] = MakeTransactionRef(std::move(tx));
-        }
+    if (commitpos == NO_WITNESS_COMMITMENT) {
+        uint256 witnessroot = BlockWitnessMerkleRoot(block, nullptr);
+        CHash256().Write(witnessroot).Write(ret).Finalize(witnessroot);
+        CTxOut out;
+        out.nValue = 0;
+        out.scriptPubKey.resize(MINIMUM_WITNESS_COMMITMENT);
+        out.scriptPubKey[0] = OP_RETURN;
+        out.scriptPubKey[1] = 0x24;
+        out.scriptPubKey[2] = 0xaa;
+        out.scriptPubKey[3] = 0x21;
+        out.scriptPubKey[4] = 0xa9;
+        out.scriptPubKey[5] = 0xed;
+        memcpy(&out.scriptPubKey[6], witnessroot.begin(), 32);
+        commitment = std::vector<unsigned char>(out.scriptPubKey.begin(), out.scriptPubKey.end());
+        CMutableTransaction tx(*block.vtx[0]);
+        tx.vout.push_back(out);
+        block.vtx[0] = MakeTransactionRef(std::move(tx));
     }
     UpdateUncommittedBlockStructures(block, pindexPrev, consensusParams);
     return commitment;