chainparams: Add support for renouncing an HereticalDeployment

Author: ajtowns

src/chainparams.cpp

@@ -23,6 +23,25 @@
 
 using util::SplitString;
 
+static void HandleRenounceArgs(const ArgsManager& args, CChainParams::RenounceParameters& renounce)
+{
+    if (!args.IsArgSet("-renounce")) return;
+    for (const std::string& dep_name : args.GetArgs("-renounce")) {
+        bool found = false;
+        for (int j = 0; j < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; ++j) {
+            if (dep_name == VersionBitsDeploymentInfo[j].name) {
+                renounce.emplace_back(static_cast<Consensus::BuriedDeployment>(j));
+                found = true;
+                LogPrintf("Disabling deployment %s\n", dep_name);
+                break;
+            }
+        }
+        if (!found) {
+            throw std::runtime_error(strprintf("Invalid deployment (%s)", dep_name));
+        }
+    }
+}
+
 void ReadSigNetArgs(const ArgsManager& args, CChainParams::SigNetOptions& options)
 {
     if (args.IsArgSet("-signetseednode")) {
@@ -39,6 +58,7 @@ void ReadSigNetArgs(const ArgsManager& args, CChainParams::SigNetOptions& option
         }
         options.challenge.emplace(*val);
     }
+    HandleRenounceArgs(args, options.renounce);
 }
 
 void ReadRegTestArgs(const ArgsManager& args, CChainParams::RegTestOptions& options)
@@ -65,6 +85,8 @@ void ReadRegTestArgs(const ArgsManager& args, CChainParams::RegTestOptions& opti
         }
     }
 
+    HandleRenounceArgs(args, options.renounce);
+
     if (!args.IsArgSet("-vbparams")) return;
 
     for (const std::string& strDeployment : args.GetArgs("-vbparams")) {

src/chainparamsbase.cpp

@@ -20,6 +20,7 @@ void SetupChainParamsBaseOptions(ArgsManager& argsman)
     argsman.AddArg("-testnet", "Use the testnet3 chain. Equivalent to -chain=test. Support for testnet3 is deprecated and will be removed in an upcoming release. Consider moving to testnet4 now by using -testnet4.", ArgsManager::ALLOW_ANY, OptionsCategory::CHAINPARAMS);
     argsman.AddArg("-testnet4", "Use the testnet4 chain. Equivalent to -chain=testnet4.", 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("-renounce=deployment", "Unconditionally disable an heretical deployment attempt", 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);
     argsman.AddArg("-signetchallenge", "Blocks must satisfy the given script to be considered valid (only for signet networks; defaults to the global default signet test network challenge)", ArgsManager::ALLOW_ANY | ArgsManager::DISALLOW_NEGATION, OptionsCategory::CHAINPARAMS);
     argsman.AddArg("-signetseednode", "Specify a seed node for the signet network, in the hostname[:port] format, e.g. sig.net:1234 (may be used multiple times to specify multiple seed nodes; defaults to the global default signet test network seed node(s))", ArgsManager::ALLOW_ANY | ArgsManager::DISALLOW_NEGATION, OptionsCategory::CHAINPARAMS);

src/kernel/chainparams.cpp

@@ -75,6 +75,15 @@ static CBlock CreateGenesisBlock(uint32_t nTime, uint32_t nNonce, uint32_t nBits
     return CreateGenesisBlock(pszTimestamp, genesisOutputScript, nTime, nNonce, nBits, nVersion, genesisReward);
 }
 
+template<size_t N>
+static void RenounceDeployments(const CChainParams::RenounceParameters& renounce, Consensus::HereticalDeployment (&vDeployments)[N])
+{
+    for (Consensus::BuriedDeployment dep : renounce) {
+        vDeployments[dep].nStartTime = Consensus::HereticalDeployment::NEVER_ACTIVE;
+        vDeployments[dep].nTimeout = Consensus::HereticalDeployment::NO_TIMEOUT;
+    }
+}
+
 namespace {
 struct SetupDeployment
 {
@@ -473,6 +482,8 @@ class SigNetParams : public CChainParams {
         consensus.powLimit = uint256{"00000377ae000000000000000000000000000000000000000000000000000000"};
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY] = SetupDeployment{.activate = 0x30000000, .abandon = 0, .never = true};
 
+        RenounceDeployments(options.renounce, consensus.vDeployments);
+
         // message start is defined as the first 4 bytes of the sha256d of the block script
         HashWriter h{};
         h << consensus.signet_challenge;
@@ -584,6 +595,8 @@ class CRegTestParams : public CChainParams
             consensus.vDeployments[deployment_pos].nTimeout = version_bits_params.timeout;
         }
 
+        RenounceDeployments(opts.renounce, consensus.vDeployments);
+
         genesis = CreateGenesisBlock(1296688602, 2, 0x207fffff, 1, 50 * COIN);
         consensus.hashGenesisBlock = genesis.GetHash();
         assert(consensus.hashGenesisBlock == uint256{"0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206"});

src/kernel/chainparams.h

@@ -136,12 +136,15 @@ class CChainParams
 
     const ChainTxData& TxData() const { return chainTxData; }
 
+    using RenounceParameters = std::vector<Consensus::BuriedDeployment>;
+
     /**
      * SigNetOptions holds configurations for creating a signet CChainParams.
      */
     struct SigNetOptions {
         std::optional<std::vector<uint8_t>> challenge{};
         std::optional<std::vector<std::string>> seeds{};
+        RenounceParameters renounce{};
     };
 
     /**
@@ -158,6 +161,7 @@ class CChainParams
     struct RegTestOptions {
         std::unordered_map<Consensus::DeploymentPos, VersionBitsParameters> version_bits_parameters{};
         std::unordered_map<Consensus::BuriedDeployment, int> activation_heights{};
+        RenounceParameters renounce{};
         bool fastprune{false};
     };