Activate CSV from genesis block for custom chains

src/chainparams.cpp

@@ -567,7 +567,12 @@ class CCustomParams : public CRegTestParams {
         parent_bech32_hrp = args.GetArg("-parent_bech32_hrp", "bcrt");
 
         // END ELEMENTS fields
-        //
+
+        // CSV always active by default, unlike regtest
+        consensus.vDeployments[Consensus::DEPLOYMENT_CSV].bit = 0;
+        consensus.vDeployments[Consensus::DEPLOYMENT_CSV].nStartTime = args.GetArg("-con_csv_deploy_start", Consensus::BIP9Deployment::ALWAYS_ACTIVE);
+        consensus.vDeployments[Consensus::DEPLOYMENT_CSV].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+
     }
 
     void SetGenesisBlock() {

src/chainparamsbase.cpp

@@ -42,6 +42,7 @@ void SetupChainParamsBaseOptions()
     gArgs.AddArg("-enforce_pak", "Causes standardness checks to enforce Pegout Authorization Key(PAK) validation, and miner to include PAK commitments when configured. Can not be set when acceptnonstdtx is set to true.", false, OptionsCategory::ELEMENTS);
     gArgs.AddArg("-multi_data_permitted", "Allow relay of multiple OP_RETURN outputs. (default: true)", false, OptionsCategory::ELEMENTS);
     gArgs.AddArg("-pak", "Entries in the PAK list. Order of entries matter.", false, OptionsCategory::ELEMENTS);
+    gArgs.AddArg("-con_csv_deploy_start", "Starting height for CSV deployment. (default: -1, which means ACTIVE from genesis)", false, OptionsCategory::ELEMENTS);
 }
 
 static std::unique_ptr<CBaseChainParams> globalChainBaseParams;

test/bitcoin_functional/functional/test_framework/util.py

@@ -315,6 +315,7 @@ def initialize_datadir(dirname, n, chain):
         f.write("con_bip65height=1351\n")
         f.write("con_bip66height=1251\n")
         f.write("con_genesis_style=bitcoin\n")
+        f.write("con_csv_deploy_start=0\n") # Default is -1 (always active)
         os.makedirs(os.path.join(datadir, 'stderr'), exist_ok=True)
         os.makedirs(os.path.join(datadir, 'stdout'), exist_ok=True)
     return datadir

test/functional/feature_block_v4.py

@@ -2,23 +2,28 @@
 # Copyright (c) 2015-2018 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
-"""Test BIP 34, 65, 66 activation at block 0"""
+"""Test BIP 34, 65, 66, CSV activation at block 0"""
 
 from test_framework.blocktools import create_coinbase, create_block, create_transaction
 from test_framework.messages import msg_block
 from test_framework.mininode import P2PInterface
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal
+from test_framework.util import assert_equal, get_bip9_status
 
 from feature_cltv import cltv_validate
 
 class BlockV4Test(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 1
-        self.extra_args = [['-whitelist=127.0.0.1', '-con_bip34height=0', '-con_bip65height=0', '-con_bip66height=0']]
+        self.extra_args = [['-whitelist=127.0.0.1', '-con_bip34height=0', '-con_bip65height=0', '-con_bip66height=0', '-con_csv_deploy_start=-1']]
         self.setup_clean_chain = True
 
     def run_test(self):
+
+        # First, quick check that CSV is ACTIVE at genesis
+        assert_equal(self.nodes[0].getblockcount(), 0)
+        assert_equal(get_bip9_status(self.nodes[0], 'csv')['status'], 'active')
+
         self.nodes[0].add_p2p_connection(P2PInterface())
 
         self.nodeaddress = self.nodes[0].getnewaddress()

test/functional/test_framework/util.py

@@ -321,6 +321,7 @@ def initialize_datadir(dirname, n, chain):
         f.write("con_bip34height=100000000\n")
         f.write("con_bip65height=1351\n")
         f.write("con_bip66height=1251\n")
+        f.write("con_csv_deploy_start=0\n") # Enhance tests if removing this line
         os.makedirs(os.path.join(datadir, 'stderr'), exist_ok=True)
         os.makedirs(os.path.join(datadir, 'stdout'), exist_ok=True)
     return datadir