Merge #6189: backport: bitcoin#16333, bitcoin#21862, bitcoin#22385, b…

…itcoin#22550, bitcoin#22597, bitcoin#22632, bitcoin#22718, bitcoin#22907 - fire up test chains by first block - 2/n

e4e7c44 fix: use proper chain instead using ActiveChain for test framework (Konstantin Akimov)
65b92fa Merge bitcoin#21862: test: Set regtest.BIP65Height = 111 to speed up tests (fanquake)
adcf095 Merge bitcoin#22718: doc: Add missing PR 16333 release note (MarcoFalke)
101a863 Merge bitcoin#16333: test: Set BIP34Height = 2 for regtest (MarcoFalke)
71af881 Merge bitcoin#22907: test: Avoid intermittent test failure in feature_csv_activation.py (merge-script)
fc25503 Merge bitcoin#22632: test: Set regtest.BIP66Height = 102 to speed up tests (W. J. van der Laan)
cbd2be8 Merge bitcoin#22597: consensus/params: simplify ValidDeployment check to avoid gcc warning (MarcoFalke)
8928146 Merge bitcoin#22550: test: improve `test_signing_with_{csv,cltv}` subtests (speed, prevent timeout) (MarcoFalke)
fb00431 Merge bitcoin#22385: refactor: Use DeploymentEnabled to hide VB deployments (MarcoFalke)

Pull request description:

  ## Issue being fixed or feature implemented
  Backports from bitcoin related to hard-fork mechanism and accelerated action

  ## What was done?
  see commits for backports.
  Also fixed an issue of using from ChainState on RegTest: should be used specified chain, not the "best chain".

  ## How Has This Been Tested?
  Run unit & functional tests

  ## Breaking Changes
  That's a breaking changes for RegTest

  ## Checklist:
  - [x] I have performed a self-review of my own code
  - [ ] I have commented my code, particularly in hard-to-understand areas
  - [ ] I have added or updated relevant unit/integration/functional/e2e tests
  - [ ] I have made corresponding changes to the documentation
  - [x] I have assigned this pull request to a milestone

ACKs for top commit:
  PastaPastaPasta:
    utACK e4e7c44

Tree-SHA512: c02813179177781a0da3beaff65732e12017f0056565b897891b2c5a06fda125a4e032571a02fad9d8640728df82c117393bd78bc6d406e0a30f72587b2d7344

doc/release-notes-6189.md

@@ -0,0 +1,8 @@
+Tests
+-----
+
+- For the `regtest` network the activation heights of several softforks were
+  changed. (dash#6189)
+  * BIP 34 (blockheight in coinbase) from 500 to 2
+  * BIP 66 (DERSIG) from 1251 to 102
+  * BIP 65 (CLTV) from 1351 to 111

src/chainparams.cpp

@@ -794,10 +794,10 @@ class CRegTestParams : public CChainParams {
         consensus.nGovernanceMinQuorum = 1;
         consensus.nGovernanceFilterElements = 100;
         consensus.nMasternodeMinimumConfirmations = 1;
-        consensus.BIP34Height = 500; // BIP34 activated on regtest (Used in functional tests)
+        consensus.BIP34Height = 2; // BIP34 activated on regtest (Block at height 1 not enforced for testing purposes)
         consensus.BIP34Hash = uint256();
-        consensus.BIP65Height = 1351; // BIP65 activated on regtest (Used in functional tests)
-        consensus.BIP66Height = 1251; // BIP66 activated on regtest (Used in functional tests)
+        consensus.BIP65Height = 111; // BIP65 activated on regtest (Block at height 110 and earlier not enforced for testing purposes)
+        consensus.BIP66Height = 102; // BIP66 activated on regtest (Block at height 101 and earlier not enforced for testing purposes)
         consensus.BIP147Height = 432; // BIP147 activated on regtest (Used in functional tests)
         consensus.CSVHeight = 432; // CSV activated on regtest (Used in rpc activation tests)
         consensus.DIP0001Height = 2000;

src/consensus/params.h

@@ -14,8 +14,12 @@
 
 namespace Consensus {
 
-enum BuriedDeployment : int16_t
-{
+/**
+ * A buried deployment is one where the height of the activation has been hardcoded into
+ * the client implementation long after the consensus change has activated. See BIP 90.
+ */
+enum BuriedDeployment : int16_t {
+    // buried deployments get negative values to avoid overlap with DeploymentPos
     DEPLOYMENT_HEIGHTINCB = std::numeric_limits<int16_t>::min(),
     DEPLOYMENT_DERSIG,
     DEPLOYMENT_CLTV,
@@ -29,17 +33,16 @@ enum BuriedDeployment : int16_t
     DEPLOYMENT_BRR,
     DEPLOYMENT_V19,
 };
-constexpr bool ValidDeployment(BuriedDeployment dep) { return DEPLOYMENT_HEIGHTINCB <= dep && dep <= DEPLOYMENT_V19; }
+constexpr bool ValidDeployment(BuriedDeployment dep) { return dep <= DEPLOYMENT_V19; }
 
-enum DeploymentPos : uint16_t
-{
+enum DeploymentPos : uint16_t {
     DEPLOYMENT_TESTDUMMY,
     DEPLOYMENT_V20,     // Deployment of EHF, LLMQ Randomness Beacon
     DEPLOYMENT_MN_RR,   // Deployment of Masternode Reward Location Reallocation
     // NOTE: Also add new deployments to VersionBitsDeploymentInfo in deploymentinfo.cpp
     MAX_VERSION_BITS_DEPLOYMENTS
 };
-constexpr bool ValidDeployment(DeploymentPos dep) { return DEPLOYMENT_TESTDUMMY <= dep && dep <= DEPLOYMENT_MN_RR; }
+constexpr bool ValidDeployment(DeploymentPos dep) { return dep < MAX_VERSION_BITS_DEPLOYMENTS; }
 
 /**
  * Struct for each individual consensus rule change using BIP9.

src/deploymentstatus.cpp

@@ -7,6 +7,8 @@
 #include <consensus/params.h>
 #include <versionbits.h>
 
+#include <type_traits>
+
 VersionBitsCache g_versionbitscache;
 
 /* Basic sanity checking for BuriedDeployment/DeploymentPos enums and
@@ -15,3 +17,18 @@ VersionBitsCache g_versionbitscache;
 static_assert(ValidDeployment(Consensus::DEPLOYMENT_TESTDUMMY), "sanity check of DeploymentPos failed (TESTDUMMY not valid)");
 static_assert(!ValidDeployment(Consensus::MAX_VERSION_BITS_DEPLOYMENTS), "sanity check of DeploymentPos failed (MAX value considered valid)");
 static_assert(!ValidDeployment(static_cast<Consensus::BuriedDeployment>(Consensus::DEPLOYMENT_TESTDUMMY)), "sanity check of BuriedDeployment failed (overlaps with DeploymentPos)");
+
+/* ValidDeployment only checks upper bounds for ensuring validity.
+ * This checks that the lowest possible value or the type is also a
+ * (specific) valid deployment so that lower bounds don't need to be checked.
+ */
+
+template<typename T, T x>
+static constexpr bool is_minimum()
+{
+    using U = typename std::underlying_type<T>::type;
+    return x == std::numeric_limits<U>::min();
+}
+
+static_assert(is_minimum<Consensus::BuriedDeployment, Consensus::DEPLOYMENT_HEIGHTINCB>(), "heightincb is not minimum value for BuriedDeployment");
+static_assert(is_minimum<Consensus::DeploymentPos, Consensus::DEPLOYMENT_TESTDUMMY>(), "testdummy is not minimum value for DeploymentPos");

src/deploymentstatus.h

@@ -49,7 +49,7 @@ inline bool DeploymentEnabled(const Consensus::Params& params, Consensus::Buried
 inline bool DeploymentEnabled(const Consensus::Params& params, Consensus::DeploymentPos dep)
 {
     assert(Consensus::ValidDeployment(dep));
-    return params.vDeployments[dep].nTimeout != 0;
+    return params.vDeployments[dep].nStartTime != Consensus::BIP9Deployment::NEVER_ACTIVE;
 }
 
 /** this function is convenient helper for DIP0003 because 'active' and 'enforced' are different statuses for DIP0003 */

src/miner.cpp

@@ -64,9 +64,9 @@ BlockAssembler::Options::Options()
 }
 
 BlockAssembler::BlockAssembler(CChainState& chainstate, const NodeContext& node, const CTxMemPool& mempool, const CChainParams& params, const Options& options) :
-      m_blockman(Assert(node.chainman)->m_blockman),
+      m_blockman(chainstate.m_blockman),
       m_cpoolman(*Assert(node.cpoolman)),
-      m_chain_helper(*Assert(node.chain_helper)),
+      m_chain_helper(chainstate.ChainHelper()),
       m_chainstate(chainstate),
       m_dmnman(*Assert(node.dmnman)),
       m_evoDb(*Assert(node.evodb)),

src/rpc/blockchain.cpp

@@ -1620,10 +1620,7 @@ static RPCHelpMan verifychain()
 static void SoftForkDescPushBack(const CBlockIndex* active_chain_tip, UniValue& softforks, const Consensus::Params& params, Consensus::BuriedDeployment dep)
 {
     // For buried deployments.
-    // A buried deployment is one where the height of the activation has been hardcoded into
-    // the client implementation long after the consensus change has activated. See BIP 90.
-    // Buried deployments with activation height value of
-    // std::numeric_limits<int>::max() are disabled and thus hidden.
+
     if (!DeploymentEnabled(params, dep)) return;
 
     UniValue rv(UniValue::VOBJ);
@@ -1638,8 +1635,8 @@ static void SoftForkDescPushBack(const CBlockIndex* active_chain_tip, UniValue&
 static void SoftForkDescPushBack(const CBlockIndex* active_chain_tip, const std::unordered_map<uint8_t, int>& signals, UniValue& softforks, const Consensus::Params& consensusParams, Consensus::DeploymentPos id)
 {
     // For BIP9 deployments.
-    // Deployments that are never active are hidden.
-    if (consensusParams.vDeployments[id].nStartTime == Consensus::BIP9Deployment::NEVER_ACTIVE) return;
+
+    if (!DeploymentEnabled(consensusParams, id)) return;
 
     UniValue bip9(UniValue::VOBJ);
     const ThresholdState thresholdState = g_versionbitscache.State(active_chain_tip, consensusParams, id);

src/test/util/setup_common.cpp

@@ -428,10 +428,10 @@ CBlock TestChainSetup::CreateBlock(
         auto cbTx = GetTxPayload<CCbTx>(*block.vtx[0]);
         BOOST_ASSERT(cbTx.has_value());
         BlockValidationState state;
-        if (!CalcCbTxMerkleRootMNList(block, m_node.chainman->ActiveChain().Tip(), cbTx->merkleRootMNList, *m_node.dmnman, state, m_node.chainman->ActiveChainstate().CoinsTip())) {
+        if (!CalcCbTxMerkleRootMNList(block, chainstate.m_chain.Tip(), cbTx->merkleRootMNList, *m_node.dmnman, state, chainstate.CoinsTip())) {
             BOOST_ASSERT(false);
         }
-        if (!CalcCbTxMerkleRootQuorums(block, m_node.chainman->ActiveChain().Tip(), *m_node.llmq_ctx->quorum_block_processor, cbTx->merkleRootQuorums, state)) {
+        if (!CalcCbTxMerkleRootQuorums(block, chainstate.m_chain.Tip(), *m_node.llmq_ctx->quorum_block_processor, cbTx->merkleRootQuorums, state)) {
             BOOST_ASSERT(false);
         }
         CMutableTransaction tmpTx{*block.vtx[0]};
@@ -443,7 +443,7 @@ CBlock TestChainSetup::CreateBlock(
     {
         LOCK(cs_main);
         unsigned int extraNonce = 0;
-        IncrementExtraNonce(&block, m_node.chainman->ActiveChain().Tip(), extraNonce);
+        IncrementExtraNonce(&block, chainstate.m_chain.Tip(), extraNonce);
     }
 
     while (!CheckProofOfWork(block.GetHash(), block.nBits, chainparams.GetConsensus())) ++block.nNonce;

src/test/validation_block_tests.cpp

@@ -79,6 +79,8 @@ std::shared_ptr<CBlock> MinerTestingSetup::Block(const uint256& prev_hash)
     txCoinbase.vout[1].scriptPubKey = P2SH_OP_TRUE;
     txCoinbase.vout[1].nValue = txCoinbase.vout[0].nValue;
     txCoinbase.vout[0].nValue = 0;
+    // Always pad with OP_0 at the end to avoid bad-cb-length error
+    txCoinbase.vin[0].scriptSig = CScript{} << WITH_LOCK(::cs_main, return m_node.chainman->m_blockman.LookupBlockIndex(prev_hash)->nHeight + 1) << OP_0;
     pblock->vtx[0] = MakeTransactionRef(std::move(txCoinbase));
 
     return pblock;
@@ -92,6 +94,11 @@ std::shared_ptr<CBlock> MinerTestingSetup::FinalizeBlock(std::shared_ptr<CBlock>
         ++(pblock->nNonce);
     }
 
+    // submit block header, so that miner can get the block height from the
+    // global state and the node has the topology of the chain
+    BlockValidationState ignored;
+    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlockHeaders({pblock->GetBlockHeader()}, ignored, Params()));
+
     return pblock;
 }
 
@@ -146,13 +153,6 @@ BOOST_AUTO_TEST_CASE(processnewblock_signals_ordering)
     }
 
     bool ignored;
-    BlockValidationState state;
-    std::vector<CBlockHeader> headers;
-    std::transform(blocks.begin(), blocks.end(), std::back_inserter(headers), [](std::shared_ptr<const CBlock> b) { return b->GetBlockHeader(); });
-
-    // Process all the headers so we understand the toplogy of the chain
-    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlockHeaders(headers, state, Params()));
-
     // Connect the genesis block and drain any outstanding events
     BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlock(Params(), std::make_shared<CBlock>(Params().GenesisBlock()), true, &ignored));
     SyncWithValidationInterfaceQueue();

test/functional/feature_block.py

@@ -378,7 +378,9 @@ def run_test(self):
         # b30 has a max-sized coinbase scriptSig.
         self.move_tip(23)
         b30 = self.next_block(30)
-        b30.vtx[0].vin[0].scriptSig = b'\x00' * 100
+        b30.vtx[0].vin[0].scriptSig = bytes(b30.vtx[0].vin[0].scriptSig)  # Convert CScript to raw bytes
+        b30.vtx[0].vin[0].scriptSig += b'\x00' * (100 - len(b30.vtx[0].vin[0].scriptSig))  # Fill with 0s
+        assert_equal(len(b30.vtx[0].vin[0].scriptSig), 100)
         b30.vtx[0].rehash()
         b30 = self.update_block(30, [])
         self.send_blocks([b30], True)
@@ -839,6 +841,7 @@ def run_test(self):
         b61.vtx[0].rehash()
         b61 = self.update_block(61, [])
         assert_equal(duplicate_tx.serialize(), b61.vtx[0].serialize())
+        # BIP30 is always checked on regtest, regardless of the BIP34 activation height
         self.send_blocks([b61], success=False, reject_reason='bad-txns-BIP30', reconnect=True)
 
         # Test BIP30 (allow duplicate if spent)

test/functional/feature_cltv.py

@@ -4,11 +4,11 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test BIP65 (CHECKLOCKTIMEVERIFY).
 
-Test that the CHECKLOCKTIMEVERIFY soft-fork activates at (regtest) block height
-1351.
+Test that the CHECKLOCKTIMEVERIFY soft-fork activates.
 """
 
 from test_framework.blocktools import (
+    CLTV_HEIGHT,
     create_block,
     create_coinbase,
 )
@@ -34,8 +34,6 @@
     MiniWalletMode,
 )
 
-CLTV_HEIGHT = 1351
-
 
 # Helper function to modify a transaction by
 # 1) prepending a given script to the scriptSig of vin 0 and
@@ -66,9 +64,9 @@ def cltv_invalidate(tx, failure_reason):
         # +-------------------------------------------------+------------+--------------+
         [[OP_CHECKLOCKTIMEVERIFY],                            None,       None],
         [[OP_1NEGATE, OP_CHECKLOCKTIMEVERIFY, OP_DROP],       None,       None],
-        [[CScriptNum(1000), OP_CHECKLOCKTIMEVERIFY, OP_DROP], 0,          1296688602],  # timestamp of genesis block
-        [[CScriptNum(1000), OP_CHECKLOCKTIMEVERIFY, OP_DROP], 0,          500],
-        [[CScriptNum(500),  OP_CHECKLOCKTIMEVERIFY, OP_DROP], 0xffffffff, 500],
+        [[CScriptNum(100), OP_CHECKLOCKTIMEVERIFY, OP_DROP],  0,          1296688602],  # timestamp of genesis block
+        [[CScriptNum(100), OP_CHECKLOCKTIMEVERIFY, OP_DROP],  0,          50],
+        [[CScriptNum(50),  OP_CHECKLOCKTIMEVERIFY, OP_DROP],  0xffffffff, 50],
     ][failure_reason]
 
     cltv_modify_tx(tx, prepend_scriptsig=scheme[0], nsequence=scheme[1], nlocktime=scheme[2])
@@ -111,6 +109,7 @@ def run_test(self):
         self.log.info("Mining %d blocks", CLTV_HEIGHT - 2)
         wallet.generate(10)
         self.nodes[0].generate(CLTV_HEIGHT - 2 - 10)
+        assert_equal(self.nodes[0].getblockcount(), CLTV_HEIGHT - 2)
 
         self.log.info("Test that invalid-according-to-CLTV transactions can still appear in a block")
 

test/functional/feature_csv_activation.py

@@ -40,6 +40,7 @@
 from itertools import product
 
 from test_framework.blocktools import (
+    CSV_ACTIVATION_HEIGHT,
     create_block,
     create_coinbase,
     TIME_GENESIS_BLOCK,
@@ -63,12 +64,12 @@
 TESTING_TX_COUNT = 83  # Number of testing transactions: 1 BIP113 tx, 16 BIP68 txs, 66 BIP112 txs (see comments above)
 COINBASE_BLOCK_COUNT = TESTING_TX_COUNT  # Number of coinbase blocks we need to generate as inputs for our txs
 BASE_RELATIVE_LOCKTIME = 10
-CSV_ACTIVATION_HEIGHT = 432
 SEQ_DISABLE_FLAG = 1 << 31
 SEQ_RANDOM_HIGH_BIT = 1 << 25
 SEQ_TYPE_FLAG = 1 << 22
 SEQ_RANDOM_LOW_BIT = 1 << 18
 
+
 def relative_locktime(sdf, srhb, stf, srlb):
     """Returns a locktime with certain bits set."""
 
@@ -83,6 +84,7 @@ def relative_locktime(sdf, srhb, stf, srlb):
         locktime |= SEQ_RANDOM_LOW_BIT
     return locktime
 
+
 def all_rlt_txs(txs):
     return [tx['tx'] for tx in txs]
 
@@ -93,6 +95,7 @@ def set_test_params(self):
         self.setup_clean_chain = True
         # Must set '-dip3params=2000:2000' to create pre-dip3 blocks only
         self.extra_args = [[
+            '-peertimeout=999999',  # bump because mocktime might cause a disconnect otherwise
             '-whitelist=noban@127.0.0.1',
             '-dip3params=2000:2000',
             '-par=1',  # Use only one script thread to get the exact reject reason for testing
@@ -148,13 +151,13 @@ def create_bip112txs(self, bip112inputs, varyOP_CSV, txversion, locktime_delta=0
         for i, (sdf, srhb, stf, srlb) in enumerate(product(*[[True, False]] * 4)):
             locktime = relative_locktime(sdf, srhb, stf, srlb)
             tx = self.create_self_transfer_from_utxo(bip112inputs[i])
-            if (varyOP_CSV):  # if varying OP_CSV, nSequence is fixed
+            if varyOP_CSV:  # if varying OP_CSV, nSequence is fixed
                 tx.vin[0].nSequence = BASE_RELATIVE_LOCKTIME + locktime_delta
             else:  # vary nSequence instead, OP_CSV is fixed
                 tx.vin[0].nSequence = locktime + locktime_delta
             tx.nVersion = txversion
             self.miniwallet.sign_tx(tx)
-            if (varyOP_CSV):
+            if varyOP_CSV:
                 tx.vin[0].scriptSig = CScript([locktime, OP_CHECKSEQUENCEVERIFY, OP_DROP] + list(CScript(tx.vin[0].scriptSig)))
             else:
                 tx.vin[0].scriptSig = CScript([BASE_RELATIVE_LOCKTIME, OP_CHECKSEQUENCEVERIFY, OP_DROP] + list(CScript(tx.vin[0].scriptSig)))
@@ -201,7 +204,7 @@ def run_test(self):
         self.tip = int(self.nodes[0].getbestblockhash(), 16)
 
         # Activation height is hardcoded
-        test_blocks = self.generate_blocks(CSV_ACTIVATION_HEIGHT-5 - COINBASE_BLOCK_COUNT)
+        test_blocks = self.generate_blocks(CSV_ACTIVATION_HEIGHT - 5 - COINBASE_BLOCK_COUNT)
         #test_blocks = self.generate_blocks(345)
         self.send_blocks(test_blocks)
         assert not softfork_active(self.nodes[0], 'csv')
@@ -487,5 +490,6 @@ def run_test(self):
         self.send_blocks([self.create_test_block(time_txs)])
         self.nodes[0].invalidateblock(self.nodes[0].getbestblockhash())
 
+
 if __name__ == '__main__':
     BIP68_112_113Test().main()

test/functional/feature_dersig.py

@@ -4,10 +4,11 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test BIP66 (DER SIG).
 
-Test that the DERSIG soft-fork activates at (regtest) height 1251.
+Test the DERSIG soft-fork activation on regtest.
 """
 
 from test_framework.blocktools import (
+    DERSIG_HEIGHT,
     create_block,
     create_coinbase,
 )
@@ -24,8 +25,6 @@
     MiniWalletMode,
 )
 
-DERSIG_HEIGHT = 1251
-
 
 # A canonical signature consists of:
 # <30> <total len> <02> <len R> <R> <02> <len S> <S> <hashtype>
@@ -88,8 +87,10 @@ def run_test(self):
         block.rehash()
         block.solve()
 
+        assert_equal(self.nodes[0].getblockcount(), DERSIG_HEIGHT - 2)
         self.test_dersig_info(is_active=False)  # Not active as of current tip and next block does not need to obey rules
         peer.send_and_ping(msg_block(block))
+        assert_equal(self.nodes[0].getblockcount(), DERSIG_HEIGHT - 1)
         self.test_dersig_info(is_active=True)  # Not active as of current tip, but next block must obey rules
         assert_equal(self.nodes[0].getbestblockhash(), block.hash)
 

test/functional/rpc_blockchain.py

@@ -27,6 +27,8 @@
 
 from test_framework.address import ADDRESS_BCRT1_P2SH_OP_TRUE
 from test_framework.blocktools import (
+    CLTV_HEIGHT,
+    DERSIG_HEIGHT,
     create_block,
     create_coinbase,
     TIME_GENESIS_BLOCK,
@@ -142,9 +144,9 @@ def _test_getblockchaininfo(self):
         assert_equal(res['prune_target_size'], 576716800)
         assert_greater_than(res['size_on_disk'], 0)
         assert_equal(res['softforks'], {
-            'bip34': {'type': 'buried', 'active': False, 'height': 500},
-            'bip66': {'type': 'buried', 'active': False, 'height': 1251},
-            'bip65': {'type': 'buried', 'active': False, 'height': 1351},
+            'bip34': {'type': 'buried', 'active': True, 'height': 2},
+            'bip66': {'type': 'buried', 'active': True, 'height': DERSIG_HEIGHT},
+            'bip65': {'type': 'buried', 'active': True, 'height': CLTV_HEIGHT},
             'bip147': { 'type': 'buried', 'active': False, 'height': 432},
             'csv': {'type': 'buried', 'active': False, 'height': 432},
             'dip0001': { 'type': 'buried', 'active': False, 'height': 2000},

test/functional/test_framework/blocktools.py

@@ -35,14 +35,21 @@
 # Coinbase transaction outputs can only be spent after this number of new blocks (network rule)
 COINBASE_MATURITY = 100
 
+# Soft-fork activation heights
+DERSIG_HEIGHT = 102  # BIP 66
+CLTV_HEIGHT = 111  # BIP 65
+CSV_ACTIVATION_HEIGHT = 432
+
 NORMAL_GBT_REQUEST_PARAMS = {"rules": []} # type: ignore[var-annotated]
 
+VERSIONBITS_LAST_OLD_BLOCK_VERSION = 4
+
 def create_block(hashprev=None, coinbase=None, ntime=None, *, version=None, tmpl=None, txlist=None, dip4_activated=False, v20_activated=False):
     """Create a block (with regtest difficulty)."""
     block = CBlock()
     if tmpl is None:
         tmpl = {}
-    block.nVersion = version or tmpl.get('version') or 1
+    block.nVersion = version or tmpl.get('version') or VERSIONBITS_LAST_OLD_BLOCK_VERSION
     block.nTime = ntime or tmpl.get('curtime') or int(time.time() + 600)
     block.hashPrevBlock = hashprev or int(tmpl['previousblockhash'], 0x10)
     if tmpl and not tmpl.get('bits') is None: