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: