Chainparams: Introduce -con_has_parent_chain option

contrib/devtools/check-doc.py

@@ -23,7 +23,7 @@ REGEX_DOC = re.compile(r'HelpMessageOpt\(\"(\-[^\"=]+?)(?:=|\")')
 # list unsupported, deprecated and duplicate args as they need no documentation
 SET_DOC_OPTIONAL = set(['-rpcssl', '-benchmark', '-h', '-help', '-socks', '-tor', '-debugnet', '-whitelistalwaysrelay', '-prematurewitness', '-walletprematurewitness', '-promiscuousmempoolflags', '-blockminsize'])
 
-SET_DOC_OPTIONAL.update(['-con_fpowallowmindifficultyblocks', '-con_fpownoretargeting', '-con_nsubsidyhalvinginterval', '-con_bip34height', '-con_bip65height', '-con_bip66height', '-con_npowtargettimespan', '-con_npowtargetspacing', '-con_nrulechangeactivationthreshold', '-con_nminerconfirmationwindow', '-con_powlimit', '-con_parentpowlimit', '-con_bip34hash', '-con_nminimumchainwork', '-con_defaultassumevalid', '-parentgenesisblockhash', '-ndefaultport', '-npruneafterheight', '-fdefaultconsistencychecks', '-frequirestandard', '-fmineblocksondemand', '-mainchainrpccookiefile', '-testnet', '-ct_bits', '-ct_exponent', '-anyonecanspendaremine', '-fminingrequirespeers', '-fmineblocksondemand', '-con_mandatorycoinbase'])
+SET_DOC_OPTIONAL.update(['-con_fpowallowmindifficultyblocks', '-con_fpownoretargeting', '-con_nsubsidyhalvinginterval', '-con_bip34height', '-con_bip65height', '-con_bip66height', '-con_npowtargettimespan', '-con_npowtargetspacing', '-con_nrulechangeactivationthreshold', '-con_nminerconfirmationwindow', '-con_powlimit', '-con_parentpowlimit', '-con_bip34hash', '-con_nminimumchainwork', '-con_defaultassumevalid', '-parentgenesisblockhash', '-ndefaultport', '-npruneafterheight', '-fdefaultconsistencychecks', '-frequirestandard', '-fmineblocksondemand', '-mainchainrpccookiefile', '-testnet', '-ct_bits', '-ct_exponent', '-anyonecanspendaremine', '-fminingrequirespeers', '-fmineblocksondemand', '-con_mandatorycoinbase', '-con_has_parent_chain'])
 
 def main():
   used = check_output(CMD_GREP_ARGS, shell=True)

qa/rpc-tests/feature_blocksign.py

@@ -56,7 +56,9 @@ class BlockSignTest(test_framework.BitcoinTestFramework):
         signblockscript = make_signblockscript(num_nodes, required_signers, self.keys)
         self.extra_args = [[
             "-chain=blocksign",
-            # We can't validate pegins since we don't run the parent chain.
+            # We can't validate pegins since this chain doesn't have a parent chain
+            "-con_has_parent_chain=0",
+            "-parentgenesisblockhash=00",
             "-validatepegin=0",
             "-signblockscript={}".format(signblockscript)
         ]] * self.num_nodes

src/chainparams.cpp

@@ -134,6 +134,10 @@ protected:
         parentGenesisBlockHash = uint256S(GetArg("-parentgenesisblockhash", "0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206"));
         initialFreeCoins = GetArg("-initialfreecoins", 0);
         initial_reissuance_tokens = GetArg("-initialreissuancetokens", 0);
+        consensus.has_parent_chain = GetBoolArg("-con_has_parent_chain", true);
+        // Either it has a parent chain or not
+        const bool parent_genesis_is_null = parentGenesisBlockHash == uint256();
+        assert(consensus.has_parent_chain != parent_genesis_is_null);
 
         const CScript default_script(CScript() << OP_TRUE);
         consensus.signblockscript = StrHexToScriptWithDefault(GetArg("-signblockscript", ""), default_script);

src/consensus/params.h

@@ -72,6 +72,7 @@ struct Params {
     uint32_t pegin_min_depth;
     CScript mandatory_coinbase_destination;
     CScript signblockscript;
+    bool has_parent_chain;
 };
 } // namespace Consensus
 

src/validation.cpp

@@ -2442,6 +2442,11 @@ static bool CheckPeginTx(const std::vector<unsigned char>& tx_data, T& pegtx, co
 
 bool IsValidPeginWitness(const CScriptWitness& pegin_witness, const COutPoint& prevout, bool check_depth) {
 
+    // 0) Return false if !consensus.has_parent_chain
+    if (!Params().GetConsensus().has_parent_chain) {
+        return false;
+    }
+
     // Format on stack is as follows:
     // 1) value - the value of the pegin output
     // 2) asset type - the asset type being pegged in