[POLICY] Add OP_TRUE as a standard output type

This will be used in following commits
as the flag for ephemeral anchors, allowing
dust values, but also requiring
the output to be spend in the same relay package.

Author: instagibbs

src/rpc/rawtransaction.cpp

@@ -422,6 +422,7 @@ static RPCHelpMan decodescript()
         case TxoutType::WITNESS_V1_TAPROOT:
         // don't wrap CTV because P2SH CTV is a hash cycle
         case TxoutType::TX_BARE_DEFAULT_CHECK_TEMPLATE_VERIFY_HASH:
+        case TxoutType::ANCHOR:
             // Should not be wrapped
             return false;
         } // no default case, so the compiler can warn about missing cases
@@ -466,6 +467,7 @@ static RPCHelpMan decodescript()
             case TxoutType::WITNESS_V1_TAPROOT:
             // don't wrap CTV because P2SH CTV is a hash cycle
             case TxoutType::TX_BARE_DEFAULT_CHECK_TEMPLATE_VERIFY_HASH:
+            case TxoutType::ANCHOR:
                 // Should not be wrapped
                 return false;
             } // no default case, so the compiler can warn about missing cases

src/script/script.cpp

@@ -198,13 +198,19 @@ unsigned int CScript::GetSigOpCount(const CScript& scriptSig) const
     return subscript.GetSigOpCount(true);
 }
 
+bool CScript::IsTrue() const
+{
+    return (this->size() == 1 && (*this)[0] == OP_TRUE);
+}
+
 bool CScript::IsPayToBareDefaultCheckTemplateVerifyHash() const
 {
     // Extra-fast test for pay-to-bare-default-check-template-verify-hash CScripts:
     return (this->size() == 34 &&
             (*this)[0] == 0x20 &&
             (*this)[33] == OP_CHECKTEMPLATEVERIFY);
 }
+
 bool CScript::IsPayToScriptHash() const
 {
     // Extra-fast test for pay-to-script-hash CScripts:

src/script/script.h

@@ -532,6 +532,12 @@ class CScript : public CScriptBase
     unsigned int GetSigOpCount(const CScript& scriptSig) const;
 
     bool IsPayToBareDefaultCheckTemplateVerifyHash() const;
+
+    /*
+     * OP_TRUE
+     */
+    bool IsTrue() const;
+
     bool IsPayToScriptHash() const;
     bool IsPayToWitnessScriptHash() const;
     bool IsWitnessProgram(int& version, std::vector<unsigned char>& program) const;

src/script/sign.cpp

@@ -297,6 +297,7 @@ static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator
     case TxoutType::NULL_DATA:
     case TxoutType::WITNESS_UNKNOWN:
     case TxoutType::TX_BARE_DEFAULT_CHECK_TEMPLATE_VERIFY_HASH:
+    case TxoutType::ANCHOR:
         return false;
     case TxoutType::PUBKEY:
         if (!CreateSig(creator, sigdata, provider, sig, CPubKey(vSolutions[0]), scriptPubKey, sigversion)) return false;

src/script/standard.cpp

@@ -52,6 +52,7 @@ std::string GetTxnOutputType(TxoutType t)
     case TxoutType::SCRIPTHASH: return "scripthash";
     case TxoutType::MULTISIG: return "multisig";
     case TxoutType::NULL_DATA: return "nulldata";
+    case TxoutType::ANCHOR: return "true";
     case TxoutType::WITNESS_V0_KEYHASH: return "witness_v0_keyhash";
     case TxoutType::WITNESS_V0_SCRIPTHASH: return "witness_v0_scripthash";
     case TxoutType::WITNESS_V1_TAPROOT: return "witness_v1_taproot";
@@ -177,6 +178,8 @@ TxoutType Solver(const CScript& scriptPubKey, std::vector<std::vector<unsigned c
         std::vector<unsigned char> hashBytes(scriptPubKey.begin()+2, scriptPubKey.begin()+22);
         vSolutionsRet.push_back(hashBytes);
         return TxoutType::SCRIPTHASH;
+    } else if (scriptPubKey.IsTrue()) {
+        return TxoutType::ANCHOR;
     }
 
     if (scriptPubKey.IsPayToBareDefaultCheckTemplateVerifyHash()) {
@@ -291,6 +294,7 @@ bool ExtractDestination(const CScript& scriptPubKey, CTxDestination& addressRet)
     case TxoutType::NULL_DATA:
     case TxoutType::TX_BARE_DEFAULT_CHECK_TEMPLATE_VERIFY_HASH:
     case TxoutType::NONSTANDARD:
+    case TxoutType::ANCHOR:
         return false;
     } // no default case, so the compiler can warn about missing cases
     assert(false);

src/script/standard.h

@@ -51,6 +51,7 @@ static const unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH;
 enum class TxoutType {
     NONSTANDARD,
     // 'standard' transaction types:
+    ANCHOR, //!< anyonecanspendable script
     PUBKEY,
     PUBKEYHASH,
     SCRIPTHASH,

src/test/transaction_tests.cpp

@@ -781,7 +781,7 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
     CheckIsStandard(t);
     g_dust = CFeeRate{DUST_RELAY_TX_FEE};
 
-    t.vout[0].scriptPubKey = CScript() << OP_1;
+    t.vout[0].scriptPubKey = CScript() << OP_2;
     CheckIsNotStandard(t, "scriptpubkey");
 
     // MAX_OP_RETURN_RELAY-byte TxoutType::NULL_DATA (standard)

src/wallet/rpc/backup.cpp

@@ -911,6 +911,7 @@ static std::string RecurseImportData(const CScript& script, ImportData& import_d
     case TxoutType::NONSTANDARD:
     case TxoutType::WITNESS_UNKNOWN:
     case TxoutType::WITNESS_V1_TAPROOT:
+    case TxoutType::ANCHOR:
         return "unrecognized script";
     case TxoutType::TX_BARE_DEFAULT_CHECK_TEMPLATE_VERIFY_HASH:
         return "bare default CheckTemplateVerify hash";

src/wallet/scriptpubkeyman.cpp

@@ -104,6 +104,7 @@ IsMineResult IsMineInner(const LegacyScriptPubKeyMan& keystore, const CScript& s
     case TxoutType::NULL_DATA:
     case TxoutType::WITNESS_UNKNOWN:
     case TxoutType::WITNESS_V1_TAPROOT:
+    case TxoutType::ANCHOR:
         break;
     case TxoutType::PUBKEY:
         keyID = CPubKey(vSolutions[0]).GetID();

test/functional/feature_cltv.py

@@ -101,7 +101,7 @@ def test_cltv_info(self, *, is_active):
 
     def run_test(self):
         peer = self.nodes[0].add_p2p_connection(P2PInterface())
-        wallet = MiniWallet(self.nodes[0], mode=MiniWalletMode.RAW_OP_TRUE)
+        wallet = MiniWallet(self.nodes[0], mode=MiniWalletMode.RAW_OP_2)
 
         self.test_cltv_info(is_active=False)