Merge 2aff9a36c3 into merged_master (Bitcoin PR bitcoin/bitcoin#30352)

src/script/interpreter.cpp

@@ -3313,6 +3313,8 @@ static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion,
             }
             return set_success(serror);
         }
+    } else if (!is_p2sh && CScript::IsPayToAnchor(witversion, program)) {
+        return true;
     } else {
         if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM) {
             return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM);

src/script/script.cpp

@@ -318,6 +318,23 @@ bool CScript::IsPayToWitnessPubkeyHash() const
 // END ELEMENTS
 //
 
+bool CScript::IsPayToAnchor() const
+{
+    return (this->size() == 4 &&
+        (*this)[0] == OP_1 &&
+        (*this)[1] == 0x02 &&
+        (*this)[2] == 0x4e &&
+        (*this)[3] == 0x73);
+}
+
+bool CScript::IsPayToAnchor(int version, const std::vector<unsigned char>& program)
+{
+    return version == 1 &&
+        program.size() == 2 &&
+        program[0] == 0x4e &&
+        program[1] == 0x73;
+}
+
 bool CScript::IsPayToScriptHash() const
 {
     // Extra-fast test for pay-to-script-hash CScripts:

src/script/script.h

@@ -597,6 +597,14 @@ public:
 
     bool IsPayToPubkeyHash() const;
     bool IsPayToWitnessPubkeyHash() const;
+    /*
+     * OP_1 <0x4e73>
+     */
+    bool IsPayToAnchor() const;
+    /** Checks if output of IsWitnessProgram comes from a P2A output script
+     */
+    static bool IsPayToAnchor(int version, const std::vector<unsigned char>& program);
+
     bool IsPayToScriptHash() const;
     bool IsPayToWitnessScriptHash() const;
     bool IsWitnessProgram(int& version, std::vector<unsigned char>& program) const;

src/script/sign.cpp

@@ -484,10 +484,10 @@ static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator
     // ELEMENTS
     case TxoutType::FEE:
         return false;
-
     case TxoutType::OP_TRUE:
         return Params().anyonecanspend_aremine;
-
+    case TxoutType::ANCHOR:
+        return true;
     } // no default case, so the compiler can warn about missing cases
     assert(false);
 }

src/script/solver.cpp

@@ -25,6 +25,7 @@ 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 "anchor";
     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";
@@ -179,6 +180,9 @@ TxoutType Solver(const CScript& scriptPubKey, std::vector<std::vector<unsigned c
             vSolutionsRet.push_back(std::move(witnessprogram));
             return TxoutType::WITNESS_V1_TAPROOT;
         }
+        if (scriptPubKey.IsPayToAnchor()) {
+            return TxoutType::ANCHOR;
+        }
         if (witnessversion != 0) {
             vSolutionsRet.push_back(std::vector<unsigned char>{(unsigned char)witnessversion});
             vSolutionsRet.push_back(std::move(witnessprogram));

src/script/solver.h

@@ -22,6 +22,7 @@ template <typename C> class Span;
 enum class TxoutType {
     NONSTANDARD,
     // 'standard' transaction types:
+    ANCHOR, //!< anyone can spend script
     PUBKEY,
     PUBKEYHASH,
     SCRIPTHASH,