psbt: Implement merge for Taproot fields

Author: achow101

src/psbt.cpp

@@ -194,11 +194,17 @@ void PSBTInput::Merge(const PSBTInput& input)
     hash256_preimages.insert(input.hash256_preimages.begin(), input.hash256_preimages.end());
     hd_keypaths.insert(input.hd_keypaths.begin(), input.hd_keypaths.end());
     unknown.insert(input.unknown.begin(), input.unknown.end());
+    m_tap_script_sigs.insert(input.m_tap_script_sigs.begin(), input.m_tap_script_sigs.end());
+    m_tap_scripts.insert(input.m_tap_scripts.begin(), input.m_tap_scripts.end());
+    m_tap_bip32_paths.insert(input.m_tap_bip32_paths.begin(), input.m_tap_bip32_paths.end());
 
     if (redeem_script.empty() && !input.redeem_script.empty()) redeem_script = input.redeem_script;
     if (witness_script.empty() && !input.witness_script.empty()) witness_script = input.witness_script;
     if (final_script_sig.empty() && !input.final_script_sig.empty()) final_script_sig = input.final_script_sig;
     if (final_script_witness.IsNull() && !input.final_script_witness.IsNull()) final_script_witness = input.final_script_witness;
+    if (m_tap_key_sig.empty() && !input.m_tap_key_sig.empty()) m_tap_key_sig = input.m_tap_key_sig;
+    if (m_tap_internal_key.IsNull() && !input.m_tap_internal_key.IsNull()) m_tap_internal_key = input.m_tap_internal_key;
+    if (m_tap_merkle_root.IsNull() && !input.m_tap_merkle_root.IsNull()) m_tap_merkle_root = input.m_tap_merkle_root;
 }
 
 void PSBTOutput::FillSignatureData(SignatureData& sigdata) const
@@ -254,9 +260,12 @@ void PSBTOutput::Merge(const PSBTOutput& output)
 {
     hd_keypaths.insert(output.hd_keypaths.begin(), output.hd_keypaths.end());
     unknown.insert(output.unknown.begin(), output.unknown.end());
+    m_tap_bip32_paths.insert(output.m_tap_bip32_paths.begin(), output.m_tap_bip32_paths.end());
 
     if (redeem_script.empty() && !output.redeem_script.empty()) redeem_script = output.redeem_script;
     if (witness_script.empty() && !output.witness_script.empty()) witness_script = output.witness_script;
+    if (m_tap_internal_key.IsNull() && !output.m_tap_internal_key.IsNull()) m_tap_internal_key = output.m_tap_internal_key;
+    if (m_tap_tree.has_value() && !output.m_tap_tree.has_value()) m_tap_tree = output.m_tap_tree;
 }
 bool PSBTInputSigned(const PSBTInput& input)
 {