From e9bfff25db60129fe7dfc7a1aaea82c6b80a4491 Mon Sep 17 00:00:00 2001
From: Andrew Chow <achow101-github@achow101.com>
Date: Fri, 16 Apr 2021 16:00:08 -0400
Subject: [PATCH] Allow empty scriptPubKeys

---
 src/blindpsbt.cpp               |  2 +-
 src/psbt.cpp                    |  6 +++---
 src/psbt.h                      | 12 +++++++-----
 src/qt/psbtoperationsdialog.cpp |  2 +-
 src/rpc/rawtransaction.cpp      |  4 ++--
 src/wallet/scriptpubkeyman.cpp  |  2 +-
 6 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/src/blindpsbt.cpp b/src/blindpsbt.cpp
index 55ad807710..2ffc897810 100644
--- a/src/blindpsbt.cpp
+++ b/src/blindpsbt.cpp
@@ -393,7 +393,7 @@ BlindingStatus BlindPSBT(PartiallySignedTransaction& psbt, std::map<uint32_t, st
         uint256 nonce = GenerateRangeproofECDHKey(ecdh_key, output.m_blinding_pubkey);
 
         // Generate rangeproof
-        bool rangeresult = CreateValueRangeProof(rangeproof, value_blinder, nonce, *output.amount, output.script, value_commit, asset_generator, asset, asset_blinder);
+        bool rangeresult = CreateValueRangeProof(rangeproof, value_blinder, nonce, *output.amount, *output.script, value_commit, asset_generator, asset, asset_blinder);
         assert(rangeresult);
 
         // Create surjection proof for this output
diff --git a/src/psbt.cpp b/src/psbt.cpp
index 42950f24ff..4a19941907 100644
--- a/src/psbt.cpp
+++ b/src/psbt.cpp
@@ -121,7 +121,7 @@ CMutableTransaction PartiallySignedTransaction::GetUnsignedTx() const
     for (const PSBTOutput& output : outputs) {
         CTxOut txout;
         txout.nValue = *output.amount;
-        txout.scriptPubKey = output.script;
+        txout.scriptPubKey = *output.script;
         mtx.vout.push_back(txout);
     }
     return mtx;
@@ -232,13 +232,13 @@ bool PartiallySignedTransaction::AddInput(PSBTInput& psbtin)
 
 bool PartiallySignedTransaction::AddOutput(const PSBTOutput& psbtout)
 {
-    if (psbtout.amount == nullopt || psbtout.script.empty()) {
+    if (psbtout.amount == nullopt || psbtout.script == nullopt) {
         return false;
     }
 
     if (tx != nullopt) {
         // This is a v0 psbt, do the v0 AddOutput
-        CTxOut txout(CAsset(), *psbtout.amount, psbtout.script);
+        CTxOut txout(CAsset(), *psbtout.amount, *psbtout.script);
         tx->vout.push_back(txout);
         outputs.push_back(psbtout);
         return true;
diff --git a/src/psbt.h b/src/psbt.h
index b81a785042..826d8dd05a 100644
--- a/src/psbt.h
+++ b/src/psbt.h
@@ -904,7 +904,7 @@ struct PSBTOutput
     CScript witness_script;
     std::map<CPubKey, KeyOriginInfo> hd_keypaths;
     Optional<CAmount> amount;
-    CScript script;
+    Optional<CScript> script;
     std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
     std::set<PSBTProprietary> m_proprietary;
 
@@ -948,9 +948,9 @@ struct PSBTOutput
 
         if (m_psbt_version >= 2) {
             // Write spk
-            if (!script.empty()) {
+            if (script != nullopt) {
                 SerializeToVector(s, CompactSizeWriter(PSBT_OUT_SCRIPT));
-                s << script;
+                s << *script;
             }
 
             // Elements proprietary fields are v2 only
@@ -1090,7 +1090,9 @@ struct PSBTOutput
                     } else if (key.size() != 1) {
                         throw std::ios_base::failure("Output script key is more than one byte type");
                     }
-                    s >> script;
+                    CScript sc;
+                    s >> sc;
+                    script = sc;
                     break;
                 }
                 case PSBT_OUT_PROPRIETARY:
@@ -1224,7 +1226,7 @@ struct PSBTOutput
             if (amount == nullopt) {
                 throw std::ios_base::failure("Output amount is required in PSBTv2");
             }
-            if (script.empty()) {
+            if (script == nullopt) {
                 throw std::ios_base::failure("Output script is required in PSBTv2");
             }
         }
diff --git a/src/qt/psbtoperationsdialog.cpp b/src/qt/psbtoperationsdialog.cpp
index 96c97a9c2d..bd15657b40 100644
--- a/src/qt/psbtoperationsdialog.cpp
+++ b/src/qt/psbtoperationsdialog.cpp
@@ -163,7 +163,7 @@ std::string PSBTOperationsDialog::renderTransaction(const PartiallySignedTransac
     int unit = m_client_model->getOptionsModel()->getDisplayUnit();
     for (const PSBTOutput& out : psbtx.outputs) {
         CTxDestination address;
-        ExtractDestination(out.script, address);
+        ExtractDestination(*out.script, address);
         totalAmount += *out.amount;
         tx_description.append(tr(" * Sends %1 to %2")
             .arg(BitcoinUnits::formatWithUnit(BitcoinUnits::BTC, *out.amount))
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 2c93b51fc6..523bb3ef89 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -1719,9 +1719,9 @@ static RPCHelpMan decodepsbt()
             if (output.amount != nullopt) {
                 out.pushKV("amount", ValueFromAmount(*output.amount));
             }
-            if (!output.script.empty()) {
+            if (output.script != nullopt) {
                 UniValue spk(UniValue::VOBJ);
-                ScriptPubKeyToUniv(output.script, spk, true);
+                ScriptPubKeyToUniv(*output.script, spk, true);
                 out.pushKV("script", spk);
             }
         }
diff --git a/src/wallet/scriptpubkeyman.cpp b/src/wallet/scriptpubkeyman.cpp
index b3e07976a3..099ab12ee3 100644
--- a/src/wallet/scriptpubkeyman.cpp
+++ b/src/wallet/scriptpubkeyman.cpp
@@ -2150,7 +2150,7 @@ TransactionError DescriptorScriptPubKeyMan::FillPSBT(PartiallySignedTransaction&
 
     // Fill in the bip32 keypaths and redeemscripts for the outputs so that hardware wallets can identify change
     for (unsigned int i = 0; i < psbtx.outputs.size(); ++i) {
-        std::unique_ptr<SigningProvider> keys = GetSolvingProvider(psbtx.outputs.at(i).script);
+        std::unique_ptr<SigningProvider> keys = GetSolvingProvider(*psbtx.outputs.at(i).script);
         if (!keys) {
             continue;
         }