Change PSBT::AddInput to take just PSBTInput

src/psbt.cpp

@@ -125,17 +125,36 @@ uint256 PartiallySignedTransaction::GetUniqueID() const
     return mtx.GetHash();
 }
 
-bool PartiallySignedTransaction::AddInput(const CTxIn& txin, PSBTInput& psbtin)
+bool PartiallySignedTransaction::AddInput(PSBTInput& psbtin)
 {
-    if (std::find(tx->vin.begin(), tx->vin.end(), txin) != tx->vin.end()) {
-        return false;
+    if (m_version == std::nullopt || m_version == 0) {
+        // This is a v0 psbt, so do the v0 AddInput
+        CTxIn txin(COutPoint(psbtin.prev_txid, *psbtin.prev_out));
+        if (std::find(tx->vin.begin(), tx->vin.end(), txin) != tx->vin.end()) {
+            // Prevent duplicate inputs
+            return false;
+        }
+        tx->vin.push_back(txin);
+        psbtin.partial_sigs.clear();
+        psbtin.final_script_sig.clear();
+        psbtin.final_script_witness.SetNull();
+        inputs.push_back(psbtin);
+        return true;
     }
-    tx->vin.push_back(txin);
-    psbtin.partial_sigs.clear();
-    psbtin.final_script_sig.clear();
-    psbtin.final_script_witness.SetNull();
-    inputs.push_back(psbtin);
-    return true;
+
+    if (m_version >= 2) {
+        // Prevent duplicate inputs
+        if (std::find_if(inputs.begin(), inputs.end(),
+            [psbtin](const PSBTInput& psbt) {
+                return psbt.prev_txid == psbtin.prev_txid && psbt.prev_out == psbtin.prev_out;
+            }
+        ) != inputs.end()) {
+            return false;
+        }
+    }
+
+    // TODO: Do PSBTv2
+    Assert(false);
 }
 
 bool PartiallySignedTransaction::AddOutput(const CTxOut& txout, const PSBTOutput& psbtout)

src/psbt.h

@@ -1323,7 +1323,7 @@ struct PartiallySignedTransaction
     /** Merge psbt into this. The two psbts must have the same underlying CTransaction (i.e. the
       * same actual Bitcoin transaction.) Returns true if the merge succeeded, false otherwise. */
     [[nodiscard]] bool Merge(const PartiallySignedTransaction& psbt);
-    bool AddInput(const CTxIn& txin, PSBTInput& psbtin);
+    bool AddInput(PSBTInput& psbtin);
     bool AddOutput(const CTxOut& txout, const PSBTOutput& psbtout);
     void SetupFromTx(const CMutableTransaction& tx);
     void CacheUnsignedTxPieces();

src/rpc/rawtransaction.cpp

@@ -1860,7 +1860,7 @@ static RPCHelpMan joinpsbts()
     // Merge
     for (auto& psbt : psbtxs) {
         for (unsigned int i = 0; i < psbt.tx->vin.size(); ++i) {
-            if (!merged_psbt.AddInput(psbt.tx->vin[i], psbt.inputs[i])) {
+            if (!merged_psbt.AddInput(psbt.inputs[i])) {
                 throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Input %s:%d exists in multiple PSBTs", psbt.tx->vin[i].prevout.hash.ToString(), psbt.tx->vin[i].prevout.n));
             }
         }
@@ -1892,7 +1892,7 @@ static RPCHelpMan joinpsbts()
     shuffled_psbt.tx->version = merged_psbt.tx->version;
     shuffled_psbt.tx->nLockTime = merged_psbt.tx->nLockTime;
     for (int i : input_indices) {
-        shuffled_psbt.AddInput(merged_psbt.tx->vin[i], merged_psbt.inputs[i]);
+        shuffled_psbt.AddInput(merged_psbt.inputs[i]);
     }
     for (int i : output_indices) {
         shuffled_psbt.AddOutput(merged_psbt.tx->vout[i], merged_psbt.outputs[i]);

src/test/fuzz/psbt.cpp

@@ -84,8 +84,8 @@ FUZZ_TARGET(psbt)
     psbt_mut = psbt;
     (void)CombinePSBTs(psbt_mut, {psbt_mut, psbt_merge});
     psbt_mut = psbt;
-    for (unsigned int i = 0; i < psbt_merge.tx->vin.size(); ++i) {
-        (void)psbt_mut.AddInput(psbt_merge.tx->vin[i], psbt_merge.inputs[i]);
+    for (auto& psbt_in : psbt_merge.inputs) {
+        (void)psbt_mut.AddInput(psbt_in);
     }
     for (unsigned int i = 0; i < psbt_merge.tx->vout.size(); ++i) {
         Assert(psbt_mut.AddOutput(psbt_merge.tx->vout[i], psbt_merge.outputs[i]));