Merge psbt peg-in data

Author: achow101

src/psbt.cpp

@@ -159,6 +159,11 @@ void PSBTInput::Merge(const PSBTInput& input)
     if (value_blinding_factor.IsNull() && !input.value_blinding_factor.IsNull()) value_blinding_factor = input.value_blinding_factor;
     if (asset.IsNull() && !input.asset.IsNull()) asset = input.asset;
     if (asset_blinding_factor.IsNull() && !input.asset_blinding_factor.IsNull()) asset_blinding_factor = input.asset_blinding_factor;
+
+    if (peg_in_tx.which() == 0 && peg_in_tx.which() > 0) peg_in_tx = input.peg_in_tx;
+    if (txout_proof.which() == 0 && peg_in_tx.which() > 0) txout_proof = input.txout_proof;
+    if (claim_script.empty() && !input.claim_script.empty()) claim_script = input.claim_script;
+    if (genesis_hash.IsNull() && !input.genesis_hash.IsNull()) genesis_hash = input.genesis_hash;
 }
 
 bool PSBTInput::IsSane() const

test/functional/feature_fedpeg.py

@@ -302,6 +302,15 @@ def run_test(self):
         assert_equal(decoded_psbt['inputs'][0]['pegin_claim_script'], addrs["claim_script"])
         assert_equal(decoded_psbt['inputs'][0]['pegin_txout_proof'], proof)
         assert_equal(decoded_psbt['inputs'][0]['pegin_genesis_hash'], parent.getblockhash(0))
+        # Make a psbt without those peg-in data and merge them
+        merge_pegin_psbt = sidechain.createpsbt([{"txid":txid1, "vout": vout}], outputs)
+        decoded_psbt = sidechain.decodepsbt(merge_pegin_psbt)
+        assert 'pegin_bitcoin_tx' not in decoded_psbt['inputs'][0]
+        assert 'pegin_claim_script' not in decoded_psbt['inputs'][0]
+        assert 'pegin_txout_proof' not in decoded_psbt['inputs'][0]
+        assert 'pegin_genesis_hash' not in decoded_psbt['inputs'][0]
+        merged_pegin_psbt = sidechain.combinepsbt([pegin_psbt, merge_pegin_psbt])
+        assert_equal(pegin_psbt, merged_pegin_psbt)
 
         sample_pegin_struct = FromHex(CTransaction(), signed_pegin["hex"])
         # Round-trip peg-in transaction using python serialization