rpc: populate minting batch txid, add test assertion

Author: Roasbeef

itest/utils.go

@@ -276,5 +276,18 @@ func MintAssetsConfirmBatch(t *testing.T, minerClient *rpcclient.Client,
 		mintrpc.BatchState_BATCH_STATE_FINALIZED,
 	)
 
+	// We should be able to fetch the batch, and also find that the txid of
+	// the batch tx is populated.
+	batchResp, err := tapClient.ListBatches(ctxt, &mintrpc.ListBatchRequest{
+		Filter: &mintrpc.ListBatchRequest_BatchKey{
+			BatchKey: batchKey,
+		},
+	})
+	require.NoError(t, err)
+	require.Len(t, batchResp.Batches, 1)
+
+	batch := batchResp.Batches[0]
+	require.NotEmpty(t, batch.BatchTxid)
+
 	return AssertAssetsMinted(t, tapClient, assetRequests, mintTXID, blockHash)
 }

rpcserver.go

@@ -17,6 +17,7 @@ import (
 
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcec/v2/schnorr"
+	"github.com/btcsuite/btcd/btcutil/psbt"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/davecgh/go-spew/spew"
@@ -2321,6 +2322,18 @@ func marshalMintingBatch(batch *tapgarden.MintingBatch,
 		State:    rpcBatchState,
 	}
 
+	// If we have the genesis packet available (funded+signed), then we'll
+	// display the txid as well.
+	if batch.GenesisPacket != nil {
+		batchTx, err := psbt.Extract(batch.GenesisPacket.Pkt)
+		if err == nil {
+			rpcBatch.BatchTxid = batchTx.TxHash().String()
+		} else {
+			rpcsLog.Errorf("unable to extract batch tx: %v", err)
+		}
+
+	}
+
 	// If we don't need to include the seedlings, we can return here.
 	if skipSeedlings {
 		return rpcBatch, nil