Please help me see if the bitcoin output for this asset transaction is normal.

[SevenLiquor]

A strange phenomenon occurred when I made an asset transfer. I am not sure if this is normal.
Normally a normal transfer would have two 1000sat bitcoin outputs to anchor the asset. There will also be one bitcoin output back to my own address. But this transaction seems to be mixing the 1000sat to the other party with the output back to my own address.

This is a bitcoin transaction：

{
  "txid": "273feebe085b17de39408b1fba984d9301b94b99965fcbf5c8f7a32c3230a644",
  "hash": "3cf342c701295180bcc9bf16b2cb3b9b1f4bc7f578ae19b207084ea69ffb1a60",
  "version": 2,
  "size": 419,
  "vsize": 269,
  "weight": 1076,
  "locktime": 0,
  "vin": [
    {
      "txid": "b5c8169b19cb166a0af3f745ef18a1e3d99fec2e6ce6b76e61e5a0aa3080a7f1",
      "vout": 2,
      "scriptSig": {
        "asm": "",
        "hex": ""
      },
      "txinwitness": [
        "dbefefdd48be219e4151b711bc005437da8c7f0937f03a78a005bd5a15e05571b78fb589f3d3851e00b992f9f80a6d64e9fda5636fc467bbe76221369cd3052a"
      ],
      "sequence": 4294967295
    },
    {
      "txid": "d55957463bf469ba7b1e8ea50f4094f1e4fcc77deaaca075da63b995c2ed712b",
      "vout": 2,
      "scriptSig": {
        "asm": "",
        "hex": ""
      },
      "txinwitness": [
        "ef8f30166ee75418c36f32a737f9f4e368b4e7c276d0959b6edee5d97a922549ae7b10aec874229ac112ed81163c8b6832b849363da7f767571a57d92427e412"
      ],
      "sequence": 4294967295
    },
    {
      "txid": "7e7c00c280559028b25db3cc061d2c74f8fe899a89d2c6640f028d83a8069e32",
      "vout": 0,
      "scriptSig": {
        "asm": "",
        "hex": ""
      },
      "txinwitness": [
        "0eafb4ef1b93910fe685eb34bee08c2457f2fa663c99c574c0c09b8ab75edf8d3e470cd785693f5ba05b3f9b23a6e663edbcd6e71d09cded13928fcac4c4e79a"
      ],
      "sequence": 0
    }
  ],
  "vout": [
    {
      "value": 0.00001000,
      "n": 0,
      "scriptPubKey": {
        "asm": "1 068fab1446358f34de2efb8c797d55f295fb6f457b0c2a17c1a54dca3b92db83",
        "desc": "rawtr(068fab1446358f34de2efb8c797d55f295fb6f457b0c2a17c1a54dca3b92db83)#nyjpqcsu",
        "hex": "5120068fab1446358f34de2efb8c797d55f295fb6f457b0c2a17c1a54dca3b92db83",
        "address": "bc1pq686k9zxxk8nfh3wlwx8jl24722lkm690vxz597p54xu5wujmwpsj8a556",
        "type": "witness_v1_taproot"
      }
    },
    {
      "value": 0.00002167,
      "n": 1,
      "scriptPubKey": {
        "asm": "1 59a4163bd5b8f37980eef995ba673edac7cf979d1e3f3a5191aeaeda1df7bb3a",
        "desc": "rawtr(59a4163bd5b8f37980eef995ba673edac7cf979d1e3f3a5191aeaeda1df7bb3a)#8mrzf8lv",
        "hex": "512059a4163bd5b8f37980eef995ba673edac7cf979d1e3f3a5191aeaeda1df7bb3a",
        "address": "bc1ptxjpvw74hrehnq8wlx2m5ee7mtrul9uarcln55v346hd580hhvaqsw9nmg",
        "type": "witness_v1_taproot"
      }
    }
  ]
}

This` is a proof of assets with an output of 2167sat：

{
    "asset": {
        "version": "ASSET_VERSION_V0",
        "asset_genesis": {
            "genesis_point": "9aac0f8149ef38f6af5ed809476350dabae89801699d17ebbfc821c6f17d0db7:2",
            "name": "Phenix",
            "meta_hash": "dd70742abe7006267a53178b6c42c42207bdc7f7483432dc62236119b1152dba",
            "asset_id": "47ed120d4b173eb79ba46cd1959bb9c881cb69332cf8a21336110bda05402308",
            "asset_type": "NORMAL",
            "output_index": 0,
            "version": 0
        },
        "amount": "10000",
        "lock_time": 0,
        "relative_lock_time": 0,
        "script_version": 0,
        "script_key": "02d938c31d88917f89bf007f91363e7a0fc7732fbee653cef4faefe6f3e1b11a47",
        "script_key_is_local": false,
        "asset_group": null,
        "chain_anchor": null,
        "prev_witnesses": [
            {
                "prev_id": {
                    "anchor_point": "0000000000000000000000000000000000000000000000000000000000000000:0",
                    "asset_id": "0000000000000000000000000000000000000000000000000000000000000000",
                    "script_key": "000000000000000000000000000000000000000000000000000000000000000000",
                    "amount": "0"
                },
                "tx_witness": [],
                "split_commitment": {
                    "root_asset": {
                        "version": "ASSET_VERSION_V0",
                        "asset_genesis": {
                            "genesis_point": "9aac0f8149ef38f6af5ed809476350dabae89801699d17ebbfc821c6f17d0db7:2",
                            "name": "Phenix",
                            "meta_hash": "dd70742abe7006267a53178b6c42c42207bdc7f7483432dc62236119b1152dba",
                            "asset_id": "47ed120d4b173eb79ba46cd1959bb9c881cb69332cf8a21336110bda05402308",
                            "asset_type": "NORMAL",
                            "output_index": 0,
                            "version": 0
                        },
                        "amount": "39995",
                        "lock_time": 0,
                        "relative_lock_time": 0,
                        "script_version": 0,
                        "script_key": "0291b8b9e49b57601ef100862be91450dbc7301d5e7da8841ee650f3c659b71bcc",
                        "script_key_is_local": false,
                        "asset_group": null,
                        "chain_anchor": null,
                        "prev_witnesses": [
                            {
                                "prev_id": {
                                    "anchor_point": "7e7c00c280559028b25db3cc061d2c74f8fe899a89d2c6640f028d83a8069e32:0",
                                    "asset_id": "47ed120d4b173eb79ba46cd1959bb9c881cb69332cf8a21336110bda05402308",
                                    "script_key": "020521f6d7f007a8adf3c5981f5029d27fe6c3dd48a4ce2ec378188f11c590128f",
                                    "amount": "0"
                                },
                                "tx_witness": [
                                    "c65a2c5e996f9a566945965e25261d94d18d893f3d8745d80a47f4a794be555410275d15ea90d72660eab72e907210fe09834f11fbe0425ecd7e902bcb38a552"
                                ],
                                "split_commitment": null
                            }
                        ],
                        "is_spent": false,
                        "lease_owner": "",
                        "lease_expiry": "0",
                        "is_burn": false
                    }
                }
            }
        ],
        "is_spent": false,
        "lease_owner": "",
        "lease_expiry": "0",
        "is_burn": false
    },
    "proof": "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"
}

thanks~!

[guggero]

Thanks for the proof, I was able to confirm there are assets in both outputs, index 0 and 1.
What version of tapd did you do this transfer with? And how did you initiate it? Over the command line or using RPC calls?

[guggero]

The transfer uses RPC calls.

Can you go into more details on this? If you're not simply using tapcli assets send then you can customize the BTC amount being used. So it really depends on how you call the RPCs.

[SevenLiquor]

OH, I think I just simply used rpc from the code.
This is the rpc code I called.

func sendAssets(addrs []string, feeRate uint32) (*taprpc.SendAssetResponse, error) {
	conn, clearUp, err := apiConnect.GetConnection("tapd", false)
	if err != nil {
		fmt.Printf("%s did not connect: %v\n", GetTimeNow(), err)
	}
	defer clearUp()
	client := taprpc.NewTaprootAssetsClient(conn)

	request := &taprpc.SendAssetRequest{
		TapAddrs: addrs,
	}
	if feeRate > 0 {
		request.FeeRate = feeRate
	}
	response, err := client.SendAsset(context.Background(), request)
	if err != nil {
		fmt.Printf("%s taprpc SendAsset Error: %v\n", GetTimeNow(), err)
		return nil, err
	}
	return response, nil
}

I simply called this code. Passed in an address and a fee.

[guggero]

Ah, okay. This is basically the same as tapcli assets send does, so it should behave as you expected. I'll take a look why this wouldn't create 3 outputs. My current assumption is that due to the fee rate there weren't enough funds left to create a third output, so things were grouped together. But I'll confirm by looking into the code.

[guggero]

Okay, I looked at the v0.3.3 code and I think you hit an edge case where the lnd's FundPsbt wouldn't add a change output because the value left over would've been too small. And then the send logic just used the second output to commit the assets to.
The whole send logic and fee estimation has been completely overhauled in the upcoming v0.4.0, so this might no longer be happening.
But in any case, this shouldn't be an issue when attempting to further send the assets, everything should be accounted for properly.

So to answer your question: It's kind of normal since the on-chain BTC input amount was just very small and not enough to create a BTC-only change output, therefore the asset change and BTC change were combined.

[SevenLiquor]

Thank you very much for your answer.