In regtest mode with bitcoind backend, wallet does not pick up coinbase outputs

[GambolingPangolin]

Setup

• Start a regtest node
• Start sparrow with -n regtest and configure it to connect to the node we just started
• Create a P2WPKH wallet with private keys
• Run bitcoin-cli -regtest generatetoaddress 110 $sparrow_address

Expected behavior

110 new UTXOs should appear in the wallet, with 10 spendable and 100 in a mined, but unspendable state.

Actual behavior

No transactions show up in the wallet. This may also occur on mainnet. I don't have a way to check.

System information

• Sparrow 1.5.1
• Bitcoin Core 22.0
• Ubuntu 20.04

[craigraw]

Did you try a wallet refresh (View menu)?

Sparrow uses BWT to connect to Bitcoin Core, which may not function in the way you are expecting for this use case. @shesek would be able to say more.

[GambolingPangolin]

Did you try a wallet refresh (View menu)?

I'm afraid so. I also tried closing and reopening the application.

[shesek]

BWT does not currently support coinbase outputs, the indexer skips over them.

Adding support for indexing mature coinbase outputs should be straightforward, but immature ones requires some more thought. The Electrum RPC protocol doesn't have a way to specify whether an output is mature or not (i.e. in listunspent), so I'm not sure if/how it should be included there. For the BWT HTTP API I could add a new field to indicate this.

In addition, the wallet software will need to recognize coinbase outputs and avoid using them for coin selection until they're matured. @craigraw Would Sparrow handle this correctly?

(I created bwt-dev/bwt#93 to keep track of this.)

[craigraw]

The Electrum RPC protocol doesn't have a way to specify whether an output is mature or not

Agreed - I think that the maturity of the output should be ignored and simply listed as unspent - which is correct. The wallet software can handle the coin selection criteria.

Would Sparrow handle this correctly?

Indeed it did not. I've now implemented this in sparrowwallet/drongo@57290a2 and 237f978.

[kdmukai]

Bump! Behavior seems to be the same in Sparrow v1.8.1. Neither mature nor immature coinbase outputs are found.

Same setup: bitcoind (v24.0.1) in regtest.

Is there a workaround?

[craigraw]

On the list to add to Cormorant (Sparrow's Bitcoin Core RPC library) for the next version. The workaround for now is to use an Electrum server.