wallet: upgrading a non-persistent coin lock to persistent leaves a stale lock on the spent output after restart #36304

Is there an existing issue for this?

• I have searched the existing issues

Current behaviour

I did the following against a wallet:

1. fundrawtransaction with "lockUnspents": true
2. lockunspent false [those inputs] persistent=true to make the same locks survive a restart.
3. Signed and broadcast the funded transaction, then mined a block.

After step 3 listlockunspent is empty, since the wallet released the locks when it saw the inputs get spent. But after restarting bitcoind and loading the wallet, listlockunspent lists those inputs again, even though they are spent and gettxout returns nothing for them.

Expected behaviour

A lock that the wallet already released when the output was spent should not come back after a restart.

Steps to reproduce

an LLM wrote this script but it follows the steps I did against the wallet that surfaced the issue

bitcoin-cli -regtest createwallet w
ADDR=$(bitcoin-cli -regtest -rpcwallet=w getnewaddress)
bitcoin-cli -regtest -rpcwallet=w generatetoaddress 101 $ADDR

# 1. fund a transaction with lockUnspents
RAW=$(bitcoin-cli -regtest -rpcwallet=w createrawtransaction '[]' "{\"$(bitcoin-cli -regtest -rpcwallet=w getnewaddress)\":1}")
FUNDED=$(bitcoin-cli -regtest -rpcwallet=w fundrawtransaction $RAW '{"lockUnspents":true,"minconf":1}' | jq -r .hex)
LOCKED=$(bitcoin-cli -regtest -rpcwallet=w listlockunspent | jq -c .)
echo $LOCKED                      # one outpoint

# 2. re-lock that outpoint with persistent=true
bitcoin-cli -regtest -rpcwallet=w lockunspent false "$LOCKED" true

# 3. spend the locked output and confirm it
SIGNED=$(bitcoin-cli -regtest -rpcwallet=w signrawtransactionwithwallet $FUNDED | jq -r .hex)
bitcoin-cli -regtest sendrawtransaction $SIGNED
bitcoin-cli -regtest -rpcwallet=w listlockunspent      # [] as expected
bitcoin-cli -regtest -rpcwallet=w generatetoaddress 1 $ADDR

# 4. reload the wallet (a bitcoind restart behaves the same)
bitcoin-cli -regtest unloadwallet w
bitcoin-cli -regtest loadwallet w
bitcoin-cli -regtest -rpcwallet=w listlockunspent      # the spent outpoint is back
bitcoin-cli -regtest gettxout <txid> <vout>            # empty

Relevant log output

No response

How did you obtain Bitcoin Core

Compiled from source

What version of Bitcoin Core are you using?

v30.2

Operating system and version

Ubuntu 24.04 LTS

Machine specifications

No response