`ScanForWalletTransactions()` has the following comment about its return value:

```
 * Returns null if scan was successful. Otherwise, if a complete rescan was not
 * possible (due to pruning or corruption), returns pointer to the most recent
 * block that could not be scanned.
```

This is not strictly true. If `abortrescan` is called, then `ScanForWalletTransactions()` will return `nullptr`, even though the scan wasn't successful to the tip.

This in turn causes a minor bug in `importmulti`, where the call doesn't return the correct error and warning about potentially not finding transactions if `abortrescan` was called.

I think the correct fix is for `ScanForWalletTransactions()` to inform the caller that the rescan was aborted.
{
    {
        LOCK(cs_wallet); 
        
        std::string strAddress = EncodeDestination(address);
        for (const std::pair<const std::string, std::string> &item : mapAddressBook[address].destdata)
        {
            WalletBatch(*database).EraseDestData(strAddress, item.first);
        }
        mapAddressBook.erase(address);
    }
    NotifyAddressBookChanged(this, address, "", ::IsMine(*this, address) != ISMINE_NO, "", CT_DELETED);
    WalletBatch(*database).ErasePurpose(EncodeDestination(address));
    return WalletBatch(*database).EraseName(EncodeDestination(address));
}
const std::string& CWallet::GetLabelName(const CScript& scriptPubKey) const