`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.
ListTransactions(*locked_chain, pwallet, tx, 0, true, transactions, filter);
        }
    }
    
    
    UniValue removed(UniValue::VARR);
    while (include_removed && paltindex && paltindex != pindex) {
        CBlock block;
        if (!ReadBlockFromDisk(block, paltindex, Params().GetConsensus())) {
            throw JSONRPCError(RPC_INTERNAL_ERROR, "Can't read block from disk");
        }
        for (const CTransactionRef& tx : block.vtx) {
            auto it = pwallet->mapWallet.find(tx->GetHash());
            if (it != pwallet->mapWallet.end()) {
                
                
                ListTransactions(*locked_chain, pwallet, it->second, -100000000, true, removed, filter);
            }
        }
        paltindex = paltindex->pprev;
    }
    CBlockIndex *pblockLast = chainActive[chainActive.Height() + 1 - target_confirms];
    uint256 lastblock = pblockLast ? pblockLast->GetBlockHash() : uint256();
    UniValue ret(UniValue::VOBJ);
    ret.pushKV("transactions", transactions);
    if (include_removed) ret.pushKV("removed", removed);
    ret.pushKV("lastblock", lastblock.GetHex());
    return ret;
}
static UniValue gettransaction(const JSONRPCRequest& request)