`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.
masterKey.SetSeed(seed.begin(), seed.size());
    
    
    masterKey.Derive(accountKey, BIP32_HARDENED_KEY_LIMIT);
    
    assert(internal ? CanSupportFeature(FEATURE_HD_SPLIT) : true);
    accountKey.Derive(chainChildKey, BIP32_HARDENED_KEY_LIMIT+(internal ? 1 : 0));
    
    do {
        
        
        
        if (internal) {
            chainChildKey.Derive(childKey, hdChain.nInternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            metadata.hdKeypath = "m/0'/1'/" + std::to_string(hdChain.nInternalChainCounter) + "'";
            hdChain.nInternalChainCounter++;
        }
        else {
            chainChildKey.Derive(childKey, hdChain.nExternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            metadata.hdKeypath = "m/0'/0'/" + std::to_string(hdChain.nExternalChainCounter) + "'";
            hdChain.nExternalChainCounter++;
        }
    } while (HaveKey(childKey.key.GetPubKey().GetID()));
    secret = childKey.key;
    metadata.hd_seed_id = hdChain.seed_id;
    
    if (!batch.WriteHDChain(hdChain))
        throw std::runtime_error(std::string(__func__) + ": Writing HD chain model failed");
}
bool CWallet::AddKeyPubKeyWithDB(WalletBatch &batch, const CKey& secret, const CPubKey &pubkey)