importprivkey found bitcoins even with rescan set to false #10666

I imported a private key to a funded address with importprivkey {privateKey} "" false expecting that the wallet would only know about future transactions to this address. However it immediately found the funds (which had 4 confirmations), despite rescan set to false. My expectation was that it would only find funds for future transactions. Looking at the source code I can't see how this would happen and how many blocks it actually does scan back.

I'm not sure if the current behavior is intended or not, but it could be made a lot more clear

Did it do a rescan? (hard to miss, your node would hang for some time and it prints to debug.log)

Yeah, there was no rescan. I am able to reproduce by:

Create an address on bitaddress.org Send some bitcoin to that address Wait until the bitcoin have got a couple of confirmations Check the balance Import private key with false set for rescan Check the balance, and see that it found the money

I'm also totally sure I didn't run with rescan, because if I try:

Rescan is disabled in pruned mode (code -4)

we were able to see the coins associated with the imported privkeys instantly.

What made you think that would happen? The wallet only knows about your coins if it rescans the blockchain. If you don't have it rescan, then it won't know about any of your coins.

The call returned w/o an error but the coins did not show up

As is expected.

repeating the same importprivkey with rescan=true had no effect.

What exactly is the command you are running?

random though: do you import an HD derived private key that uses the same seed and derivation-path than core does (maybe exported your xpriv via dumpwallet)?

Or: do you have "rescan=1" in your bitcoin.conf?

random though: do you import an HD derived private key that uses the same seed and derivation-path than core does (maybe exported your xpriv via dumpwallet)?

No. The issue is easily reproducible with arbitrary addresses

Or: do you have "rescan=1" in your bitcoin.conf?

Nope

Transforming your description into a python test, I could not reproduce on current master:

        # clean chain. set up nodes[1] with "-prune=550". Mine 101 blocks on nodes[0]

        address_new = self.nodes[0].getnewaddress()
        self.nodes[0].sendtoaddress(address_new, 0.1)
        self.nodes[0].generate(4)
        self.nodes[1].importprivkey(privkey=self.nodes[0].dumpprivkey(address_new), rescan=False)
        assert self.nodes[1].getbalance() == 0

Did you send the coins to the new address from the wallet you are importing into? If so I'd imagine the transaction would already be 'yours' as a sent transaction in the wallet, might be the cause.

Edit: indeed, a test along these lines reproduces the behaviour:

# clean chain. set up nodes[1] with "-prune=550"

address_new = self.nodes[0].getnewaddress()
self.nodes[1].generate(101)
self.nodes[1].sendtoaddress(address_new, 49)
self.nodes[1].generate(1)
balance_before = self.nodes[1].getbalance()
self.nodes[1].importprivkey(privkey=self.nodes[0].dumpprivkey(address_new), rescan=False)
assert self.nodes[1].getbalance() == balance_before

Test fails with nearly all 100 mature BTC left, just minus the fee for the transaction. Issue probably should be closed then