I'm not sure, bu I think there is one small bug, that might cause perfectly fine generated block to be rejected.
In one of the anonymous objects, there's following piece (which happens to be my favourite piece of code in nxt btw):
int elapsedTime = [b]getEpochTime(System.currentTimeMillis())[/b] - lastBlock.timestamp;
if (elapsedTime > 0) {
BigInteger target = BigInteger.valueOf(Block.getBaseTarget()).multiply(BigInteger.valueOf(account.getEffectiveBalance())).multiply(BigInteger.valueOf(elapsedTime));
if (hits.get(account).compareTo(target) < 0) { // [b]FIRST[/b] check
account.[u]generateBlock[/u](user.secretPhrase);
}
}
Now inside
generateBlock, there's following piece:
Block block = new Block(1, [b]getEpochTime(System.currentTimeMillis())[/b], lastBlock, newTransactions.size(), 0, 0, 0, null, Crypto.getPublicKey(secretPhrase), null, new byte[64]);
block.transactions = new long[block.numberOfTransactions];
int i = 0;
⋮
// fill in missing stuff in the block
⋮
block.blockSignature = Crypto.sign(data2, secretPhrase);
JSONObject request = block.getJSONObject(newTransactions);
request.put("requestType", "processBlock");
if (block.verifyBlockSignature() && block.[u]verifyGenerationSignature[/u]()) {
And in
verifyGenerationSignature there is following check (in both blocks):
int elapsedTime = timestamp - previousBlock.timestamp;
BigInteger target = BigInteger.valueOf(Block.getBaseTarget()).multiply(BigInteger.valueOf(account.getEffectiveBalance())).multiply(BigInteger.valueOf(elapsedTime));
byte[] generationSignatureHash = MessageDigest.getInstance("SHA-256").digest(generationSignature);
BigInteger hit = new BigInteger(1, new byte[] {generationSignatureHash[7], generationSignatureHash[6], generationSignatureHash[5], generationSignatureHash[4], generationSignatureHash[3], generationSignatureHash[2], generationSignatureHash[1], generationSignatureHash[0]});
if (hit.compareTo(target) >= 0) { // [b]SECOND[/b] check
return false;
}
Now, notice, that in FIRST check, value of
target will most likely be different, than in SECOND check
(because in FIRST check value of
elapsedTime will probably be different than value of
elapsedTime in second check... most times,
the difference will probably small enough, and SECOND check might pass, but not always...)
Wouldn't it be better, to pass value returned by call to
getEpochTime(System.currentTimeMillis()), to generateBlock() ?
No, we already checked that the hit didn't miss the target.
