Quote from: MPOE-PR on March 12, 2013, 05:21:19 AM

Quote from: coqui33 on March 12, 2013, 05:06:02 AM

MPOE-PR: You seem to be under the mistaken impression that the hard fork was caused by something in 0.8. Not so. The block that 0.7 choked on was a valid block. The bug was lurking in 0.7 all along, and was merely uncovered by a 0.8 miner's block. You might as well blame the physician who taps your kneecap to check reflexes, for the bone cancer that he unexpectedly discovers there.

I am not under any suck mistaken impression. Please read what's actually being said, it will help.

The presence of a 250k arbitrary block limit prevented the underlying problem of the db from being discovered until that moment when a perfect storm composed out of a db upgrade and the limit removal created two almost equal miner bases. This could have easily been avoided by simply not relying on magic numbers. It will ever be the case that whenever code contains arbitrary numbers based on arbitrary assumptions that code will break spectacularly.

That is not correct. v0.7 nodes accepted a 1MB block on testnet. The issue was more complex then just the size of the block. By the protocol the block which was rejected by some nodes SHOULD have been accepted. The 250kb soft limit was simply a default for block construction. Even with it in place nodes should have accepted properly constructed blocks up to the 1MB limit. It also appears not all v0.7 nodes were affected. Some accepted the problem block and some didn't. The defect/limit in BDB wasn't documented and didn't occur in all versions/platforms. It appears the number of transactions being changed as a result of the block validation crossed some "magic code" not in the Bitcoin source code but undocumented in some implementations of BDB.

v0.7 reliance on BDB caused it to be fundamentally broken/flawed. Its actions weren't consistent with the documented protocol, the higher level source code, or anyone's understanding/expectation of what should have happened. Nobody was saying/thinking oh yeah if you make a block with more than x transaction it will abort, cause a rollback, and result in a rejection. It was a landmine.