Changing the order of difficulty calculation operations to divide first doesn't
affect the result significantly, but ensures we never overflow the arith_uint256
during multiplication and get an artificial jump in difficulty.
Changes to bloom tests were done by running the following commands:
sed -i 's/\(CDataStream stream(ParseHex(".\{152\}\)\(.\{8\}\)/\100000000000000000000000000000000000000000000000000000000\200/' src/test/bloom_tests.cpp
sed -i 's/\(vector<unsigned char> vch = ParseHex(".\{152\}\)\(.\{8\}\)/\100000000000000000000000000000000000000000000000000000000\200/' src/test/bloom_tests.cpp
and then reverting the single change to the transaction line.
The main and test networks are configured to use parameters that are currently
low-memory but usable with the basic solver; they will be increased once the
solver is optimised. The regtest network is configured to have extremely low
memory usage for speed.
Note that Bitcoin's double-hasher is used for the difficulty check. This does
not match the paper, but is simpler than changing the block header
serialization. Single hashing is kept for the EquiHash solver because there is
no requirement on execution time there, only on memory usage.
Some specifics on consensus changes:
* Transactions must be anchored to a real anchor in the chain.
* Anchors are pushed and popped during ConnectBlock/DisconnectBlock as appropriate.
* DisconnectTip triggers evictions, under some circumstances, of transactions in the
mempool which are anchored to roots that are no longer valid.
* Commitments append to the tree at the current best root during ConnectBlock.
* PourTxs cannot appear in coinbase transactions.
* Transactions can only contain empty vin/vouts if they contain a PourTx.
* PourTx public values must be well-formed (not negative or too large).
* Transactions cannot have the same serial twice throughout all PourTxs.
Transactions of version 2 and above contain a `vpour` field which is a vector of `CPourTx`
objects that embody our protocol. We introduce serialization primitives for boost::array
(we intend for changing the amount of inputs and outputs in the circuit to be simple).
SIGHASH_* operations hash this field like any other for now.
Previously, the undo weren't being flushed during a reindex because
fKnown was set to true in FindBlockPos. That is the correct behaviour
for block files as they aren't being touched, but undo files are
touched.
This changes the behaviour to always flush when switching to a new file
(even for block files, though that isn't really necessary).
Rebased-From: 22e780737db57bcb18b3824eb8158e19a4775cb6
Github-Pull: #6948
