This reverts commit 49f9584613.
Now that we are depending unconditionally on the Rust Equihash
validator, CheckEquihashSolution() can revert to being a non-contextual
check.
This also fixes a segfault that would occur during reindexing if the
consensus rules were altered such that a previously-valid block would
become invalid, and the node's block files contained blocks in a
specific order. It was encountered while testing the Canopy NU on
testnet (due to a bug in the implementation of ZIP 212 that was
separately fixed in zcash/zcash#4604).
This requires moving CheckEquihashSolution() to
ContextualCheckBlockHeader() for all but the genesis block, which has no
effect on consensus; it just means that an invalid Equihash solution is
rejected slightly later in the block validation process.
When the difficulty adjustment algorithm was altered, the special testnet
min-difficulty case was maintained, but the difficulty adjustment for the
following block then adjusted from min-difficulty instead of from the last
non-min-difficulty block. This caused the difficulty on the testnet to sawtooth
instead of stabilising. The intended behaviour is restored here.
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.
Split GetNextWorkRequired() into two functions to allow the difficulty calculations to
be tested without requiring a full blockchain.
Add unit tests to cover basic difficulty calculation, plus each of the min/max actual
time, and maximum difficulty target conditions.
- ensures a consistent usage in header files
- also add a blank line after the copyright header where missing
- also remove orphan new-lines at the end of some files
Jack Grigg
Homu
Eirik Ogilvie-Wigley
Daira Hopwood
Simon
Pieter Wuille
Jorge Timón
Ross Nicoll
Wladimir J. van der Laan
sandakersmann
Michael Ford
jtimon
Philip Kaufmann
jtimon