Removes dependency on unsafe and deprecated uint256S.
This makes parsing more strict, by returning an error
when the input contains more than 64 hex digits.
FromUserHex will be used in future commits to construct
uint256 instances from user hex input without being
unnecessarily restrictive on formatting by allowing
0x-prefixed input that is shorter than 64 characters.
59ff17e5af miner: adjust clock to timewarp rule (Sjors Provoost)
e929054e12 Add timewarp attack mitigation test (Sjors Provoost)
e85f386c4b consensus: enable BIP94 on regtest (Sjors Provoost)
dd154b0568 consensus: lower regtest nPowTargetTimespan to 144 (Sjors Provoost)
Pull request description:
Because #30647 reduced the timewarp attack threshold from 7200s to 600s, our miner code will fail to propose a block template (on testnet4) if the last block of the previous period has a timestamp two hours in the future. This PR fixes that and also adds a test.
The non-test changes in the last commit should be in v28, otherwise miners have to patch it themselves. If necessary I can split that out into a separate PR, but I prefer to get the tests in as well.
In order to add the test, we activate BIP94 on regtest.
In order for the test to run faster, we reduce its difficulty retarget period to 144, the same number that's already used for softfork activation logic. Regtest does not actually adjust its difficulty, so this change has no effect (except for `getnetworkhashps`, see commit).
An alternative approach would be to run this test on testnet4, by hardcoding its first 2015 in the test suite. But since the timewarp mitigation is a serious candidate for a future mainnet softfork, it seems better to just deploy it on regtest.
The next commits add a test and fix the miner code.
The `MAX_TIMEWARP` constant is moved to `consensus.h` so both validation and miner code have access to it.
ACKs for top commit:
achow101:
ACK 59ff17e5af
fjahr:
ACK 59ff17e5af
glozow:
ACK 59ff17e5af
Tree-SHA512: 50af9fdcba9b0d5c57e1efd5feffd870bd11b5318f1f8b0aabf684657f2d33ab108d5f00b1475fe0d38e8e0badc97249ef8dda20c7f47fcc1698bc1008798830
Integer promotion will already turn the `signed` into `unsigned` in
those lines. However, make the `unsigned` explicit so that the code is
clearer and a compiler warning is avoided when switching to m_rng:
| test/validation_block_tests.cpp: warning: comparison of integers of different signs: 'int' and 'const unsigned int' [-Wsign-compare]
| 136 | bool gen_invalid = m_rng.randrange(100) < invalid_rate;
| | ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~
| 137 | bool gen_fork = m_rng.randrange(100) < branch_rate;
| | ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~
| 2 warnings generated.
rand_cache is unused since commit
16329224e7, so it can be removed
rand_seed is wrong since commit
022cf47dd7, because it is no longer
printing the seed that was used to seed the global random context in
tests. Instead, it prints a (random-ish) value derived from the global
random context via InsecureRand256().
Finally, the for loop creating new prevector_tester objects will always
use the same seed since commit fae43a97ca,
because repeated calls to SeedInsecureRand/SeedRandomForTest will always
reseed the global with the same "static const" seed.
Fix all issues by
* removing the unused rand_cache,
* removing the call to SeedRandomForTest which restored the same seed on
every call in the process, and
* Reseeding the global random context with the (random-ish) rand_seed.
fa899fb7aa fuzz: Speed up utxo_snapshot fuzz target (MarcoFalke)
fa386642b4 fuzz: Speed up utxo_snapshot by lazy re-init (MarcoFalke)
fa645c7a86 fuzz: Remove unused DataStream object (MarcoFalke)
fae8c73d9e test: Disallow fee_estimator construction in ChainTestingSetup (MarcoFalke)
Pull request description:
Two commits to speed up unit and fuzz tests.
Can be tested by running the fuzz target and looking at the time it took, or by looking at the flamegraph. For example:
```
FUZZ=utxo_snapshot perf record -g --call-graph dwarf ./src/test/fuzz/fuzz -runs=100
hotspot ./perf.data
ACKs for top commit:
TheCharlatan:
Re-ACK fa899fb7aa
marcofleon:
Re ACK fa899fb7aa
brunoerg:
ACK fa899fb7aa
Tree-SHA512: d3a771bb12d7ef491eee61ca47325dd1cea5c20b6ad42554babf13ec98d03bef8e7786159d077e59cc7ab8112495037b0f6e55edae65b871c7cf1708687cf717
The flags SECP256K1_CONTEXT_{SIGN,VERIFY} have been deprecated since
libsecp256k1 version 0.2 (released in December 2022), with the
recommendation to use SECP256K1_CONTEXT_NONE instead.
This currently has no effect due to fPowNoRetargeting,
except for the getnetworkhashps when called with -1.
It will when the next commit enforces the timewarp attack mitigation on regtest.
16e95bda86 Move maximum timewarp attack threshold back to 600s from 7200s (Matt Corallo)
Pull request description:
In 6bfa26048d the testnet4 timewarp attack fix block time variation was increased from the Great Consensus Cleanup value of 600s to 7200s on the thesis that this allows miners to always create blocks with the current time. Sadly, doing so does allow for some nonzero inflation, even if not a huge amount.
While it could be that some hardware ignores the timestamp provided to it over Stratum and forces the block header timestamp to the current time, I'm not aware of any such hardware, and it would also likely suffer from random invalid blocks due to relying on NTP anyway, making its existence highly unlikely.
This leaves the only concern being pools, but most of those rely on work generated by Bitcoin Core (in one way or another, though when spy mining possibly not), and it seems likely that they will also not suffer any lost work. While its possible that a pool does generate invalid work due to spy mining or otherwise custom logic, it seems unlikely that a substantial portion of hashrate would do so, making the difference somewhat academic (any pool that screws this up will only do so once and the network would come out just fine).
Further, while we may end up deciding these assumptions were invalid and we should instead use 7200s, it seems prudent to try with the value we "want" on testnet4, giving us the ability to learn if the compatibility concerns are an issue before we go to mainnet.
ACKs for top commit:
fjahr:
tACK 16e95bda86
achow101:
ACK 16e95bda86
murchandamus:
crACK 16e95bda86
Tree-SHA512: ae46d03b728b6e23cb6ace64c9813bc01c01e38dd7f159cf0fab53b331ef84b3b811edab225453ccdfedb53b242f55b0efd69829782657490fe393d24dacbeb2
