2283b9cd1e test: add tests for LoadBlockIndex when using multiple chainstates (James O'Beirne)
0fd599a51a validation: have LoadBlockIndex account for snapshot use (James O'Beirne)
d0c6e61f5d validation: don't modify genesis during snapshot load (James O'Beirne)
Pull request description:
This is part of the [assumeutxo project](https://github.com/bitcoin/bitcoin/projects/11) (parent PR: #15606)
---
Currently, `BlockManager::LoadBlockIndex` adds all blocks that have downloaded transactions to the active chain state's `setBlockIndexCandidates` set, ignoring the background chain state.
This PR changes ChainstateManager::LoadBlockIndex to update `setBlockIndexCandidates` in the background chain, not just the active chain. In the active chain, the same blocks are added as before. In the background chain, only blocks that have actually been validated, not blocks marked assumed-valid are added so the background chain will continue to download and validate assumed-valid blocks.
ACKs for top commit:
MarcoFalke:
Concept ACK 2283b9cd1e🤽
Sjors:
utACK 2283b9cd1e
Tree-SHA512: 7c9a80802df4722d85d12b78d2e7f628ac5f11cb8be66913d5c3230339bd1220c6723805509d4460826a17d1dc04b0ae172eb7d09ac0ea5dc5e41d77975cbd5e
Avoid modifying the genesis block index entry during snapshot load. This
is because, in a future change that fixes LoadBlockIndex for UTXO
snapshots, we detect block index entries that are reliant on
assumed-valid ancestors and treat them specially.
Since the genesis block doesn't have BLOCK_VALID_SCRIPTS, it would be
erroneously marked BLOCK_ASSUMED_VALID during snapshot load if we didn't
skip it here. This would cause a "setBlockIndexCandidates() empty"
assertion to be tripped since all block index entries would be marked
assume-valid due to genesis, which is never re-validated.
There's probably no good reason to modify the genesis block index entry
during snapshot load anyway...
After feedback from Russ, I realized that there are some extraneous assumeutxo methods
that are not necessary and probably just overly confusing. These include
- `Validated*()`
- `IsBackgroundIBD()`
and they can be removed.
Since we now have multiple chainstate objects, only one of them is active at any given
time. An active chainstate has a mempool, but there's no point to others having one.
This change will simplify proposed assumeutxo semantics. See the discussion here:
https://github.com/bitcoin/bitcoin/pull/15606#pullrequestreview-692965905
Co-authored-by: Russell Yanofsky <russ@yanofsky.org>
This value is no longer used and is instead specified statically
in chainparams. This change means that previously generated
snapshots will no longer be usable.
This fixes an oversight from the move of nChainTx from the user-supplied
snapshot metadata into the hardcoded assumeutxo chainparams.
Since the nChainTx is now unused in the metadata, it should be removed
in a future commit.
Seems odd to have an option for non-deterministic tests
when the goal should be for all tests to be deterministic.
Can be reviewed with `--ignore-all-space`.
3eb94ec81b sync: Use decltype(auto) return type for WITH_LOCK (Carl Dong)
Pull request description:
> Now that we're using C++17, we can use the decltype(auto) return type
> for functions and lambda expressions.
>
> As demonstrated in this commit, this can simplify cases where previously
> the compiler failed to deduce the correct return type.
>
> Just for reference, for the "assign to ref" cases fixed here, there are
> 3 possible solutions:
>
> - Return a pointer and immediately deref as used before this commit
> - Make sure the function/lambda returns declspec(auto) as used after
> this commit
> - Class& i = WITH_LOCK(..., return std::ref(...));
>
> -----
>
> References:
> 1. https://en.cppreference.com/w/cpp/language/function#Return_type_deduction
> 2. https://en.cppreference.com/w/cpp/language/template_argument_deduction#Other_contexts
> 3. https://en.cppreference.com/w/cpp/language/auto
> 4. https://en.cppreference.com/w/cpp/language/decltype
>
> Explanations:
> 1. https://stackoverflow.com/a/21369192
> 2. https://stackoverflow.com/a/21369170
Thanks to sipa and ryanofsky for helping me understand this
ACKs for top commit:
jnewbery:
utACK 3eb94ec81b
hebasto:
ACK 3eb94ec81b, I have reviewed the code and it looks OK, I agree it can be merged. I have verified possible warnings:
ryanofsky:
Code review ACK 3eb94ec81b
Tree-SHA512: 5f55c7722aeca8ea70e5c1a8db93e93ba0e356e8967e7f607ada38003df4b153d73c29bd2cea8d7ec1344720d37d857ea7dbfd2a88da1d92e0e9cbb9abd287df
Previously, the validation_chainstatemanager_tests test suite
instantiated its own duplicate ChainstateManager on which tests were
performed.
This wasn't a problem for the specific actions performed in
that suite. However, the existence of this duplicate ChainstateManager
and the fact that many of our validation static functions reach for
g_chainman, ::Chain(state|)Active means we may end up acting on two
different CChainStates should we write more extensive tests in the
future.
This change adds a new ChainTestingSetup which performs all
initialization previously done by TestingSetup except:
1. RPC command registration
2. ChainState initialization
3. Genesis Activation
4. {Ban,Conn,Peer}Man initialization
Means that we will no longer need to initialize a duplicate
ChainstateManger in order to test the initialization codepaths of
CChainState and ChainstateManager.
Lastly, this change has the additional benefit of allowing for
review-only assertions meant to show correctness to work in future work
de-globalizing g_chainman.
In the test chainstatemanager_rebalance_caches, an additional
LoadGenesisBlock call is added as MaybeReblanaceCaches eventually calls
FlushBlockFile, which tries to access vinfoBlockFile[nLastBlockFile],
which is out of bounds when LoadGenesisBlock hasn't been called yet.
-----
Note for the future:
The class con/destructor inheritance structure we have for these
TestingSetup classes is probably not the most suitable abstraction. In
particular, for both TestingSetup and ChainTestingSetup, we need to stop
the scheduler first before anything else. Otherwise classes depending on
the scheduler may be referenced by the scheduler after said classes are
freed. This means that there's no clear parallel between our teardown
code and C++'s destructuring order for class hierarchies.
Future work should strive to coalesce (as much as possible) test and
non-test init codepaths and perhaps structure it in a more fail-proof
way.
Also adds CCoinsViewCache::ReallocateCache() to attempt to free
memory that the cacheCoins's allocator may be hanging onto when
downsizing the cache.
Adds `CChainState::m_coins{tip,db}_cache_size_bytes` data members
so that we can reference cache size on a per-chainstate basis for
flushing.
