65aaf9495d refactor: move `update_*` structs from txmempool.h to .cpp file (Sebastian Falbesoner)
9947ce6262 refactor: use const reference for parents in `CTxMemPool::UpdateAncestorsOf` (Sebastian Falbesoner)
Pull request description:
These helpers are exclusively used in txmempool.cpp, hence they should also be moved there. The PR also contains a commit which fixes const-correctness for parents in `CTxMemPool::UpdateAncestorsOf` and declares them as reference to avoid a copy.
ACKs for top commit:
promag:
Code review ACK 65aaf9495d. Verified move-only commit locally.
Tree-SHA512: 7ce29f3ba0e68b5355001f27725b00f6d54cc993015356eb40b61b8cdd17db49b980f4c3d798c8e0c940d245dc3a72c474bb9ff3c0ee971ead450786076812c2
082c5bf099 [refactor] pass coinsview and height to check() (glozow)
ed6115f1ea [mempool] simplify some check() logic (glozow)
9e8d7ad5d9 [validation/mempool] use Spend/AddCoin instead of UpdateCoins (glozow)
09d18916af MOVEONLY: remove single-use helper func CheckInputsAndUpdateCoins (glozow)
e8639ec26a [mempool] remove now-unnecessary code (glozow)
54c6f3c1da [mempool] speed up check() by using coins cache and iterating in topo order (glozow)
30e240f65e [bench] Benchmark CTxMemPool::check() (glozow)
cb1407196f [refactor/bench] make mempool_stress bench reusable and parameterizable (glozow)
Pull request description:
Remove the txmempool <-> validation circular dependency by removing txmempool's dependency on validation. There are two functions in txmempool that need validation right now: `check()` and `removeForReorg()`. This PR removes the dependencies in `check()`.
This PR also improves the performance of `CTxMemPool::check()` by walking through the entries exactly once, in ascending ancestorcount order, which guarantees that we see parents before children.
ACKs for top commit:
jnewbery:
reACK 082c5bf099
GeneFerneau:
tACK [082c5bf](https://github.com/bitcoin/bitcoin/pull/23157/commits/082c5bf099c64e3d27abe9b68a71ce500b693e7e)
rajarshimaitra:
tACK https://github.com/bitcoin/bitcoin/pull/23157/commits/082c5bf099c64e3d27abe9b68a71ce500b693e7e
theStack:
Code-review ACK 082c5bf099
Tree-SHA512: 40ac622af1627b5c3e6abb4f0f035d833265a8c5e8dc88faf5354875dfb5137f137825e54bbd2a2668ed37b145c5d02285f776402629f58596e51853a9a79d29
No transaction in the mempool should ever be a coinbase.
Since mempoolDuplicate's backend is the chainstate coins view, it should
always contain the coins available.
UpdateCoins is an unnecessary dependency on validation. All we need to
do is add and remove coins to check inputs. We don't need the extra
logic for checking coinbases and handling TxUndos.
Also remove the wrapper function in validation.h which constructs a
throwaway TxUndo object before calling UpdateCoins because it is now
unused.
Remove variables used for keeping track of mempool transactions for
which we haven't processed the parents yet. Since we're iterating in
topological order now, they're always unused.
No behavior changes.
Before, we're always adding transactions to the "check later" queue if
they have any parents in the mempool. But there's no reason to do this
if all of its inputs are already available from mempoolDuplicate.
Instead, check for inputs, and only mark fDependsWait=true if the
parents haven't been processed yet.
Reduce the amount of "check later" transactions by looking at
ancestors before descendants. Do this by iterating through them in
ascending order by ancestor count. This works because a child will
always have more in-mempool ancestors than its parent.
We should never have any entries in the "check later" queue
after this commit.
This removes a bunch of boilerplate, makes the code easier to read.
Also, C++11 member initialization avoids accidental uninitialized
members.
Can be reviewed with the git option "--word-diff-regex=." or with "git
difftool --tool=meld".
When calculating ancestor/descendant counts for transactions in the
package, as a heuristic, count every transaction in the package as an
ancestor and descendant of every other transaction in the package.
This may overestimate, but will not underestimate, the
ancestor/descendant counts. This shortcut still produces an accurate
count for packages of 1 parent + 1 child.
This does not change existing behavior.
The ancestor/descendant limits are inclusive of the entries themselves,
but CalculateAncestorsAndCheckLimits() does not need access to them.
Allow CheckSequenceLocks to use heights and coins from any CoinsView and
CBlockIndex provided. This means that CheckSequenceLocks() doesn't need
to hold the mempool lock or cs_main. The caller is responsible for
ensuring the CoinsView and CBlockIndex are consistent before passing
them in. The typical usage is still to create a CCoinsViewMemPool from
the mempool and grab the CBlockIndex from the chainstate tip.
In #21415 we decided to return `std::optional` rather than `{}` for
uninitialized values. This PR repalces the two remaining usages of `{}`
with `std::nullopt`.
As a side-effect, this also quells the spurious GCC 10.2.x warning that
we've had reported quite a few times. i.e #21318, #21248, #20797.
```bash
txmempool.cpp: In member function ‘CTxMemPool::setEntries CTxMemPool::GetIterSet(const std::set<uint256>&) const’:
txmempool.cpp:898:13: warning: ‘<anonymous>’ may be used uninitialized in this function [-Wmaybe-uninitialized]
898 | return {};
| ^
```
