Rather than individually calling addUnchecked for each transaction added in a
changeset (after removing all the to-be-removed transactions), instead we can
take advantage of boost::multi_index's splicing features to extract and insert
entries directly from the staging multi_index into mapTx.
This has the immediate advantage of saving allocation overhead for mempool
entries which have already been allocated once. This also means that the memory
locations of mempool entries will not change when transactions go from staging
to the main mempool.
Additionally, eliminate addUnchecked and require all new transactions to enter
the mempool via a CTxMemPoolChangeSet.
refactor: CBlockHeaderAndShortTxIDs constructor now always takes an explicit nonce.
test: Make blockencodings_tests deterministic using fixed seed providing deterministic
CBlockHeaderAndShortTxID nonces and dummy transaction IDs.
Fixes very rare flaky test failures, where the ShortIDs of test transactions collide, leading to
`READ_STATUS_FAILED` from PartiallyDownloadedBlock::InitData and/or `IsTxAvailable` giving `false`
when the transaction should actually be available.
* Use a new `FastRandomContext` with a fixed seed in each test, to ensure 'random' uint256s
used as fake prevouts are deterministic, so in-turn test txids and short IDs are deterministic
and don't collide causing very rare but flaky test failures.
* Add new test-only/internal initializer for `CBlockHeaderAndShortTxIDs` that takes a specified
nonce to further ensure determinism and avoid rare but undesireable short ID collisions.
In a test context this nonce is set to a fixed known-good value. Normally it is random, as
previously.
Flaky test failures can be reproduced with:
```patch
diff --git a/src/blockencodings.cpp b/src/blockencodings.cpp
index 695e8d806a..64d635a97a 100644
--- a/src/blockencodings.cpp
+++ b/src/blockencodings.cpp
@@ -44,7 +44,8 @@ void CBlockHeaderAndShortTxIDs::FillShortTxIDSelector() const {
uint64_t CBlockHeaderAndShortTxIDs::GetShortID(const Wtxid& wtxid) const {
static_assert(SHORTTXIDS_LENGTH == 6, "shorttxids calculation assumes 6-byte shorttxids");
- return SipHashUint256(shorttxidk0, shorttxidk1, wtxid) & 0xffffffffffffL;
+ // return SipHashUint256(shorttxidk0, shorttxidk1, wtxid) & 0xffffffffffffL;
+ return SipHashUint256(shorttxidk0, shorttxidk1, wtxid) & 0x0f;
}
```
to increase the likelihood of a short ID collision; and running
```shell
set -e;
n=0;
while (( n++ < 5000 )); do
src/test/test_bitcoin --run_test=blockencodings_tests;
done
```
This new test uses the `vExtraTxnForCompact` (`extra_txn`) vector of
optional orphan/conflicted/etc. transactions to provide a transaction
in a compact block that was not otherwise present in our mempool.
This also covers an improbable nullptr deref bug addressed in
bf031a517c (#29752) where the
`extra_txn` vec/circular-buffer was sometimes null-initialized and
not yet filled when dereferenced in `PartiallyDownloadedBlock::InitData`.
All `CTransactionRef` have `.GetWitnessHash()` that returns a cached `const Wtxid` (since fac1223a56),
so we don't need to pass transaction refs around with their IDs as they're easy to get from a ref.
After this commit, there should be no explicit instantiation of
CTxMemPool in src/test other than those in fuzz/ and setup_common
-BEGIN VERIFY SCRIPT-
find_regex="CTxMemPool\s+([^;({]+)(|\(\)|\{\});" \
&& git grep -l -E "$find_regex" -- src/test \
| grep -v -e "^src/test/util/setup_common.cpp$" \
-e "^src/test/fuzz/" \
| xargs sed -i -E "s@$find_regex@CTxMemPool\& \1 = *Assert(m_node.mempool);@g"
-END VERIFY SCRIPT-
All uses of CBlockHeaderAndShortTxIDs in the product code are
constructed with fUseWTXID=true, so remove the parameter.
There is one use of the CBlockHeaderAndShortTxIDs constructor with
fUseWTXID=false in the unit tests. This is used to construct a
CBlockHeaderAndShortTxIDs for a block with only the coinbase
transaction, so setting fUseWTXID to true or false makes no difference.
Suggested in https://github.com/bitcoin/bitcoin/pull/20799#pullrequestreview-963480278
fa587773e5 scripted-diff: Remove unused first argument to addUnchecked (MarcoFalke)
fe5c49766c tx pool: Use the entry's hash instead of the one passed to addUnchecked (MarcoFalke)
ddd395f968 Mark CTxMemPoolEntry members that should not be modified const (MarcoFalke)
Pull request description:
Several years ago the transaction hash was not cached. For optimization the hash was instead passed into `addUnchecked` to avoid re-calculating it. See f77654a0e9
Passing in the hash is now redundant and the argument can safely be removed.
Tree-SHA512: 0206b65c7a014295f67574120e8c5397bf1b1bd70c918ae1360ab093676f7f89a6f084fd2c7000a141baebfe63fe6f515559e38c4ac71810ba64f949f9c0467f
3fc20632a3 qt: Set BLOCK_CHAIN_SIZE = 220 (DrahtBot)
2b6a2f4a28 Regenerate manpages (DrahtBot)
eb7daf4d60 Update copyright headers to 2018 (DrahtBot)
Pull request description:
Some trivial maintenance to avoid having to do it again after the 0.17 branch off.
(The scripts to do this are in `./contrib/`)
Tree-SHA512: 16b2af45e0351b1c691c5311d48025dc6828079e98c2aa2e600dc5910ee8aa01858ca6c356538150dc46fe14c8819ed8ec8e4ec9a0f682b9950dd41bc50518fa
chain.h does not actually depend on the methods defined in pow.h, just its
include of consensus/params.h, which is standalone and can be included instead.
Confirmed by inspection and successful build.
