262ab8ef78 Add package evaluation fuzzer (Greg Sanders)
Pull request description:
This fuzzer target caught the issue in https://github.com/bitcoin/bitcoin/pull/28251 within 5 minutes on master branch, and an additional issue which I've applied a preliminary patch to cover.
Fuzzer target does the following:
1) Picks mempool confgs, including max package size, count, mempool size, etc
2) Generates 1 to 26 transactions with arbitrary coins/fees, the first N-1 spending only confirmed outpoints
3) Nth transaction, if >1, sweeps all unconfirmed outpoints in mempool
4) If N==1, it may submit it through single-tx submission path, to allow for more interesting topologies
5) Otherwise submits through package submission interface
6) Repeat 1-5 a few hundred times per mempool instance
In other words, it ends up building chains of txns in the mempool using parents-and-children packages, which is currently the topology supported on master.
The test itself is a direct rip of tx_pool.cpp, with a number of assertions removed because they were failing for unknown reasons, likely due to the notification changes of single tx submission to package, which is used to track addition/removal of transactions in the test. I'll continue working on re-adding these assertions for further invariant testing.
ACKs for top commit:
murchandamus:
ACK 262ab8ef78
glozow:
reACK 262ab8ef78
dergoegge:
tACK 262ab8ef78
Tree-SHA512: 190784777d0f2361b051b3271db8f79b7927e3cab88596d2c30e556da721510bd17f6cc96f6bb03403bbf0589ad3f799fa54e63c1b2bd92a2084485b5e3e96a5
6619d6a8dc