d273e53b6e bench/rpc_mempool: Create ChainTestingSetup, use its CTxMemPool (Carl Dong)
020caba3df bench: Use existing CTxMemPool in TestingSetup (Carl Dong)
86e732def3 scripted-diff: test: Use CTxMemPool in TestingSetup (Carl Dong)
213457e170 test/policyestimator: Use ChainTestingSetup's CTxMemPool (Carl Dong)
319f0ceeeb rest/getutxos: Don't construct empty mempool (Carl Dong)
03574b956a tree-wide: clang-format CTxMemPool references (Carl Dong)
Pull request description:
This is part of the `libbitcoinkernel` project: #24303, https://github.com/bitcoin/bitcoin/projects/18
This PR reduces the number of call sites where we explicitly construct CTxMemPool. This is done in preparation for later PRs which decouple the mempool module from `ArgsManager`, eventually all of libbitcoinkernel will be decoupled from `ArgsManager`.
The changes in this PR:
- Allows us to have less code churn as we modify `CTxMemPool`'s constructor in later PRs
- In many cases, we can make use of existing `CTxMemPool` instances, getting rid of extraneous constructions
- In other cases, we construct a `ChainTestingSetup` and use the `CTxMemPool` there, so that we can rely on the logic in `setup_common` to set things up correctly
## Notes for Reviewers
### A note on using existing mempools
When evaluating whether or not it's appropriate to use an existing mempool in a `*TestingSetup` struct, the key is to make sure that the mempool has the same lifetime as the `*TestingSetup` struct.
Example 1: In [`src/fuzz/tx_pool.cpp`](b4f686952a/src/test/fuzz/tx_pool.cpp), the `TestingSetup` is initialized in `initialize_tx_pool` and lives as a static global, while the `CTxMemPool` is in the `tx_pool_standard` fuzz target, meaning that each time the `tx_pool_standard` fuzz target gets run, a new `CTxMemPool` is created. If we were to use the static global `TestingSetup`'s CTxMemPool we might run into problems since its `CTxMemPool` will carry state between subsequent runs. This is why we don't modify `src/fuzz/tx_pool.cpp` in this PR.
Example 2: In [`src/bench/mempool_eviction.cpp`](b4f686952a/src/bench/mempool_eviction.cpp), we see that the `TestingSetup` is in the same scope as the constructed `CTxMemPool`, so it is safe to use its `CTxMemPool`.
### A note on checking `CTxMemPool` ctor call sites
After the "tree-wide: clang-format CTxMemPool references" commit, you can find all `CTxMemPool` ctor call sites with the following command:
```sh
git grep -E -e 'make_unique<CTxMemPool>' \
-e '\bCTxMemPool\s+[^({;]+[({]' \
-e '\bCTxMemPool\s+[^;]+;' \
-e '\bnew\s+CTxMemPool\b'
```
At the end of the PR, you will find that there are still quite a few call sites that we can seemingly get rid of:
```sh
$ git grep -E -e 'make_unique<CTxMemPool>' -e '\bCTxMemPool\s+[^({;]+[({]' -e '\bCTxMemPool\s+[^;]+;' -e '\bnew\s+CTxMemPool\b'
# rearranged for easier explication
src/init.cpp: node.mempool = std::make_unique<CTxMemPool>(node.fee_estimator.get(), mempool_check_ratio);
src/test/util/setup_common.cpp: m_node.mempool = std::make_unique<CTxMemPool>(m_node.fee_estimator.get(), 1);
src/rpc/mining.cpp: CTxMemPool empty_mempool;
src/test/util/setup_common.cpp: CTxMemPool empty_pool;
src/bench/mempool_stress.cpp: CTxMemPool pool;
src/bench/mempool_stress.cpp: CTxMemPool pool;
src/test/fuzz/rbf.cpp: CTxMemPool pool;
src/test/fuzz/tx_pool.cpp: CTxMemPool tx_pool_{/*estimator=*/nullptr, /*check_ratio=*/1};
src/test/fuzz/tx_pool.cpp: CTxMemPool tx_pool_{/*estimator=*/nullptr, /*check_ratio=*/1};
src/test/fuzz/validation_load_mempool.cpp: CTxMemPool pool{};
src/txmempool.h: /** Create a new CTxMemPool.
```
Let's break them down one by one:
```
src/init.cpp: node.mempool = std::make_unique<CTxMemPool>(node.fee_estimator.get(), mempool_check_ratio);
src/test/util/setup_common.cpp: m_node.mempool = std::make_unique<CTxMemPool>(m_node.fee_estimator.get(), 1);
```
Necessary
-----
```
src/rpc/mining.cpp: CTxMemPool empty_mempool;
src/test/util/setup_common.cpp: CTxMemPool empty_pool;
```
These are fixed in #25223 where we stop requiring the `BlockAssembler` to have a `CTxMemPool` if it's not going to consult it anyway (as is the case in these two call sites)
-----
```
src/bench/mempool_stress.cpp: CTxMemPool pool;
src/bench/mempool_stress.cpp: CTxMemPool pool;
```
Fixed in #24927.
-----
```
src/test/fuzz/rbf.cpp: CTxMemPool pool;
src/test/fuzz/tx_pool.cpp: CTxMemPool tx_pool_{/*estimator=*/nullptr, /*check_ratio=*/1};
src/test/fuzz/tx_pool.cpp: CTxMemPool tx_pool_{/*estimator=*/nullptr, /*check_ratio=*/1};
src/test/fuzz/validation_load_mempool.cpp: CTxMemPool pool{};
```
These are all cases where we don't want the `CTxMemPool` state to persist between runs, see the previous section "A note on using existing mempools"
-----
```
src/txmempool.h: /** Create a new CTxMemPool.
```
It's a comment (someone link me to a grep that understands syntax plz thx)
ACKs for top commit:
laanwj:
Code review ACK d273e53b6e
Tree-SHA512: c4ff3d23217a7cc4a7145defc7b901725073ef73bcac3a252ed75f672c87e98ca0368d1d8c3f606b5b49f641e7d8387d26ef802141b650b215876f191fb6d5f9
489b587669