32c1dd1ad6 [test] mempool coins disappearing mid-package evaluation (glozow)
a67f460c3f [refactor] split setup in mempool_limit test (glozow)
d08696120e [test framework] add ability to spend only confirmed utxos (glozow)
3ea71feb11 [validation] don't LimitMempoolSize in any subpackage submissions (glozow)
d227b7234c [validation] return correct result when already-in-mempool tx gets evicted (glozow)
9698b81828 [refactor] back-fill results in AcceptPackage (glozow)
8ad7ad3392 [validation] make PackageMempoolAcceptResult members mutable (glozow)
03b87c11ca [validation] add AcceptSubPackage to delegate Accept* calls and clean up m_view (glozow)
3f01a3dab1 [CCoinsViewMemPool] track non-base coins and allow Reset (glozow)
7d7f7a1189 [policy] check for duplicate txids in package (glozow)
Pull request description:
While we are evaluating a package, we split it into "subpackages" for evaluation (currently subpackages all have size 1 except the last one). If a subpackage has size 1, we may add a tx to mempool and call `LimitMempoolSize()`, which evicts transactions if the mempool gets full. We handle the case where the just-submitted transaction is evicted immediately, but we don't handle the case in which a transaction from a previous subpackage (either just submitted or already in mempool) is evicted. Mainly, since the coins created by the evicted transaction are cached in `m_view`, we don't realize the UTXO has disappeared until `CheckInputsFromMempoolAndCache` asserts that they exist. Also, the returned `PackageMempoolAcceptResult` reports that the transaction is in mempool even though it isn't anymore.
Fix this by not calling `LimitMempoolSize()` until the very end, and editing the results map with "mempool full" if things fall out.
Pointed out by instagibbs in faeed687e5 on top of the v3 PR.
ACKs for top commit:
instagibbs:
reACK 32c1dd1ad6
Tree-SHA512: 61e7f69db4712e5e5bfa27d037ab66bdd97f1bf60a8d9ffb96adb1f0609af012c810d681102ee5c7baec7b5fe8cb7c304a60c63ccc445d00d86a2b7f0e7ddb90
Temporary coins should not be available in separate subpackage submissions.
Any mempool coins that are cached in m_view should be removed whenever
mempool contents change, as they may be spent or no longer exist.
fb02ba3c5f mempool_entry: improve struct packing (Anthony Towns)
1a118062fb net_processing: Clean up INVENTORY_BROADCAST_MAX constants (Anthony Towns)
6fa49937e4 test: Check tx from disconnected block is immediately requestable (glozow)
e4ffabbffa net_processing: don't add txids to m_tx_inventory_known_filter (Anthony Towns)
6ec1809d33 net_processing: drop m_recently_announced_invs bloom filter (Anthony Towns)
a70beafdb2 validation: when adding txs due to a block reorg, allow immediate relay (Anthony Towns)
1e9684f39f mempool_entry: add mempool entry sequence number (Anthony Towns)
Pull request description:
This PR replaces the `m_recently_announced_invs` bloom filter with a simple sequence number tracking the mempool state when we last considered sending an INV message to a node. This saves 33kB per peer (or more if we raise the rate at which we relay transactions over the network, in which case we would need to increase the size of the bloom filter proportionally).
The philosophy here (compare with #18861 and #19109) is that we consider the rate limiting on INV messages to only be about saving bandwidth and not protecting privacy, and therefore after you receive an INV message, it's immediately fair game to request any transaction that was in the mempool at the time the INV message was sent. We likewise consider the BIP 133 feefilter and BIP 37 bloom filters to be bandwidth optimisations here, and treat transactions as requestable if they would have been announced without those filters. Given that philosophy, tracking the timestamp of the last INV message and comparing that against the mempool entry time allows removal of each of `m_recently_announced_invs`, `m_last_mempool_req` and `UNCONDITIONAL_RELAY_DELAY` and associated logic.
ACKs for top commit:
naumenkogs:
ACK fb02ba3c5f
amitiuttarwar:
review ACK fb02ba3c5f
glozow:
reACK fb02ba3c5f
Tree-SHA512: cbba5ee04c86df26b6057f3654c00a2b45ec94d354f4f157a769cecdaa0b509edaac02b3128afba39b023e82473fc5e28c915a787f84457ffe66638c6ac9c2d4
Rather than using a bloom filter to track announced invs, simply allow
a peer to request any tx that entered the mempool prior to the last INV
message we sent them. This also obsoletes the UNCONDITIONAL_RELAY_DELAY.
This is a refactor as long as no signed integer overflow appears. In
normal operation and absent bugs, signed integer overflow should never
happen in the touched code paths.
The main benefit of this refactor is to drop the file-wide ubsan
suppression unsigned-integer-overflow:txmempool.cpp.
For now, this only changes the internal private representation and the
publicly returned type remains uint64_t.
67b7fecacd [mempool] clear mapDeltas entry if prioritisetransaction sets delta to 0 (glozow)
c1061acb9d [functional test] prioritisation is not removed during replacement and expiry (glozow)
0e5874f0b0 [functional test] getprioritisedtransactions RPC (glozow)
99f8046829 [rpc] add getprioritisedtransactions (glozow)
9e9ca36c80 [mempool] add GetPrioritisedTransactions (glozow)
Pull request description:
Add an RPC to get prioritised transactions (also tells you whether the tx is in mempool or not), helping users clean up `mapDeltas` manually. When `CTxMemPool::PrioritiseTransaction` sets a delta to 0, remove the entry from `mapDeltas`.
Motivation / Background
- `mapDeltas` entries are never removed from mapDeltas except when the tx is mined in a block or conflicted.
- Mostly it is a feature to allow `prioritisetransaction` for a tx that isn't in the mempool {yet, anymore}. A user can may resbumit a tx and it retains its priority, or mark a tx as "definitely accept" before it is seen.
- Since #8448, `mapDeltas` is persisted to mempool.dat and loaded on restart. This is also good, otherwise we lose prioritisation on restart.
- Note the removal due to block/conflict is only done when `removeForBlock` is called, i.e. when the block is received. If you load a mempool.dat containing `mapDeltas` with transactions that were mined already (e.g. the file was saved prior to the last few blocks), you don't delete them.
- Related: #4818 and #6464.
- There is no way to query the node for not-in-mempool `mapDeltas`. If you add a priority and forget what the value was, the only way to get that information is to inspect mempool.dat.
- Calling `prioritisetransaction` with an inverse value does not remove it from `mapDeltas`, it just sets the value to 0. It disappears on a restart (`LoadMempool` checks if delta is 0), but that might not happen for a while.
Added together, if a user calls `prioritisetransaction` very regularly and not all those transactions get mined/conflicted, `mapDeltas` might keep lots of entries of delta=0 around. A user should clean up the not-in-mempool prioritisations, but that's currently difficult without keeping track of what those txids/amounts are.
ACKs for top commit:
achow101:
ACK 67b7fecacd
theStack:
Code-review ACK 67b7fecacd
instagibbs:
code review ACK 67b7fecacd
ajtowns:
ACK 67b7fecacd code review only, some nits
Tree-SHA512: 9df48b622ef27f33db1a2748f682bb3f16abe8172fcb7ac3c1a3e1654121ffb9b31aeaad5570c4162261f7e2ff5b5912ddc61a1b8beac0e9f346a86f5952260a
Since the kernel library no longer depends on the system file, move it
to the common library instead in accordance to the diagram in
doc/design/libraries.md.
6b605b91c1 [fuzz] Add MiniMiner target + diff fuzz against BlockAssembler (glozow)
3f3f2d59ea [unit test] GatherClusters and MiniMiner unit tests (glozow)
59afcc8354 Implement Mini version of BlockAssembler to calculate mining scores (glozow)
56484f0fdc [mempool] find connected mempool entries with GatherClusters(…) (glozow)
Pull request description:
Implement Mini version of BlockAssembler to calculate mining scores
Run the mining algorithm on a subset of the mempool, only disturbing the
mempool to copy out fee information for relevant entries. Intended to be
used by wallet to calculate amounts needed for fee-bumping unconfirmed
transactions.
From comments of sipa and glozow below:
> > In what way does the code added here differ from the real block assembly code?
>
> * Only operates on the relevant transactions rather than full mempool
> * Has the ability to remove transactions that will be replaced so they don't impact their ancestors
> * Does not hold mempool lock outside of the constructor, makes copies of the entries it needs instead (though I'm not sure if this has an effect in practice)
> * Doesn't do the sanity checks like keeping weight within max block weight and `IsFinalTx()`
> * After the block template is built, additionally calculates fees to bump remaining ancestor packages to target feerate
ACKs for top commit:
achow101:
ACK 6b605b91c1
Xekyo:
> ACK [6b605b9](6b605b91c1) modulo `miniminer_overlap` test.
furszy:
ACK 6b605b91 modulo `miniminer_overlap` test.
theStack:
Code-review ACK 6b605b91c1
Tree-SHA512: f86a8b4ae0506858a7b15d90f417ebceea5038b395c05c825e3796123ad3b6cb8a98ebb948521316802a4c6d60ebd7041093356b1e2c2922a06b3b96b3b8acb6
It's unnecessary to keep the data around, as it doesn't do anything. If
prioritisetransaction is called again, we'll make a new entry in
mapDeltas.
These entries are only deleted when the transaction is mined or conflicted
from a block (i.e. not in replacement or eviction), are persisted in
mempool.dat, and never expire. If node operators use the RPC to
regularly prioritise/de-prioritise transactions, these (meaningless)
map entries may hang around forever and take up valuable mempool memory.
We use CompareDepthAndScore to choose an order of txs to inv. Rather
than sorting txs that have been evicted from the mempool at the end
of the list, sort them at the beginning so they are removed from
the queue immediately.
This is an extraction of ArgsManager related functions from util/system
into their own common file.
Config file related functions are moved to common/config.cpp.
The background of this commit is an ongoing effort to decouple the
libbitcoinkernel library from the ArgsManager. The ArgsManager belongs
into the common library, since the kernel library should not depend on
it. See doc/design/libraries.md for more information on this rationale.
We limit GatherClusters’s result to a maximum of 500 transactions as
clusters can be made arbitrarily large by third parties.
Co-authored-by: Murch <murch@murch.one>
4b7aec2951 Add mempool tracepoints (virtu)
Pull request description:
This PR adds multiple mempool tracepoints.
| tracepoint | description |
| ------------- | ------------- |
| `mempool:added` | Is called when a transaction enters the mempool |
| `mempool:removed` | ... when a transaction is removed from the mempool |
| `mempool:replaced` | ... when a transaction is replaced in the mempool |
| `mempool:rejected` | ... when a transaction is rejected from entering the mempool |
The tracepoints are further documented in `docs/tracing.md`. Usage is demonstrated in the example script `contrib/tracing/mempool_monitor.py`. Interface tests are provided in `test/functional/interface_usdt_mempool.py`.
The rationale for passing the removal reason as a string instead of numerically is that the benefits of not having to maintain a redundant enum-string mapping seem to outweigh the small cost of string generation. The reject reason is passed as string as well, although in this instance the string does not have to be generated but is readily available.
ACKs for top commit:
0xB10C:
ACK 4b7aec2951
achow101:
ACK 4b7aec2951
Tree-SHA512: 6deb3ba2d1a061292fb9b0f885f7a5c4d11b109b838102d8a8f4828cd68f5cd03fa3fc64adc6fdf54a08a1eaccce261b0aa90c2b8c33cd5fd3828c8f74978958
Tracepoints for added, removed, replaced, and rejected transactions.
The removal reason is passed as string instead of a numeric value, since
the benefits of not having to maintain a redundant enum-string mapping
seem to outweigh the small cost of string generation. The reject reason
is passed as string as well, although here the string does not have to
be generated but is readily available.
So far, tracepoint PRs typically included two demo scripts: a naive
bpftrace script to show raw tracepoint data and a bcc script for a more
refined view. However, as some of the ongoing changes to bpftrace
introduce a certain degree of unreliability (running some of the
existing bpftrace scripts was not possible with standard kernels and
bpftrace packages on latest stable Ubuntu, Debian, and NixOS), this PR
includes only a single bcc script that fuses the functionality of former
bpftrace and bcc scripts.
fa818e103c txmempool: Remove unused clear() member function (MarcoFalke)
Pull request description:
Seems odd to have code in Bitcoin Core that is unused.
Moreover the function was broken (see https://github.com/bitcoin/bitcoin/pull/24145) and is brittle, as there is nothing that prevents similar bugs from re-appearing.
Fix both issues by replacing it with C++11 member initializers.
ACKs for top commit:
glozow:
ACK fa818e103c
Tree-SHA512: e79e44cac7d5a84d9ecc8e3f3b0b9a50e1e3ebec358b20ba5dac175ef07d1fbe338a20f83ee80f746f7c726c79e77f8be49e14bca57a41063da8a5302123c3a9
47c4b1f52a mempool: log/halt when CalculateMemPoolAncestors fails unexpectedly (stickies-v)
5481f65849 mempool: add AssumeCalculateMemPoolAncestors helper function (stickies-v)
f911bdfff9 mempool: use util::Result for CalculateMemPoolAncestors (stickies-v)
66e028f739 mempool: use util::Result for CalculateAncestorsAndCheckLimits (stickies-v)
Pull request description:
Upon reviewing the documentation for `CTxMemPool::CalculateMemPoolAncestors`, I noticed `setAncestors` was meant to be an `out` parameter but actually is an `in,out` parameter, as can be observed by adding `assert(setAncestors.empty());` as the first line in the function and running `make check`. This PR fixes this unexpected behaviour and introduces refactoring improvements to make intents and effects of the code more clear.
## Unexpected behaviour
This behaviour occurs only in the package acceptance path, currently only triggered by `testmempoolaccept` and `submitpackage` RPCs.
In `MemPoolAccept::AcceptMultipleTransactions()`, we first call `PreChecks()` and then `SubmitPackage()` with the same `Workspace ws` reference. `PreChecks` leaves `ws.m_ancestors` in a potentially non-empty state, before it is passed on to `MemPoolAccept::SubmitPackage`. `SubmitPackage` is the only place where `setAncestors` isn't guaranteed to be empty before calling `CalculateMemPoolAncestors`. The most straightforward fix is to just forcefully clear `setAncestors` at the beginning of CalculateMemPoolAncestors, which is done in the first bugfix commit.
## Improvements
### Return value instead of out-parameters
This PR updates the function signatures for `CTxMemPool::CalculateMemPoolAncestors` and `CTxMemPool::CalculateAncestorsAndCheckLimits` to use a `util::Result` return type and eliminate both the `setAncestors` `in,out`-parameter as well as the error string. It simplifies the code and makes the intent and effects more explicit.
### Observability
There are 7 instances where we currently call `CalculateMemPoolAncestors` without actually checking if the function succeeded because we assume that it can't fail, such as in [miner.cpp](69b10212ea/src/node/miner.cpp (L399)). This PR adds a new wrapper `AssumeCalculateMemPoolAncestors` function that logs such unexpected failures, or in case of debug builds even halts the program. It's not crucial to the objective, more of an observability improvement that seems sensible to add on here.
ACKs for top commit:
achow101:
ACK 47c4b1f52a
w0xlt:
ACK 47c4b1f52a
glozow:
ACK 47c4b1f52a
furszy:
light code review ACK 47c4b1f5
aureleoules:
ACK 47c4b1f52a
Tree-SHA512: d908dad00d1a5645eb865c4877cc0bae74b9cd3332a3641eb4a285431aef119f9fc78172d38b55c592168a73dae83242e6af3348815f7b37cbe2d448a3a58648
When CalculateMemPoolAncestors fails unexpectedly (e.g. it exceeds
ancestor/descendant limits even though we expect no limits to be applied),
add an error log entry for increased visibility. For debug builds,
the application will even halt completely since this is not supposed
to happen.
There are quite a few places that assume CalculateMemPoolAncestors
will return a value without raising an error. This helper function
adds logging (and Assume for debug builds) that ensures robustness
but increases visibility in case of unexpected failures
c8dc0e3eaa refactor: Inline `CTxMemPoolEntry` class's functions (Hennadii Stepanov)
75bbe594e5 refactor: Move `CTxMemPoolEntry` class to its own module (Hennadii Stepanov)
Pull request description:
This PR:
- gets rid of the `policy/fees` -> `txmempool` -> `policy/fees` circular dependency
- is an alternative to #13949, which nukes only one circular dependency
ACKs for top commit:
ryanofsky:
Code review ACK c8dc0e3eaa. Just include and whitespace changes since last review, and there's a moveonly commit now so it's very easy to review
theStack:
Code-review ACK c8dc0e3eaa
glozow:
utACK c8dc0e3eaa, agree these changes are an improvement.
Tree-SHA512: 36ece824e6ed3ab1a1e198b30a906c8ac12de24545f840eb046958a17315ac9260c7de26e11e2fbab7208adc3d74918db7a7e389444130f8810548ca2e81af41
Currently the exact reason a transaction is removed from the mempool isn't
logged. It is sometimes detectable from context, but adding the `reason` to
the validation interface logs (where it is already passed) seems like an easy
way to disambiguate.
For example, in the case of mempool expiry, the logs look like this:
```
[validationinterface.cpp:220] [TransactionRemovedFromMempool] [validation] Enqueuing TransactionRemovedFromMempool: txid=<txid> wtxid=<wtxid>
[txmempool.cpp:1050] [RemoveUnbroadcastTx] [mempool] Removed <txid> from set of unbroadcast txns before confirmation that txn was sent out
[validationinterface.cpp:220] [operator()] [validation] TransactionRemovedFromMempool: txid=<txid> wtxid=<wtxid>
[validation.cpp:267] [LimitMempoolSize] [mempool] Expired 1 transactions from the memory pool
```
There is no context-free way to know $txid was evicted on the basis of expiry.
This change will make that case (and probably others) clear.
33b12e5df6 docs: improve docs where MemPoolLimits is used (stickies-v)
6945853c0b test: use NoLimits() in MempoolIndexingTest (stickies-v)
3a86f24a4c refactor: mempool: use CTxMempool::Limits (stickies-v)
b85af25f87 refactor: mempool: add MemPoolLimits::NoLimits() (stickies-v)
Pull request description:
Mempool currently considers 4 limits regarding ancestor and descendant count and size, which get passed around between functions quite a bit. This PR uses `CTxMemPool::Limits` introduced in https://github.com/bitcoin/bitcoin/pull/25290 to simplify those signatures and callsites.
The purpose of this PR is to improve readability and maintenance, without behaviour change.
As noted in the first commit "refactor: mempool: change MemPoolLimits members to uint", we currently have an underflow issue where a user could pass a negative `-limitancestorsize`, which is eventually cast to an unsigned integer. This behaviour already exists. Because it's orthogonal and to minimize scope, I think this should be fixed in a separate PR.
ACKs for top commit:
hebasto:
ACK 33b12e5df6, I have reviewed the code and it looks OK, I agree it can be merged.
glozow:
reACK 33b12e5df6
Tree-SHA512: 591c6dcee1894f1c3ca28b34a680eeadcf0d40cda92451b4a422c03087b27d682b5e30ba4367abd75a99b5ccb115b7884b0026958d3c7dddab030549db5a4056
Simplifies function signatures by removing repetition of all the
ancestor/descendant limits, and increases readability by being
more verbose by naming the limits, while still reducing the LoC.
m_is_loaded/IsLoaded() doesn't actually indicate whether or not the
mempool was successfully, loaded, but rather if a load has been
attempted and did not result in a catastrophic ShutdownRequested.
-BEGIN VERIFY SCRIPT-
find_regex="\bm_is_loaded\b" \
&& git grep -l -E "$find_regex" \
| xargs sed -i -E "s@$find_regex@m_load_tried@g"
find_regex="\bIsLoaded\b" \
&& git grep -l -E "$find_regex" \
| xargs sed -i -E "s@$find_regex@GetLoadTried@g"
find_regex="\bSetIsLoaded\b" \
&& git grep -l -E "$find_regex" \
| xargs sed -i -E "s@$find_regex@SetLoadTried@g"
-END VERIFY SCRIPT-
This new node policy setting enables to accept replaced-by-fee
transaction without inspection of the replaceability signaling
as described in BIP125 "explicit signaling".
If turns on, the node mempool accepts transaction replacement
as described in `policy/mempool-replacements.md`.
The default setting value is `false`, implying opt-in RBF
is enforced.
d1684beabe fees: Pass in a filepath instead of referencing gArgs (Carl Dong)
9a3d825c30 init: Remove redundant -*mempool*, -limit* queries (Carl Dong)
6c5c60c412 mempool: Use m_limit for UpdateTransactionsFromBlock (Carl Dong)
9e93b10301 node/ifaces: Use existing MemPoolLimits (Carl Dong)
38af2bcf35 mempoolaccept: Use limits from mempool in constructor (Carl Dong)
9333427014 mempool: Introduce (still-unused) MemPoolLimits (Carl Dong)
716bb5fbd3 scripted-diff: Rename anc/desc size limit vars to indicate SI unit (Carl Dong)
1ecc77321d scripted-diff: Rename DEFAULT_MEMPOOL_EXPIRY to indicate time unit (Carl Dong)
aa9141cd81 mempool: Pass in -mempoolexpiry instead of referencing gArgs (Carl Dong)
51c7a41a5e init: Only determine maxmempool once (Carl Dong)
386c9472c8 mempool: Make GetMinFee() with custom size protected (Carl Dong)
82f00de7a6 mempool: Pass in -maxmempool instead of referencing gArgs (Carl Dong)
f1941e8bfd pool: Add and use MemPoolOptions, ApplyArgsManOptions (Carl Dong)
0199bd35bb fuzz/rbf: Add missing TestingSetup (Carl Dong)
ccbaf546a6 scripted-diff: Rename DEFAULT_MAX_MEMPOOL_SIZE to indicate SI unit (Carl Dong)
fc02f77ca6 ArgsMan: Add Get*Arg functions returning optional (Carl Dong)
Pull request description:
This is part of the `libbitcoinkernel` project: #24303, https://github.com/bitcoin/bitcoin/projects/18
-----
As mentioned in the Stage 1 Step 2 description of [the `libbitcoinkernel` project](https://github.com/bitcoin/bitcoin/issues/24303), `ArgsManager` will not be part of `libbitcoinkernel`. Therefore, it is important that we remove any dependence on `ArgsManager` by code that will be part of `libbitcoinkernel`. This is the first in a series of PRs aiming to achieve this.
This PR removes `CTxMemPool+MempoolAccept`'s dependency on `ArgsManager` by introducing a `CTxMemPool::Options` struct, which is used to specify `CTxMemPool`'s various options at construction time.
These options are:
- `-maxmempool` -> `CTxMemPool::Options::max_size`
- `-mempoolexpiry` -> `CTxMemPool::Options::expiry`
- `-limitancestorcount` -> `CTxMemPool::Options::limits::ancestor_count`
- `-limitancestorsize` -> `CTxMemPool::Options::limits::ancestor_size`
- `-limitdescendantcount` -> `CTxMemPool::Options::limits::descendant_count`
- `-limitdescendantsize` -> `CTxMemPool::Options::limits::descendant_size`
More context can be gleaned from the commit messages. The important commits are:
- 56eb479ded8bfb2ef635bb6f3b484f9d5952c70d "pool: Add and use MemPoolOptions, ApplyArgsManOptions"
- a1e08b70f3068f4e8def1c630d8f50cd54da7832 "mempool: Pass in -maxmempool instead of referencing gArgs"
- 6f4bf3ede5812b374828f08fc728ceded2f10024 "mempool: Pass in -mempoolexpiry instead of referencing gArgs"
- 5958a7fe4806599fc620ee8c1a881ca10fa2dd16 "mempool: Introduce (still-unused) MemPoolLimits"
Reviewers: Help needed in the following commits (see commit messages):
- a1e08b70f3068f4e8def1c630d8f50cd54da7832 "mempool: Pass in -maxmempool instead of referencing gArgs"
- 0695081a797e9a5d7787b78b0f8289dafcc6bff7 "node/ifaces: Use existing MemPoolLimits"
Note to Reviewers: There are perhaps an infinite number of ways to architect `CTxMemPool::Options`, the current one tries to keep it simple, usable, and flexible. I hope we don't spend too much time arguing over the design here since that's not the point. In the case that you're 100% certain that a different design is strictly better than this one in every regard, please show us a fully-implemented branch.
-----
TODO:
- [x] Use the more ergonomic `CTxMemPool::Options` where appropriate
- [x] Doxygen comments for `ApplyArgsManOptions`, `MemPoolOptions`
-----
Questions for Reviewers:
1. Should we use `std::chrono::seconds` for `CTxMemPool::Options::expiry` and `CTxMemPool::m_expiry` instead of an `int64_t`? Something else? (`std::chrono::hours`?)
2. Should I merge `CTxMemPool::Limits` inside `CTxMemPool::Options`?
ACKs for top commit:
MarcoFalke:
ACK d1684beabe🍜
ryanofsky:
Code review ACK d1684beabe. Just minor cleanups since last review, mostly switching to brace initialization
Tree-SHA512: 2c138e52d69f61c263f1c3648f01c801338a8f576762c815f478ef5148b8b2f51e91ded5c1be915e678c0b14f6cfba894b82afec58d999d39a7bb7c914736e0b
