This commit only declares constants without using them. They will be applied in
seperate commit since changing struct default field values in cap'n proto is
not backwards compatible.
libmultiprocess currently handles uncaught exceptions from IPC methods badly
when an `mp.Context` parameter is passed and the IPC call executes on an a
worker thread, with the uncaught exception leading to a std::terminate call.
https://github.com/bitcoin-core/libmultiprocess/pull/218 was created to fix
this, but before that change is available, update an IPC test which can trigger
this behavior to handle it and recover when mp.Context parameters are added in
the an upcoming commit.
Having this workaround makes the test a little more complicated and less strict
but reduces dependencies between pending PRs so they don't need to be reviewed
or merged in a particular order.
Allow `expected_stderr` option passed to `wait_until_stopped` and
`is_node_stopped` helper functions to be a regex pattern instead of just a
fixed string.
Allow `expected_ret_code` be list of possible exit codes instead of a single
error code to handle the case where exit codes vary depending on OS and libc.
b623fab1ba87ea93dd7e302b8c927e55f2036173 mining: enforce minimum reserved weight for IPC (Sjors Provoost)
d3e49528d479613ebe50088d530a621861463fa4 mining: fix -blockreservedweight shadows IPC option (Sjors Provoost)
418b7995ddfbc88764f1f0ceabf8993808b08bd8 test: have mining template helpers return None (Sjors Provoost)
Pull request description:
Also enforce `MINIMUM_BLOCK_RESERVED_WEIGHT` for IPC clients.
The `-blockreservedweight` startup option should only affect RPC code, because IPC clients (currently) do not have a way to signal their intent to use the node default (the `BlockCreateOptions` struct defaults merely document a recommendation for client software).
Before this PR however, if the user set `-blockreservedweight` then `ApplyArgsManOptions` would cause the `block_reserved_weight` option passed by IPC clients to be ignored. _Users who don't set this value were not affected._
Fix this by making BlockCreateOptions::block_reserved_weight an std::optional.
Internal interface users, such as the RPC call sites, don't set a value so -blockreservedweight is used. Whereas IPC clients do set a value which is no longer ignored.
Test coverage is added, with a preliminary commit that refactors the `create_block_template` and `wait_next_template` helpers.
`mining_basic.py` already ensured `-blockreservedweight` is enforced by mining RPC methods. The second commit adds coverage for Mining interface IPC clients. It also verifies that `-blockreservedweight` has no effect on them.
The third commit enforces `MINIMUM_BLOCK_RESERVED_WEIGHT` for IPC clients. Previously lower values were quietly clamped.
---
Merge order preference: #34452 should ideally go first.
ACKs for top commit:
sedited:
Re-ACK b623fab1ba87ea93dd7e302b8c927e55f2036173
ryanofsky:
Code review ACK b623fab1ba87ea93dd7e302b8c927e55f2036173. Was rebased and test split up and comment updated since last review.
ismaelsadeeq:
ACK b623fab1ba87ea93dd7e302b8c927e55f2036173
Tree-SHA512: 9e651a520d8e4aeadb330da86788744b6ecad8060fa21d50dc8e6012a60083e7b262aaa08a64676b9ef18ba65b651bc1272d8383d184030342e4c0f2c6a9866d
65134c7e5f99500baed18d575b576e33a6294ecf depends: Prefix include path for headers-only `systemtap` package (Hennadii Stepanov)
94a692b6aa09d2e5df97bbc9cc810854818f9333 cmake: Add missed `USDT::headers` (Hennadii Stepanov)
b5375c44ed16ed6aae3d46ac6316b3981330f100 depends: Prefix include path for headers-only `boost` package (Hennadii Stepanov)
d73378ffcca2de43a79c4903221e8164cf256469 cmake: Add missed `Boost::headers` (Hennadii Stepanov)
Pull request description:
Currently, header-only dependencies in the depends subsystem are installed into the standard `include/` subdirectory. This inadvertently exposes their headers to the compiler via `-I` flags brought in by other dependencies (e.g., `libevent` or `sqlite`). This "include path pollution" masks missing dependencies in the build configuration. While the build might succeed by accident due to this overlap, it creates a fragile state. If the overlapping library is removed, the build will break, or, worse, the compiler may silently fall back to the host system's default paths (e.g., `/usr/include`).
This PR improves build system security and hygiene by enforcing strict, distinguished include paths for header-only dependencies. The missing dependencies revealed by this change (`Boost::headers`, `USDT::headers`) have been fixed in separate commits.
ACKs for top commit:
theuni:
re-ACK 65134c7e5f99500baed18d575b576e33a6294ecf
fanquake:
ACK 65134c7e5f99500baed18d575b576e33a6294ecf
Tree-SHA512: 41667b46c3bd2f872951a5651b30f7d1468f49f1265196b7868233ed44b2eb0e33f1f69a1af348b55f07a8d1f594e276eb49b724e80b8eae85aed1c9bacae197
6f113cb1847c6890f1fbd052ff7eb8ea41ccafc5 txgraph: use fallback order to sort chunks (feature) (Pieter Wuille)
0a3351947e736c646a6dfffef24b83d003c569e7 txgraph: use fallback order when linearizing (feature) (Pieter Wuille)
fba004a3df02d8d5d47f1ad0bb1ccbfde01bb2af txgraph: pass fallback_order to TxGraph (preparation) (Pieter Wuille)
941c432a4637efd4e5040259f47f2bfed073af7c txgraph test: subclass TxGraph::Ref like mempool does (preparation) (Pieter Wuille)
39d0052cbf478a729ae0288262003bba9c12690b clusterlin: make optimal linearizations deterministic (feature) (Pieter Wuille)
8bfbba32077cb8682208ef31748a10562be027db txgraph: sort distinct-cluster chunks by equal-feerate-prefix size (feature) (Pieter Wuille)
e0bc73ba9270b860d81e479a7bddcff8cfd8bfb6 clusterlin: sort tx in chunk by feerate and size (feature) (Pieter Wuille)
6c1bcb2c7c1a0017562e99195d74c3a05444633b txgraph: clear cluster's chunk index in ~Ref (preparation) (Pieter Wuille)
7427c7d0983050543f1fc7863121d8e2bf4b1511 txgraph: update chunk index on Compact (preparation) (Pieter Wuille)
3ddafceb9afd9d493b927bc91dae324225ed8e32 txgraph: initialize Ref in AddTransaction (preparation) (Pieter Wuille)
Pull request description:
Part of #30289.
TxGraph's fundamental responsibility is deciding the order of transactions in the mempool. It relies on the `cluster_linearize.h` code to optimize it, but there can and often will be many different orderings that are essentially equivalent from a quality perspective, so we have to pick one. At a high level, the solution will involve one or more of:
* Deciding based on **internal identifiers** (`Cluster::m_sequence`, `DepGraphIndex`). This is very simple, but risks leaking information about transaction receive order.
* Deciding **randomly**, which is private, but may interfere with relay expectations, block propagation, and ability to monitor network behavior.
* Deciding **based on txid**, which is private and deterministic, but risks incentivizing grinding to get an edge (though we haven't really seen such behavior).
* Deciding **based on size** (e.g. prefer smaller transactions), which is somewhat related to quality, but not unconditionally (depending on mempool layout, the ideal ordering might call for smaller transactions first, last, or anywhere in between). It's also not a strong ordering as there can be many identically-sized transactions. However, if it were to encourage grinding behavior, incentivizing smaller transactions is probably not a bad thing.
As of #32545, the current behavior is primarily picking randomly, though inconsistently, as some code paths also use internal identifiers and size. #33335 sought to change it to use random (preferring size in a few places), with the downsides listed above.
This PR is an alternative to that, which changes the order to tie-break based on size everywhere possible, and use lowest-txid-first as final fallback. This is fully deterministic: for any given set of mempool transactions, if all linearized optimally, the transaction order exposed by TxGraph is deterministic.
The transactions within a chunk are sorted according to:
1. `PostLinearize` (which improves sub-chunk order), using an initial linearization created using the rules 2-5 below.
2. Topology (parents before children).
3. Individual transaction feerate (high to low)
4. Individual transaction weight (small to large)
5. Txid (low to high txid)
The chunks within a cluster are sorted according to:
1. Topology (chunks after their dependencies)
2. Chunk feerate (high to low)
3. Chunk weight (small to large)
4. Max-txid (chunk with lowest maximum-txid first)
The chunks across clusters are sorted according to:
1. Feerate (high to low)
2. Equal-feerate-chunk-prefix weight (small to large)
3. Max-txid (chunk with lowest maximum-txid first)
The equal-feerate-chunk-prefix weight of a chunk C is defined as the sum of the weights of all chunks in the same cluster as C, with the same feerate as C, up to and including C itself, in linearization order (but excluding such chunks that appear after C). This is a well-defined approximation of sorting chunks from small to large across clusters, while remaining consistent with intra-cluster linearization order.
ACKs for top commit:
ajtowns:
reACK 6f113cb1847c6890f1fbd052ff7eb8ea41ccafc5 it was good before and now it's better
instagibbs:
ACK 6f113cb1847c6890f1fbd052ff7eb8ea41ccafc5
marcofleon:
light crACK 6f113cb1847c6890f1fbd052ff7eb8ea41ccafc5
Tree-SHA512: 16dc43c62b7e83c81db1ee14c01e068ae2f06c1ffaa0898837d87271fa7179dd98baeb74abc9fe79220e01fdba6876defe60022c2b72badc21d770644a0fe0ac
38fd85c676a072ebf256e806beda9d7533790baa http: replace WorkQueue and threads handling for ThreadPool (furszy)
c323f882ed3841401edee90ab5261d68215ab316 fuzz: add test case for threadpool (TheCharlatan)
c528dd5f8ccc3955b00bdba869f0a774efa97fe1 util: introduce general purpose thread pool (furszy)
6354b4fd7fe819eb13274b212e426a7d10ca75d3 tests: log node JSON-RPC errors during test setup (furszy)
45930a79412dc45f9d391cd7689d029fa4f0189e http-server: guard against crashes from unhandled exceptions (furszy)
Pull request description:
This has been a recent discovery; the general thread pool class created for #26966, cleanly
integrates into the HTTP server. It simplifies init, shutdown and requests execution logic.
Replacing code that was never unit tested for code that is properly unit and fuzz tested.
Although our functional test framework extensively uses this RPC interface (that’s how
we’ve been ensuring its correct behavior so far - which is not the best).
This clearly separates the responsibilities:
The HTTP server now focuses solely on receiving and dispatching requests, while ThreadPool handles
concurrency, queuing, and execution.
This will also allows us to experiment with further performance improvements at the task queuing and
execution level, such as a lock-free structure or task prioritization or any other implementation detail
like coroutines in the future, without having to deal with HTTP code that lives on a different layer.
Note:
The rationale behind introducing the ThreadPool first is to be able to easily cherry-pick it across different
working paths. Some of the ones that are benefited from it are #26966 for the parallelization of the indexes
initial sync, #31132 for the parallelization of the inputs fetching procedure, #32061 for the libevent replacement,
the kernel API #30595 (https://github.com/bitcoin/bitcoin/pull/30595#discussion_r2413702370) to avoid blocking validation among others use cases not publicly available.
Note 2:
I could have created a wrapper around the existing code and replaced the `WorkQueue` in a subsequent
commit, but it didn’t seem worth the extra commits and review effort. The `ThreadPool` implements
essentially the same functionality in a more modern and cleaner way.
ACKs for top commit:
Eunovo:
ReACK 38fd85c676
sedited:
Re-ACK 38fd85c676a072ebf256e806beda9d7533790baa
pinheadmz:
ACK 38fd85c676a072ebf256e806beda9d7533790baa
Tree-SHA512: a0330e54ed504330ca874c42d4e318a909f548b2fb9ac46db8badf5935b9eec47dc4ed503d1b6f98574418e3473420ea45f60498be05545c4325cfa89dcca689
The function signature for the `send` RPC is:
```
send [{"address":amount,...},{"data":"hex"},...] ( conf_target "estimate_mode" fee_rate options version )
```
The last example in the manpage is missing the `fee_rate` arg, but is trying to specify the `options` arg, by index.
The parser confuses the intended `options` arg as the missing `fee_rate` arg.
See:
```
$ bitcoin-cli -rpcuser=doggman -rpcpassword=donkey -rpcport=18554 -regtest send '{"bcrt1qusm48zmlzwr32csxdw4ar7atw260h22c9ten9l": 0.1}' 1 economical '{"add_to_wallet": false, "inputs": [{"txid":"0b7e1a471dc948b7a6187936b16e6d7d9833629b2f9dd8a392eb89928f63aaad", "vout":0}]}'
error code: -8
error message:
Cannot specify both conf_target and fee_rate. Please provide either a confirmation target in blocks for automatic fee estimation, or an explicit fee rate.
```
vs
```
$ bitcoin-cli -rpcuser=doggman -rpcpassword=donkey -rpcport=18554 -regtest send '{"bcrt1qusm48zmlzwr32csxdw4ar7atw260h22c9ten9l": 0.1}' 1 economical null '{"add_to_wallet": false, "inputs": [{"txid":"0b7e1a471dc948b7a6187936b16e6d7d9833629b2f9dd8a392eb89928f63aaad", "vout":0}]}'
{
"psbt": "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",
"txid": "625b71b314a6ac4f738634e29dc007cd5edc0427c1ae96ab706d06a62910cea2",
"hex": "02000000000101adaa638f9289eb92a3d89d2f9b6233987d6d6eb1367918a6b748c91d471a7e0b0000000000fdffffff0244760f0400000000160014a4b0f026efb01511cb40080a01bd29b24ed455dd8096980000000000160014e437538b7f13871562066babd1fbab72b4fba9580247304402204953578a5b52bb0f47da8759c8a8a3056fdd05561e2cf1c1ebdf0f4bbf23c6320220426373b317cd4f48b334d21e2e79091e858bb10c566eec9939d627a3a612a79f012103454a758552c81a56a310704c33aea41e7c162de6101b3ebbe38ea84615776b1900000000",
"complete": true
}
```
- Introduce a `FeeRateFormat` enum and change `CFeeRate::ToString()`
to use it for `BTC/kvB` vs `sat/vB` output formatting.
- Handle all enum values, hence remove default case in `CFeeRate::ToString()`
and `assert(False)` when a `FeeRateFormat` value is not handled.
- Keep `FeeEstimateMode` focused on fee estimation behavior by removing fee rate format
values from `FeeEstimateMode`.
- Update all formatting call sites and tests to pass `FeeRateFormat` explicitly, separating fee rate format
from fee-estimation mode selection.
The vcpkg tools cache was using the combined actions/cache action,
which saves on every run regardless of branch. Split it into the
restore/save pattern used by the other caches, so that saves only
happen on default branch pushes.
2ccfdb582b646d9bda07f0f13b97cb8c37a452aa build: avoid exporting secp256k1 symbols (Cory Fields)
Pull request description:
Take advantage of the [new secp256k1 option to avoid visibility attributes](https://github.com/bitcoin-core/secp256k1/pull/1696) on API functions.
While most users of a shared libsecp always want API functions exported so that they can actually be linked against, we always build it statically. When that static lib is linked into a (static or shared) libbitcoinkernel, by default its symbols end up exported there as well.
As libsecp is an implementation detail of the kernel (and any future Core lib), its symbols should never be exported.
[This was the intended use for the above PR](https://github.com/bitcoin-core/secp256k1/pull/1696#issuecomment-3028838988), looks like we just forgot to follow-up and actually hook it up.
This is most easily tested by building with `-DBUILD_KERNEL_LIB=ON -DBUILD_SHARED_LIBS=ON` (with or without `-DREDUCE_EXPORTS=ON`) and inspecting via:
```bash
nm -CD lib/libbitcoinkernel.so | grep secp
```
Before this change, secp's symbols will show up there. After, they should be absent.
This should finally solve secp symbol visibility once and for all :)
ACKs for top commit:
hebasto:
ACK 2ccfdb582b646d9bda07f0f13b97cb8c37a452aa, this is implemented exactly as I [tested](https://github.com/bitcoin-core/secp256k1/pull/1696#pullrequestreview-3033584362) the upstream PR. Tested on Fedora 43.
stickies-v:
tACK 2ccfdb582b646d9bda07f0f13b97cb8c37a452aa
Tree-SHA512: 664ea7a6f811c2743ad1b4d8913c61aab9b358931ee77895d35cdf8a5607fbb08facda085877c53d731afbf42a7220dcc752fc365a7625ee679c1547e1c674d0
452c743951fa69f25f09e42239d1e70a0acf5c2b refactor: Remove workaround for resolved MSVC bug (Hennadii Stepanov)
7164a0cab650bdf01cdcbc3da690f6b674fcc7b3 build: Bump VS minimum supported version to 18.3 (Hennadii Stepanov)
Pull request description:
The new [VS 18.0](https://learn.microsoft.com/en-us/visualstudio/releases/2026/release-notes) release includes numerous bug fixes.
Bumped to v18.3.0 where [this](https://github.com/microsoft/vcpkg/issues/22074) bug in the builtin vcpkg is [fixed](https://github.com/microsoft/vcpkg/issues/22074#issuecomment-3880320585).
ACKs for top commit:
maflcko:
review ACK 452c743951fa69f25f09e42239d1e70a0acf5c2b 🍳
hodlinator:
crACK 452c743951fa69f25f09e42239d1e70a0acf5c2b
janb84:
ACK 452c743951fa69f25f09e42239d1e70a0acf5c2b
Tree-SHA512: a8f859d11d4cf0440cf7ff8353fd1babe90818356ef02eae28571a2a4a7960db1f85cdbc4f88b5fb8a1f8bf44bca8c8715cdfb9ea87997c3fcd81866cd0b156d
fa8c89511d838d9adf706ec0aeac725e64427587 Fixup TODO comment in feature_dbcrash.py; remove unnecessary sleep (MarcoFalke)
Pull request description:
Fixup some stale comments:
* The `60 seconds` is outdated. It should say 120 seconds. However, just clarify that there is a timeout.
* The TODO seems to imply that a timeout (failure to restart) can happen. However, I don't think we've seen it happen. So there isn't anything to do right now. Just remove the `TODO`, but keep the advice.
Also, remove an unnecessary `time.sleep(1)`. If there is a need for it, a comment should explain why.
ACKs for top commit:
l0rinc:
ACK fa8c89511d838d9adf706ec0aeac725e64427587
Tree-SHA512: 5ee13b48fc4a5802f3fadb125d71118e01d2cb08ede9d310d6ed13acd8fb7b03185cad73c475c617054c4c4423156ea927a32d0e3a670c3cc13339b552dc8a5c
Take advantage of the new secp256k1 option to avoid visibility attributes on
API functions.
While most users of a shared libsecp always want API functions exported so that
they can actually be linked against, we always build it statically. When that
static lib is linked into a (static or shared) libbitcoinkernel, by default its
symbols end up exported there as well.
As libsecp is an implementation detail of the kernel (and any future Core lib),
its symbols should never be exported.
4c0d4f6f93f371a8ad097735945d32510a7e83bb refactor: interfaces, make 'createTransaction' less error-prone (furszy)
e2c3ec9bf4126564070f4f1097bea45753e41ead refactor: move CreatedTransactionResult to types.h (furszy)
45372175c35b73bfd33a1387b2295fc61d9eaaa9 gui: remove AmountWithFeeExceedsBalance error special case (furszy)
Pull request description:
Bundle all function's outputs inside the `util::Result` returned object.
Removals:
- The input-output 'change_pos' ref arg from `createTransaction`, which has been a source of bugs in the past.
- The 'fee' ref arg from `createTransaction`, which is currently only set when the transaction creation process succeeds.
- The no longer needed `AmountWithFeeExceedsBalance` error (more info about its re-introduction at [bitcoin#25269](https://github.com/bitcoin/bitcoin/pull/25269) and [bitcoin#34299](https://github.com/bitcoin/bitcoin/pull/34299).
Additionally, this PR moves the `CreatedTransactionResult` struct into its own file. This change is made to avoid further expanding the GUI dependencies on `wallet.h`. Structurally, the GUI should only access the model/interfaces and never the wallet directly.
ACKs for top commit:
stratospher:
ACK 4c0d4f6.
hebasto:
ACK 4c0d4f6f93f371a8ad097735945d32510a7e83bb.
Tree-SHA512: 4fc61f08ca2e66e46001defb3a2e852265713e75006c98f0c465bd48afe42e7b0d626d28d578741906fdd26e907d6919f06dc640c55c44efc3dfa766fdbf38a4
This makes TxGraph also use the fallback order to decide the order of
chunks from distinct clusters.
The order of chunks across clusters becomes:
1. Feerate (high to low)
2. Equal-feerate-chunk-prefix (small to large)
3. Max-txid (chunk with lowest maximum-txid first)
This makes the full TxGraph ordering fully deterministic as long as all
clusters in it are optimally linearized.
Add glue to make TxGraph use the fallback order provided to it, in the
fallback comparator it provides to the cluster linearization code.
The order of chunks within a cluster becomes:
1. Topology (chunks after their dependencies)
2. Feerate (high to low)
3. Weight (small to large)
4. Max-txid (chunk with lowest maximum-txid first)
The order of transactions within a chunk becomes:
1. Topology (parents before children)
2. Individual transaction feerate (high to low)
3. Weight (small to large)
4. Txid (low to high txid)
This makes optimal cluster linearization, both the order of chunks
within a chunk, and the order of transactions within those chunks,
completely deterministic.
This adds an std::function<strong_ordering(Ref&,Ref&)> argument to the
MakeTxGraph function, which can be used by the caller (e.g., mempool
code) to provide a fallback order to TxGraph.
This is just preparation; TxGraph does not yet use this fallback order
for anything.
This is a small change to the txgraph fuzz test to make it used objects
derived from TxGraph::Ref (SimTxObject) rather than TxGraph::Ref
directly. This matches how the mempool uses CTxMemPoolEntry, which
derives from TxGraph::Ref.
This is preparation for a future commit which will introduce simulated
txids to the transactions in this fuzz test, to be used as fallback
order.
This allows passing in a fallback order comparator to Linearize(), which
is used as final tiebreak when deciding the order of chunks and
transactions within a chunk, rather than a random tiebreak.
The order of transactions within a chunk becomes:
1. Topology (parents before children)
2. Individual transaction feerate (high to low)
3. Weight (small to large)
4. Fallback (low to high fallback order)
The order of chunks within a cluster becomes:
1. Topology (chunks after their dependencies)
2. Feerate (high to low)
3. Weight (small to large)
4. Max-fallback (chunk with lowest maximum-fallback-tx first)
For now, txgraph passes a naive comparator to Linearize(), which makes
the cluster order deterministic when treating the input transactions as
identified by the DepGraphIndex. However, since DepGraphIndexes are the
result of possibly-randomized operations inside txgraph, this doesn't
actually make txgraph's per-cluster ordering deterministic. That will be
changed in a later commit, by using a txid-based fallback instead.
This makes TxGraph track the equal-feerate-prefix size of all chunks in
all clusters in the main graph, and uses it to sort chunks coming from
distinct clusters.
The order of chunks across clusters becomes:
1. Feerate (high to low)
2. Equal-feerate-prefix (small to large)
3. Cluster sequence number (old to new); this will be changed later.
The equal-feerate-prefix size of a chunk C is defined as the sum
of the weights of all chunks in the same cluster as C, with the same
feerate as C, up to and including C itself, in linearization order (but
excluding such chunks that appear after C).
This is an approximation of sorting chunks from small to large across
clusters, while remaining consistent with intra-cluster linearization
order.
This changes the order of transactions within a chunk to be:
1. Topology (parents before children)
2. Individual transaction feerate (high to low)
3. Individual transaction weight (small to large)
4. Random tiebreak (will be changed in a future commit)
To do so, use a heap of topology-ready transactions within
GetLinearization(), sorted by (2), (3), and (4).
This is analogous to the order of chunks within a cluster, which is
unchanged:
1. Topology (chunks after chunks they depend on)
2. Chunk feerate (high to low)
3. Chunk weight (small to large)
4. Random tiebreak (will be changed in a future commit)
Whenever a TxGraph::Ref is destroyed, if it by then still appears inside
main-level clusters, wipe the chunk index entries for those clusters, to
prevent having lingering indexes for transactions without Ref.
This is preparation for enabling a callback being passed to MakeTxGraph
to define a fallback order on objects. Once the Ref for a transaction is
gone, it is not possible to invoke the callback anymore. To prevent the
index becoming inconsistent, we need to immediately get rid of the index
entries when the Ref disappears.
This is not a problem, because such destructions necessarily will
trigger a relinearization of the cluster (assuming there are
transactions in it left) before becoming acceptable again, and the chunk
ordering is not observable (through CompareMainOrder, or through the
BlockBuilder interface) until that point. However, the index itself
needs to remain consistent in the mean time, even if not meaningful.
This makes TxGraphImpl::Compact() invoke Cluster::Updated() on all
affected clusters, in case they have internal GraphIndex values stored
that may have become outdated with the renumbering of GraphIndex values
that Compact() caused.
No such GraphIndex values are currently stored, but this will change in
a future commit.
