6666713041 refactor: Rename fs::path::u8string() to fs::path::utf8string() (MarcoFalke)
856c88776f ArgsManager: return path by value from GetBlocksDirPath() (Vasil Dimov)
fa3d9304e8 refactor: Remove pre-C++20 fs code (MarcoFalke)
fa00098e1a Add tests for C++20 std::u8string (MarcoFalke)
fa2bac08c2 refactor: Avoid copy/move in fs.h (MarcoFalke)
faea30227b refactor: Use C++20 std::chrono::days (MarcoFalke)
Pull request description:
This:
* Removes dead code.
* Avoids unused copies in some places.
* Adds copies in other places for safety.
ACKs for top commit:
achow101:
ACK 6666713041
ryanofsky:
Code review ACK 6666713041. Just documentation change since last review.
stickies-v:
re-ACK 6666713041
Tree-SHA512: 6176e44f30b310d51632ec2d3827c3819905d0ddc6a4b57acfcb6cfa1f9735176da75ee8ed4a4abd1296cb0b83bee9374cc6f91ffac87c19b63c435eeadf3f46
6db04be102 Get rid of shutdown.cpp/shutdown.h, use SignalInterrupt directly (Ryan Ofsky)
213542b625 refactor: Add InitContext function to initialize NodeContext with global pointers (Ryan Ofsky)
feeb7b816a refactor: Remove calls to StartShutdown from KernelNotifications (Ryan Ofsky)
6824eecaf1 refactor: Remove call to StartShutdown from stop RPC (Ryan Ofsky)
1d92d89edb util: Get rid of uncaught exceptions thrown by SignalInterrupt class (Ryan Ofsky)
ba93966368 refactor: Remove call to ShutdownRequested from IndexWaitSynced (Ryan Ofsky)
42e5829d97 refactor: Remove call to ShutdownRequested from HTTPRequest (Ryan Ofsky)
73133c36aa refactor: Add NodeContext::shutdown member (Ryan Ofsky)
f4a8bd6e2f refactor: Remove call to StartShutdown from qt (Ryan Ofsky)
f0c73c1336 refactor: Remove call to ShutdownRequested from rpc/mining (Ryan Ofsky)
263b23f008 refactor: Remove call to ShutdownRequested from chainstate init (Ryan Ofsky)
Pull request description:
This change drops `shutdown.h` and `shutdown.cpp` files, replacing them with a `NodeContext::shutdown` member which is used to trigger shutdowns directly. This gets rid of an unnecessary layer of indirection, and allows getting rid of the `kernel::g_context` global.
Additionally, this PR tries to improve error handling of `SignalInterrupt` code by marking relevant methods `[[nodiscard]]` to avoid the possibility of uncaught exceptions mentioned https://github.com/bitcoin/bitcoin/pull/27861#discussion_r1255496707.
Behavior is changing In a few cases which are noted in individual commit messages. Particularly: GUI code more consistently interrupts RPCs when it is shutting down, shutdown state no longer persists between unit tests, the stop RPC now returns an RPC error if requesting shutdown fails instead of aborting, and other failed shutdown calls now log errors instead of aborting.
This PR is a net reduction in lines of code, but in some cases the explicit error handling and lack of global shutdown functions do make it more verbose. The verbosity can be seen as good thing if it discourages more code from directly triggering shutdowns, and instead encourages code to return errors or send notifications that could be translated into shutdowns. Probably a number of existing shutdown calls could just be replaced by better error handling.
ACKs for top commit:
achow101:
ACK 6db04be102
TheCharlatan:
Re-ACK 6db04be102
maflcko:
ACK 6db04be102👗
stickies-v:
re-ACK 6db04be102
Tree-SHA512: 7a34cb69085f37e813c43bdaded1a0cbf6c53bd95fdde96f0cb45346127fc934604c43bccd3328231ca2f1faf712a7418d047ceabd22ef2dca3c32ebb659e634
fa3da629a1 Remove DirIsWritable, GetUniquePath (MarcoFalke)
fad3a9793b Return LockResult::ErrorWrite in LockDirectory (MarcoFalke)
fa0afe7408 refactor: Return enum in LockDirectory (MarcoFalke)
Pull request description:
`GetUniquePath` is only used in tests and in `DirIsWritable`. The check by `DirIsWritable` is redundant with the check done in `LockDirectory`.
Fix the redundancy by removing everything, except `LockDirectory`.
ACKs for top commit:
TheCharlatan:
Re-ACK fa3da629a1
hebasto:
ACK fa3da629a1, I have reviewed the code and it looks OK.
Tree-SHA512: e95f18cd586de7582e9c08ac7ddb860bfcfcbc8963804f45c5784c5e4c0598dc59ae7e45dd4daf30a5020dbf8433f5db2ad06e46a8676371982003790043c6c9
9f265d8825 fuzz: Detect deadlocks in process_message (dergoegge)
fae1e7e012 fuzz: p2p: Detect peer deadlocks (MarcoFalke)
Pull request description:
It may be possible that a peer connection will deadlock, due to software bugs such as https://github.com/bitcoin/bitcoin/pull/18808.
Fix this by detecting them in the fuzz target.
Can be tested by introducing a bug such as:
```diff
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 1067341495..97495a13df 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -2436,3 +2436,3 @@ void PeerManagerImpl::ProcessGetData(CNode& pfrom, Peer& peer, const std::atomic
if (it != peer.m_getdata_requests.end() && !pfrom.fPauseSend) {
- const CInv &inv = *it++;
+ const CInv& inv = *it;
if (inv.IsGenBlkMsg()) {
```
Using a fuzz input such as:
```
$ base64 ./timeout-ada0fecaba2b8c46c6e970cf637d9625b01bf7e5
kNptdNbW1tbWYghvXIpwb25vPQAA////////cwAjLv8AXAB2ZXJhY2sAQW5v/62tra3Pz///////
//////////////////////9c8GZpbHRlcmxvYWQAAAEAAwAAAABVYwC2XABmaWx0ZXJhZGQAAAAX
Fxdn/////2V0F861tcqvEmAAACEAAABjYXB0dXJldmUAAH4AgAA1PNfX11x0Z2V0ZGF0YQBDACOw
AQMAAAAGIm5GERoLWcqvEmBD61u/KMNPOl4zKh/HKLK3PPGIkQ9eE/////////8AAAAAAAAAAFtb
WyjDTzpeMSofx7K3PNfX11x0Z2V0ZGF0YQBDACMwAQMAAAAGIm5GERoLWcqvEmBD61u/KMNPOl4z
Kh/Hsrc88YiRD2/Nzc3Nzc3Nzc3NTc3Nzc3Nzc3Nzc3Nzc3Nzc3Nzc3Nzc3Nzc3Nzc3Nzc3Nzc3N
zWWj1NTUudTU1NTU1P///0j+P/9cdHR4AAAAAAAAy/4AAHR4AAAAAAAAP8v+AAD/+P//////////
AX55bJl8HWnz/////wAgXGF0YVPxY2RkAAAA
```
And running the fuzz target:
```
$ FUZZ=process_messages ./src/test/fuzz/fuzz -runs=1 -timeout=18 ./timeout-ada0fecaba2b8c46c6e970cf637d9625b01bf7e5
INFO: Running with entropic power schedule (0xFF, 100).
INFO: Seed: 3436516708
INFO: Loaded 1 modules (390807 inline 8-bit counters): 390807 [0x55d0d6221e80, 0x55d0d6281517),
INFO: Loaded 1 PC tables (390807 PCs): 390807 [0x55d0d6281518,0x55d0d6877e88),
./src/test/fuzz/fuzz: Running 1 inputs 1 time(s) each.
Running: ./timeout-ada0fecaba2b8c46c6e970cf637d9625b01bf7e5
ALARM: working on the last Unit for 19 seconds
and the timeout value is 18 (use -timeout=N to change)
==375014== ERROR: libFuzzer: timeout after 19 seconds
```
ACKs for top commit:
naumenkogs:
ACK 9f265d8825
dergoegge:
ACK 9f265d8825
brunoerg:
ACK 9f265d8825
Tree-SHA512: da83ff90962bb679aae00e8e9dba639c180b7aaba544e0c4d0978d36e28a9ff1cd7a2e13009d8ab407ef57767656aca1ebc767a7d2f1bc880284f8f57c197a50
15f5a0d0c8 fuzz: Improve fuzzing stability for txorphan harness (dergoegge)
Pull request description:
The `txorphan` harness has low stability as eviction of orphan txs is entirely random at the moment.
Fix this by passing the rng to `LimitOrphans`, which can be deterministic in tests.
Also see #29018.
ACKs for top commit:
maflcko:
lgtm ACK 15f5a0d0c8
brunoerg:
utACK 15f5a0d0c8
Tree-SHA512: 854ec34b3a0f16f26db6dc419096c6e7a380e8400119534aa278d6b1d54c253b572aa2fad13c383c796c431d8ff4263956e6f60326e99f8bf6abd16d9a280e97
fa6e50d6c7 fuzz: Use C++20 starts_with in rpc.cpp (MarcoFalke)
faa48388bc Revert "tracepoints: Disables `-Wgnu-zero-variadic-macro-arguments` to compile without warnings" (MarcoFalke)
fae3b77a87 refactor: Drop unused _Pragma to ignore -Wgnu-zero-variadic-macro-arguments (MarcoFalke)
fa02fc0a86 refactor: modernize-use-default-member-init for bit-fields (C++20) (MarcoFalke)
fa67f096bd build: Require C++20 compiler (MarcoFalke)
Pull request description:
C++20 allows to write safer code, because it allows to enforce more stuff at compile time (`constinit`, `conteval`, `constexpr`, `std::span`, ...).
Also, it allows to write less verbose and easier to understand code (C++ 20 Concepts).
See https://github.com/bitcoin/bitcoin/issues/23363 and https://en.cppreference.com/w/cpp/compiler_support#cpp20
With g++-10 (https://github.com/bitcoin/bitcoin/pull/28348) and clang-13 (https://github.com/bitcoin/bitcoin/pull/28210), there is broad support for almost all features of C++20.
It should be fine to require a C++20 compiler for Bitcoin Core 27.0 in 2024 (next year), not the soon upcoming 26.0 next month.
This pull request includes three small cleanups to make use of C++20 features. If any issues are detected before or after merge, this should be easy to revert. If no issues arise, it should be fine to make use of more involved C++20 features later on.
ACKs for top commit:
fanquake:
ACK fa6e50d6c7
Tree-SHA512: 244d79bfb0b750a4bdd713f40573b9ca33816fb84b6c84a58f027b9d7d4bb0cc4f18642959e4cf3d094808a69e5b8a327ca8521d7c0c08af27dacb5da3e78e71
fa63f16018 test: Add uint256 string parse tests (MarcoFalke)
facf629ce8 refactor: Remove unused and fragile string interface from arith_uint256 (MarcoFalke)
Pull request description:
The string interface (`base_uint(const std::string&)`, as well as `base_uint::SetHex`) is problematic for many reasons:
* It is unused (except in test-only code).
* It is redundant with the `uint256` string interface: `std::string -> uint256 -> UintToArith256`.
* It is brittle, because it inherits the brittle `uint256` string interface, which is brittle due to the use of `c_str()` (embedded null will be treated as end-of string), etc ...
Instead of fixing the interface, remove it since it is unused and redundant with `UintToArith256`.
ACKs for top commit:
ajtowns:
ACK fa63f16018
TheCharlatan:
ACK fa63f16018
Tree-SHA512: a95d5b938ffd0473361336bbf6be093d01265a626c50be1345ce2c5e582c0f3f73eb11af5fd1884019f59d7ba27e670ecffdb41d2c624ffb9aa63bd52b780e62
All functions assume that the pointer is never null, so pass by
reference, to avoid accidental segfaults at runtime, or at least make
them more obvious.
Also, remove unused c-style casts in touched lines.
Also, add CHECK_NONFATAL checks, to turn segfault crashes into an
recoverable runtime error with debug information.
fad1903b8a fuzz: Avoid timeout in bitdeque (MarcoFalke)
Pull request description:
Avoid timeouts such as https://github.com/bitcoin/bitcoin/issues/28812#issuecomment-1842914664
This is done by:
* Limiting the maximum number of iterations if the maximum size of the container is "large" (see the magic numbers in the code).
* Check the equality only once. This should be fine, because if a crash were to happen in the equality check, but the crash doesn't happen if further iterations were run, the fuzz engine should eventually find the crash by truncating the fuzz input.
ACKs for top commit:
sipa:
utACK fad1903b8a
dergoegge:
utACK fad1903b8a
brunoerg:
crACK fad1903b8a
Tree-SHA512: d3d83acb3e736b8fcaf5d17ce225ac82a9f9a2efea048512d2fed594ba6c76c25bae72eb0fab3276d4db37baec0752e5367cecfb18161301b921fed09693045e
3ea54e5db7 net: Add continuous ASMap health check logging (Fabian Jahr)
28d7e55dff test: Add tests for unfiltered GetAddr usage (Fabian Jahr)
b8843d37ae fuzz: Let fuzzers use filter options in GetAddr/GetAddresses (Fabian Jahr)
e16f420547 net: Optionally include terrible addresses in GetAddr results (Fabian Jahr)
Pull request description:
There are certain statistics we can collect by running all our known clearnet addresses against the ASMap file. This could show issues with a maliciously manipulated file or with an old file that has decayed with time.
This is just a proof of concept for now. My idea currently is to run the analysis once per day and print the results to logs if an ASMap file is used.
ACKs for top commit:
achow101:
ACK 3ea54e5db7
mzumsande:
ACK 3ea54e5db7
brunoerg:
crACK 3ea54e5db7
Tree-SHA512: 777acbfac43cc43ce4a0a3612434e4ddbc65f59ae8ffc9e24f21de09011bccb297f0599cbaa82bcf40ef68e5af582c4e98556379db7ceff7d9f97574a1cf8e09
55e3dc3e03 test: Fix test by checking the actual exception instance (Hennadii Stepanov)
Pull request description:
The `system_tests/run_command` test is broken because it passes even with the diff as follows:
```diff
--- a/src/test/system_tests.cpp
+++ b/src/test/system_tests.cpp
@@ -90,7 +90,7 @@ BOOST_AUTO_TEST_CASE(run_command)
});
}
{
- BOOST_REQUIRE_THROW(RunCommandParseJSON("echo \"{\""), std::runtime_error); // Unable to parse JSON
+ BOOST_REQUIRE_THROW(RunCommandParseJSON("invalid_command \"{\""), std::runtime_error); // Unable to parse JSON
}
// Test std::in, except for Windows
#ifndef WIN32
```
The reason of such fragility is that the [`BOOST_REQUIRE_THROW`](https://www.boost.org/doc/libs/1_83_0/libs/test/doc/html/boost_test/utf_reference/testing_tool_ref/assertion_boost_level_throw.html) macro passes even if the command raises an exception in the underlying subprocess implementation, which might have a type derived from `std::runtime_error`.
ACKs for top commit:
maflcko:
lgtm ACK 55e3dc3e03
achow101:
ACK 55e3dc3e03
furszy:
Non-Windows code ACK 55e3dc3e
pablomartin4btc:
ACK 55e3dc3e03
Tree-SHA512: 32f49421bdcc94744c81e82dc10cfa02e3f8ed111974edf1c2a47bdaeb56d7baec1bede67301cc89464fba613029ecb131dedc6bc5948777ab52f0f12df8bfe9
This change is mostly a refectoring that removes some code and gets rid of an
unnecessary layer of indirection after #27861
But it is not a pure refactoring since StartShutdown, AbortShutdown, and
WaitForShutdown functions used to abort on failure, and the replacement code
logs or returns errors instead.
Use SignalInterrupt object instead. There is a slight change in behavior here
because the previous StartShutdown code used to abort on failure and the
new code logs errors instead.
Pass HTTP server an interrupt object instead of having it depend on shutdown.h
and global shutdown state.
There is no change in behavior in this commit.
Add NodeContext::shutdown variable and start using it to replace the
kernel::Context::interrupt variable. The latter can't easily be removed right
away but will be removed later in this PR.
Moving the interrupt object from the kernel context to the node context
increases flexibility of the kernel API so it is possible to use multiple
interrupt objects, or avoid creating one if one is not needed. It will also
allow getting rid of the kernel::g_context global later in this PR, replacing
it with a private SignalInterrupt instance in init.cpp
There is no change in behavior in this commit outside of unit tests. In unit
tests there should be no visible change either, but internally now each test
has its own interrupt variable so the variable will be automatically reset
between tests.
The BOOST_REQUIRE_THROW passes even if the command raises an exception
in the underlying subprocess implementation, which might have a type
derived from std::runtime_error.
91504cbe0d rpc: `SyncWithValidationInterfaceQueue` on fee estimation RPC's (ismaelsadeeq)
714523918b tx fees, policy: CBlockPolicyEstimator update from `CValidationInterface` notifications (ismaelsadeeq)
dff5ad3b99 CValidationInterface: modify the parameter of `TransactionAddedToMempool` (ismaelsadeeq)
91532bd382 tx fees, policy: update `CBlockPolicyEstimator::processBlock` parameter (ismaelsadeeq)
bfcd401368 CValidationInterface, mempool: add new callback to `CValidationInterface` (ismaelsadeeq)
0889e07987 tx fees, policy: cast with static_cast instead of C-Style cast (ismaelsadeeq)
a0e3eb7549 tx fees, policy: bugfix: move `removeTx` into reason != `BLOCK` condition (ismaelsadeeq)
Pull request description:
This is an attempt to #11775
This Pr will enable fee estimator to listen to ValidationInterface notifications to process new transactions added and removed from the mempool.
This PR includes the following changes:
- Added a new callback to the Validation Interface `MempoolTransactionsRemovedForConnectedBlock`, which notifies listeners about the transactions that have been removed due to a new block being connected, along with the height at which the transactions were removed.
- Modified the `TransactionAddedToMempool` callback parameter to include additional information about the transaction needed for fee estimation.
- Updated `CBlockPolicyEstimator` to process transactions using` CTransactionRef` instead of `CTxMempoolEntry.`
- Implemented the `CValidationInterface` interface in `CBlockPolicyEstimater` and overridden the `TransactionAddedToMempool`, `TransactionRemovedFromMempool`, and `MempoolTransactionsRemovedForConnectedBlock` methods to receive updates from their notifications.
Prior to this PR, the fee estimator updates from the mempool, i.e whenever a new block is connected all transactions in the block that are in our mempool are going to be removed using the `removeForBlock` function in `txmempool.cpp`.
This removal triggered updates to the fee estimator. As a result, the fee estimator would block mempool's `cs` until it finished updating every time a new block was connected.
Instead of being blocked only on mempool tx removal, we were blocking on both tx removal and fee estimator updating.
If we want to further improve fee estimation, or add heavy-calulation steps to it, it is currently not viable as we would be slowing down block relay in the process
This PR is smaller in terms of the changes made compared to #11775, as it focuses solely on enabling fee estimator updates from the validationInterface/cscheduler thread notifications.
I have not split the validation interface because, as I understand it, the rationale behind the split in #11775 was to have `MempoolInterface` signals come from the mempool and `CValidationInterface` events come from validation. I believe this separation can be achieved in a separate refactoring PR when the need arises.
Also left out some commits from #11775
- Some refactoring which are no longer needed.
- Handle reorgs much better in fee estimator.
- Track witness hash malleation in fee estimator
I believe they are a separate change that can come in a follow-up after this.
ACKs for top commit:
achow101:
ACK 91504cbe0d
TheCharlatan:
Re-ACK 91504cbe0d
willcl-ark:
ACK 91504cbe0d
Tree-SHA512: 846dfb9da57a8a42458827b8975722d153907fe6302ad65748d74f311e1925557ad951c3d95fe71fb90ddcc8a3710c45abb343ab86b88780871cb9c38c72c7b1
fa98a097a3 Rename version.h to node/protocol_version.h (MarcoFalke)
fa4fbd5816 Remove unused version.h include (MarcoFalke)
fa0ae22ff2 Remove unused SER_NETWORK, SER_DISK (MarcoFalke)
fae00fe9c2 Remove unused CDataStream (MarcoFalke)
fa7eb4f5c3 fuzz: Drop unused version from fuzz input format (MarcoFalke)
Pull request description:
Seems odd to have code that is completely dead.
Fix this by removing all of it.
ACKs for top commit:
sipa:
utACK fa98a097a3
ajtowns:
ACK fa98a097a3
ryanofsky:
Seems odd to not code review ACK fa98a097a3 (looks good)
Tree-SHA512: 9f1b9d9f92bda0512610bda6653e892756f637860362a9abfa439faab62de233cbad94b7df78ebacc160d9667aadfed4d9df08c0edefa618c040a049050fb913
e67634ef19 fuzz: BIP324: damage ciphertext/aad in full byte range (Sebastian Falbesoner)
Pull request description:
This PR is a tiny improvement for the `bip324_cipher_roundtrip` fuzz target: currently the damaging of input data for decryption (either ciphertext or aad) only ever happens in the lower nibble within the byte at the damage position, as the bit position for the `damage_val` byte was calculated with `damage_bit & 3` (corresponding to `% 4`) rather than `damage_bit & 7` (corresponding to the expected `% 8`).
Noticed while reviewing #28263 which uses similar constructs.
ACKs for top commit:
stratospher:
ACK e67634ef.
dergoegge:
utACK e67634ef19
Tree-SHA512: 1bab4df28708e079874feee939beef45eff235215375c339decc696f4c9aef04e4b417322b045491c8aec6e88ec8ec2db564e27ef1b0be352b6ff4ed38bad49a
Also, add missing includes to scriptpubkeyman.
Also, export dependecies of the BasicTestingSetup from setup_common.h,
to avoid having to include them when setup_common.h is already included.
fa02c08c93 refactor: Use Txid in CMerkleBlock (MarcoFalke)
Pull request description:
This should also fix a gcc-13 compiler warning, see https://github.com/bitcoin/bitcoin/pull/28922#discussion_r1407856376
```
rpc/txoutproof.cpp: In lambda function:
rpc/txoutproof.cpp:72:33: error: possibly dangling reference to a temporary [-Werror=dangling-reference]
72 | const Coin& coin = AccessByTxid(active_chainstate.CoinsTip(), Txid::FromUint256(tx));
| ^~~~
rpc/txoutproof.cpp:72:52: note: the temporary was destroyed at the end of the full expression ‘AccessByTxid((*(const CCoinsViewCache*)(&(& active_chainstate)->Chainstate::CoinsTip())), transaction_identifier<false>::FromUint256((* & tx)))’
72 | const Coin& coin = AccessByTxid(active_chainstate.CoinsTip(), Txid::FromUint256(tx));
| ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors
ACKs for top commit:
TheCharlatan:
Re-ACK fa02c08c93
dergoegge:
reACK fa02c08c93
Tree-SHA512: 2e6837b9d0c90bd6e9d766330e7086d68c6ec80bb27fe2cfc4702b251b00d91a79f8bfbc76d998cbcd90bee5317402cf617f61099eee96d94e7ac8f37ba7a642
705e3f1de0 refactor: Make CTxMemPoolEntry only explicitly copyable (TheCharlatan)
Pull request description:
This has the goal of prohibiting users from accidentally creating runtime failures, e.g. by interacting with iterator_to with a copied entry. This was brought up here: https://github.com/bitcoin/bitcoin/pull/28886#issuecomment-1814794954.
CTxMemPoolEntry is already implicitly not move-constructable. So be explicit about this and use a std::list to collect the values in the policy_estimator fuzz test instead of a std::vector.
ACKs for top commit:
maflcko:
ACK 705e3f1de0🌯
achow101:
ACK 705e3f1de0
ajtowns:
ACK 705e3f1de0
ismaelsadeeq:
ACK 705e3f1de0
Tree-SHA512: 62056905c679c919d00f9ae065ed66ac986e7e7062015aea542843d8deecda57104d7a68d002f7b20afa3164f8e9215d2d2d002c167224129540e3b1bd0712cc
fae76a1f2a scripted-diff: Use DataStream in most places (MarcoFalke)
fac39b56b7 refactor: SpanReader without nVersion (MarcoFalke)
Pull request description:
The serialize version is unused, so remove it. This also allows to remove `GCS_SER_VERSION` and allows a scripted-diff to remove most of `CDataStream`.
ACKs for top commit:
ajtowns:
ACK fae76a1f2a
ryanofsky:
Code review ACK fae76a1f2a
Tree-SHA512: 3b487dba8ea380f1eacff9fdfb9197f025dbc30906813d3f4c3e6f1e9e4d9f2a169c6f163f51d135e18af538be78e2d2b13d694073ad25c5762980ae971a4c83
Allow any C++ object that has Serialize and Unserialize methods and can be
serialized to a bitcoin CDataStream to be converted to a capnproto Data field
and passed as arguments or return values to capnproto methods using the Data
type.
Extend IPC unit test to cover this and verify the serialization happens
correctly.
