We previously identified if we relay addresses to the connection by checking
for the existence of the m_addr_known data structure. With this commit, we
answer this question based on the connection type.
IsAddrRelayPeer() checked for the existence of the m_addr_known
46fcac1e4b tests: Add fuzzing harness for ec_seckey_import_der(...) and ec_seckey_export_der(...) (practicalswift)
b667a90389 tests: Add fuzzing harness for SigHasLowR(...) and ecdsa_signature_parse_der_lax(...) (practicalswift)
Pull request description:
Add fuzzing harness for `SigHasLowR(...)` and `ecdsa_signature_parse_der_lax(...)`.
See [`doc/fuzzing.md`](https://github.com/bitcoin/bitcoin/blob/master/doc/fuzzing.md) for information on how to fuzz Bitcoin Core. Don't forget to contribute any coverage increasing inputs you find to the [Bitcoin Core fuzzing corpus repo](https://github.com/bitcoin-core/qa-assets).
Happy fuzzing :)
ACKs for top commit:
Crypt-iQ:
ACK 46fcac1e4b
Tree-SHA512: 11a4856a1efd9a04030a8c8aee2413fd5be1ea248147e649a48a55bacdf732bb48a19ee1ce2761d47d4dd61c9598aec53061b961b319ad824d539dda11a8ccf4
fa0572d0f3 Pass mempool reference to chainstate constructor (MarcoFalke)
Pull request description:
Next step toward #19556
Instead of relying on the mempool global, each chainstate is given a reference to a mempool to keep up to date with the tip (block connections, disconnections, reorgs, ...)
ACKs for top commit:
promag:
Code review ACK fa0572d0f3.
darosior:
ACK fa0572d0f3
hebasto:
ACK fa0572d0f3, reviewed and tested on Linux Mint 20 (x86_64).
Tree-SHA512: 12184d33ae5797438d03efd012a07ba3e4ffa0d817c7a0877743f3d7a7656fe279280c751554fc035ccd0058166153b6c6c308a98b2d6b13998922617ad95c4c
8e35bf5906 scripted-diff: rename misbehavior members (John Newbery)
1f96d2e673 [net processing] Move misbehavior tracking state to Peer (John Newbery)
7cd4159ac8 [net processing] Add Peer (John Newbery)
aba03359a6 [net processing] Remove CNodeState.name (John Newbery)
Pull request description:
We currently have two structures for per-peer data:
- `CNode` in net, which should just contain connection layer data (eg socket, send/recv buffers, etc), but currently also contains some application layer data (eg tx/block inventory).
- `CNodeState` in net processing, which contains p2p application layer data, but requires cs_main to be locked for access.
This PR adds a third struct `Peer`, which is for p2p application layer data, and doesn't require cs_main. Eventually all application layer data from `CNode` should be moved to `Peer`, and any data that doesn't strictly require cs_main should be moved from `CNodeState` to `Peer` (probably all of `CNodeState` eventually).
`Peer` objects are stored as shared pointers in a net processing global map `g_peer_map`, which is protected by `g_peer_mutex`. To use a `Peer` object, `g_peer_mutex` is locked, a copy of the shared pointer is taken, and the lock is released. Individual members of `Peer` are protected by different mutexes that guard related data. The lifetime of the `Peer` object is managed by the shared_ptr refcount.
This PR adds the `Peer` object and moves the misbehaving data from `CNodeState` to `Peer`. This allows us to immediately remove 15 `LOCK(cs_main)` instances.
For more motivation see #19398
ACKs for top commit:
laanwj:
Code review ACK 8e35bf5906
troygiorshev:
reACK 8e35bf5906 via `git range-diff master 9510938 8e35bf5`
theuni:
ACK 8e35bf5906.
jonatack:
ACK 8e35bf5906 keeping in mind Cory's comment (https://github.com/bitcoin/bitcoin/pull/19607#discussion_r470173964) for the follow-up
Tree-SHA512: ad84a92b78fb34c9f43813ca3dfbc7282c887d55300ea2ce0994d134da3e0c7dbc44d54380e00b13bb75a57c28857ac3236bea9135467075d78026767a19e4b1
fa9d5902f7 scripted-diff: gArgs -> args (MarcoFalke)
fa33bc2dab init: Capture copy of blocknotify setting for BlockNotifyCallback (MarcoFalke)
fa40017706 init: Pass reference to ArgsManager around instead of relying on global (MarcoFalke)
Pull request description:
The gArgs global has several issues:
* gArgs is used by each process (bitcoind, bitcoin-qt, bitcoin-wallet, bitcoin-cli, bitcoin-tx, ...), but it is hard to determine which arguments are actually used by each process. For example arguments that have never been registered, but are still used, will always return the fallback value.
* Tests may run several sub-tests, which need different settings. So globals will have to be overwritten, but that is fragile on its own: e.g. https://github.com/bitcoin/bitcoin/pull/19704#issuecomment-678259092 or #19511
The goal is to remove gArgs, but as a first step in that direction this pull will change gArgs in init to use a passed-in reference instead.
ACKs for top commit:
ryanofsky:
Code review ACK fa9d5902f7. Looks good. Nice day to remove some globals, and add some lambdas 👍
fanquake:
ACK fa9d5902f7 - I'm not as familiar with the settings & argument handling code, but this make sense, and is a step in the right direction towards a reduction in the usage of globals. Not a huge fan of the clang-formatting in the scripted diff.
jonasschnelli:
Concept ACK fa9d5902f7
Tree-SHA512: ed00db5f826566c7e3b4d0b3d2ee0fc1a49a6e748e04e5c93bdd694ac7da5598749e73937047d5fce86150d764a067d2ca344ba4ae3eb2704cc5c4fa0d20940f
fad84b7e14 test: Activate segwit in TestChain100Setup (MarcoFalke)
fa11ff2980 test: Pass empty tx pool to block assembler (MarcoFalke)
fa96574b0d test: Move doxygen comment to header (MarcoFalke)
Pull request description:
This fixes not only a TODO in the code, but also prevents a never ending source of uninitialized reads. E.g.
* #18376
* https://github.com/bitcoin/bitcoin/pull/19704#issuecomment-678259092
* ...
ACKs for top commit:
jnewbery:
utACK fad84b7e14
Tree-SHA512: 64cf16a59656d49e022b603f3b06441ceae35a33a4253b4382bc8a89a56e08ad5412c8fa734d0fc7b58586f40ea6d57b348a3b4838bc6890a41ae2ec3902e378
102867c587 net: change CNetAddr::ip to have flexible size (Vasil Dimov)
1ea57ad674 net: don't accept non-left-contiguous netmasks (Vasil Dimov)
Pull request description:
(chopped off from #19031 to ease review)
Before this change `CNetAddr::ip` was a fixed-size array of 16 bytes,
not being able to store larger addresses (e.g. TORv3) and encoded
smaller ones as 16-byte IPv6 addresses.
Change its type to `prevector`, so that it can hold larger addresses and
do not disguise non-IPv6 addresses as IPv6. So the IPv4 address
`1.2.3.4` is now encoded as `01020304` instead of
`00000000000000000000FFFF01020304`.
Rename `CNetAddr::ip` to `CNetAddr::m_addr` because it is not an "IP" or
"IP address" (TOR addresses are not IP addresses).
In order to preserve backward compatibility with serialization (where
e.g. `1.2.3.4` is serialized as `00000000000000000000FFFF01020304`)
introduce `CNetAddr` dedicated legacy serialize/unserialize methods.
Adjust `CSubNet` accordingly. Still use `CSubNet::netmask[]` of fixed 16
bytes, but use the first 4 for IPv4 (not the last 4). Do not accept
invalid netmasks that have 0-bits followed by 1-bits and only allow
subnetting for IPv4 and IPv6.
Co-authored-by: Carl Dong <contact@carldong.me>
ACKs for top commit:
sipa:
utACK 102867c587
MarcoFalke:
Concept ACK 102867c587
ryanofsky:
Code review ACK 102867c587. Just many suggested updates since last review. Thanks for following up on everything!
jonatack:
re-ACK 102867c587 diff review, code review, build/tests/running bitcoind with ipv4/ipv6/onion peers
kallewoof:
ACK 102867c587
Tree-SHA512: d60bf716cecf8d3e8146d2f90f897ebe956befb16f711a24cfe680024c5afc758fb9e4a0a22066b42f7630d52cf916318bedbcbc069ae07092d5250a11e8f762
Before this change `CNetAddr::ip` was a fixed-size array of 16 bytes,
not being able to store larger addresses (e.g. TORv3) and encoded
smaller ones as 16-byte IPv6 addresses.
Change its type to `prevector`, so that it can hold larger addresses and
do not disguise non-IPv6 addresses as IPv6. So the IPv4 address
`1.2.3.4` is now encoded as `01020304` instead of
`00000000000000000000FFFF01020304`.
Rename `CNetAddr::ip` to `CNetAddr::m_addr` because it is not an "IP" or
"IP address" (TOR addresses are not IP addresses).
In order to preserve backward compatibility with serialization (where
e.g. `1.2.3.4` is serialized as `00000000000000000000FFFF01020304`)
introduce `CNetAddr` dedicated legacy serialize/unserialize methods.
Adjust `CSubNet` accordingly. Still use `CSubNet::netmask[]` of fixed 16
bytes, but use the first 4 for IPv4 (not the last 4). Only allow
subnetting for IPv4 and IPv6.
Co-authored-by: Carl Dong <contact@carldong.me>
A netmask that contains 1-bits after 0-bits (the 1-bits are not
contiguous on the left side) is invalid [1] [2].
The code before this PR used to parse and accept such
non-left-contiguous netmasks. However, a coming change that will alter
`CNetAddr::ip` to have flexible size would make juggling with such
netmasks more difficult, thus drop support for those.
[1] https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#Subnet_masks
[2] https://tools.ietf.org/html/rfc4632#section-5.1
daed542a12 [net_processing] Move ProcessMessage to PeerLogicValidation (John Newbery)
c556770b5e [net_processing] Change PeerLogicValidation to hold a connman reference (John Newbery)
Pull request description:
Rather than ProcessMessage() being a static function in net_processing.cpp, make it a private member function of PeerLogicValidation. This is the start of moving static functions and global variables into PeerLogicValidation to make it better encapsulated.
ACKs for top commit:
jonatack:
ACK daed542a12 code review and debug tested
promag:
Code review ACK daed542a12.
MarcoFalke:
re-ACK daed542a12, only change is removing second commit 🎴
theStack:
Code Review ACK daed542a12
Tree-SHA512: ddebf410d114d9ad5a9e536950018ff333a347c035d74fcc101fb4a3f20a281782c7eac2b7d1bd1c8f6bc7e59f5b5630fb52c2e1b4c32df454fa584673bd021e
71e0f07e9c util: remove unused c-string variant of atoi64() (Sebastian Falbesoner)
Pull request description:
This is another micro-PR "removing old cruft with potentially sharp edges" (quote by practicalswift, see #19739). Gets rid of the c-string variant of the function `atoi64()`, which is only used in fuzzers and on one place with `wallet/wallet.h` (where it is originally a `std::string` anyways and uses `.c_str()` -- this method call can simply be removed.)
ACKs for top commit:
practicalswift:
ACK 71e0f07e9c -- diff looks correct
laanwj:
ACK 71e0f07e9c
Tree-SHA512: 4d1d28e2f5274fdbe0652e7a0f83dd416f4d19c1e1a49979927960a3ad40b0990eeaa4374656bf2c6998a965a14d62c1bc78303b7d583d3307c17828030a8e3b
356988e200 util: make EncodeBase58Check consume Spans (Sebastian Falbesoner)
f0fce0675d util: make EncodeBase58 consume Spans (Sebastian Falbesoner)
Pull request description:
This PR improves the interfaces for the functions `EncodeBase58{Check}` by using Spans, in a similar fashion to e.g. PRs #19660, #19687. Note that on the master branch there are currently two versions of `EncodeBase58`: one that takes two pointers (marking begin and end) and another one that takes a `std::vector<unsigned char>` const-ref. The PR branch only leaves one generic Span-interface, both simplifying the interface and allowing more generic containers to be passed. The same is done for `EncodeBase58Check`, where only one interface existed but it's more generic now (e.g. a std::array can be directly passed, as done in the benchmarks).
ACKs for top commit:
laanwj:
Code review ACK 356988e200
Tree-SHA512: 47cfccdd7f3a2d4694bb8785e6e5fd756daee04ce1652ee59a7822e7e833b4a441ae9362b9bd67ea020d2b5b7d927629c9addb6abaa9881d8564fd3b1257f512
7966aa424a Add variables for repeated scripts (MeshCollider)
fec8336ad9 Remove GetScriptForWitness function (MeshCollider)
b887060d06 Replace usage of GetScriptForWitness with GetScriptForDestination (MeshCollider)
Pull request description:
As per this TODO in the code:
> TODO: replace calls to GetScriptForWitness with GetScriptForDestination using the various witness-specific CTxDestination subtypes.
The commit "Add additional check for P2SH before adding extra wrapper" also adds an additional check that the scriptPubKey is a P2SH before auto-wrapping the witness script. We shouldn't wrap the witness script if not. Note: #16251 is even better than this check, please review that.
ACKs for top commit:
instagibbs:
ACK 7966aa424a
jonatack:
Code review re-ACK 7966aa4 per `git range-diff b4d0366 ed266f7 7966aa4`
achow101:
re-ACK 7966aa424a only changes since last is rebase.
Tree-SHA512: 3449e0e83bd842acc7c94544a85367da97ac20d859eefc1a618caef0c98204398c266fe8fb9600b78326df5175402e1ae4a132eb766e2c4485e7cda6a2a95c43
35cd2da623 test: Fix 'make cov' with clang (Hennadii Stepanov)
Pull request description:
This is a follow up of #19688.
With this PR it is possible to do the following:
```
$ ./autogen.sh
$ ./configure --enable-lcov CC=clang CXX=clang++
$ make
$ make cov
```
Currently, on master (8a85377cd0), `make cov` fails to `Processing src/test/test_bitcoin-util_tests.gcda`.
ACKs for top commit:
vasild:
ACK 35cd2da
Crypt-iQ:
ACK 35cd2da
Tree-SHA512: aaf56118e2644064e9738a8279889c617db5805c5c804c904469b24c496bd609f9c5fc2aebcf1a422f8a5ed2eb38bd6e76b484680310b55c36d922b73a4c33cf
dca28634d7 test: ensure OP_1NEGATE satisfies BIP62 minimal push rule (Jon Atack)
e629d07199 Do not turn OP_1NEGATE in scriptSig into 0x0181 in signing code (Pieter Wuille)
Pull request description:
A rebase of #13084 which additionally modifies the test code (unaddressed in the original, assuming sipa is too busy to deal with this at the moment).
Relatively simple bugfix so it'd be good to have merged soon.
Turning OP_1NEGATE into 0x0181 results in a larger-than-necessary data push instead of just actually using the OP_1NEGATE opcode (0x4f). This fails the minimal push rule of BIP 62 and makes the result non-standard.
ACKs for top commit:
fjahr:
Code review ACK dca28634d7
luke-jr:
ACK dca28634d7
jonatack:
ACK dca28634d7
Tree-SHA512: 706d9a2ef20c809dea923e477a873e2fd60db8d0ae64289e510b766a38005c1f31ab0b5883f16b9c7863ff0d3f705e8e413f6121320028ac196b79c3184a4113
Hold a reference to connman rather than a pointer because:
- PeerLogicValidation can't run without a connman
- The pointer never gets reseated
The alternative is to always assert that the pointer is non-null before
dereferencing.
Change the name from connman to m_connman at the same time to conform
with current style guidelines.
37a480e0cd [net] Add addpeeraddress RPC method (John Newbery)
ae8051bbd8 [test] Test that getnodeaddresses() can return all known addresses (John Newbery)
f26502e9fc [addrman] Specify max addresses and pct when calling GetAddresses() (John Newbery)
Pull request description:
Currently addrman only allows a maximum of 1000 records or 23% of all records to be returned in a call to `GetAddr()`. Relax this limit and have the client specify the max records they want. For p2p, behaviour is unchanged (but the rate limiting is set inside net_processing, where it belongs). For RPC, `getnodeaddresses` can now return the complete addrman, which is helpful for testing and monitoring.
Also add a test-only RPC `addpeeraddress`, which adds an IP address:port to addrman. This is helpful for testing (eg #18991).
ACKs for top commit:
naumenkogs:
utACK 37a480e0cd
laanwj:
Code review and lightly manually tested ACK 37a480e0cd
Tree-SHA512: f86dcd410aaebaf6e9ca18ce6f23556e5e4649c1325577213d873aa09967298e65ab2dc19a72670641ae92211a923afda1fe124a82e9d2c1cad73d478ef27fdc
Misbehavior tracking state is now contained in Peer instead of
CNode. It is no longer guarded by cs_main, but instead by a
dedicated m_misbehavior_mutex lock.
This allows us to remove 14 cs_main locks from net_processing.
CAddrMan.GetAddr() would previously limit the number and percentage of
addresses returned (to ADDRMAN_GETADDR_MAX (1000) and
ADDRMAN_GETADDR_MAX_PCT (23) respectively). Instead, make it the callers
responsibility to specify the maximum addresses and percentage they want
returned.
For net_processing, the maximums are MAX_ADDR_TO_SEND (1000) and
MAX_PCT_ADDR_TO_SEND (23). For rpc/net, the maximum is specified by the
client.
01e283068b [net] Remove unnecessary default args on CNode constructor (Amiti Uttarwar)
bc5d65b3ca [refactor] Remove IsOutboundDisconnectionCandidate (Amiti Uttarwar)
2f2e13b6c2 [net/refactor] Simplify multiple-connection checks (Amiti Uttarwar)
7f7b83deb2 [net/refactor] Rework ThreadOpenConnections logic (Amiti Uttarwar)
35839e963b [net] Fix bug where AddrFetch connections would be counted as outbound full relay (Amiti Uttarwar)
4972c21b67 [net/refactor] Clarify logic for selecting connections in ThreadOpenConnections (Amiti Uttarwar)
60156f5fc4 [net/refactor] Remove fInbound flag from CNode (Amiti Uttarwar)
7b322df629 [net/refactor] Remove m_addr_fetch member var from CNode (Amiti Uttarwar)
14923422b0 [net/refactor] Remove fFeeler flag from CNode (Amiti Uttarwar)
49efac5cae [net/refactor] Remove m_manual_connection flag from CNode (Amiti Uttarwar)
d3698b5ee3 [net/refactor] Add connection type as a member var to CNode (Amiti Uttarwar)
46578c03e9 [doc] Describe different connection types (Amiti Uttarwar)
442abae2ba [net/refactor] Add AddrFetch connections to ConnectionType enum (Amiti Uttarwar)
af59feb052 [net/refactor] Extract m_addr_known logic from initializer list (Amiti Uttarwar)
e1bc29812d [net/refactor] Add block relay only connections to ConnectionType enum (Amiti Uttarwar)
0e52a659a2 [net/refactor] Add feeler connections to ConnectionType enum (Amiti Uttarwar)
1521c47438 [net/refactor] Add manual connections to ConnectionType enum (Amiti Uttarwar)
26304b4100 [net/refactor] Introduce an enum to distinguish type of connection (Amiti Uttarwar)
3f1b7140e9 scripted-diff: Rename OneShot to AddrFetch (Amiti Uttarwar)
Pull request description:
**This is part 1 of #19315, which enables the ability to test `outbound` and `block-relay-only` connections from the functional tests.** Please see that PR for more information of overall functionality.
**This PR simplifies how we manage different connection types.** It introduces an enum with the various types of connections so we can explicitly define the connection type. The existing system relies on a series of independent flags, then has asserts scattered around to ensure that conflicting flags are not enabled at the same time. I find this approach to be both brittle and confusing. While making these changes, I found a small bug due to the silent assumptions.
This PR also proposes a rename from `OneShot` to `AddrFetch`. I find the name `OneShot` to be very confusing, especially when we also have `onetry` manual connections. Everyone I've talked to offline has agreed that the name is confusing, so I propose a potential alternative. I think this is a good opportunity for a rename since I'm creating an enum to explicitly define the connection types.
(some context for the unfamiliar: `oneshot` or `addrfetch` connections are short-lived connections created on startup. They connect to the seed peers, send a `getaddr` to solicit addresses, then close the connection.)
Overview of this PR:
* rename `oneshot` to `addrfetch`
* introduce `ConnectionType` enum
* one by one, add different connection types to the enum
* expose the `conn_type` on CNode, and use this to reduce reliance on flags (& asserts)
* fix the bug in counting different type of connections
* some additional cleanup to simplify logic and make expectations explicit/inclusive rather than implicit/exclusive.
ACKs for top commit:
jnewbery:
utACK 01e283068b
laanwj:
Code review ACK 01e283068b, the commits are pretty straightforward to follow, and I think this is a move in the right direction overall
vasild:
ACK 01e283068
sdaftuar:
ACK 01e283068b.
fanquake:
ACK 01e283068b - I don't have as much experience with the networking code but these changes look fairly straight forward, the new code seems more robust/understandable and the additional documentation is great. I'm glad that a followup branch is already underway. There might be some more review comments here later today, so keep an eye on the discussion, however I'm going to merge this now.
jb55:
wow this code was messy before... ACK 01e283068b
Tree-SHA512: 7bb644a6ed5849913d777ebc2ff89133ca0fbef680355a9a344e07496a979e6f9ff21a958e8eea93dcd7d5c343682b0c7174b1a3de380a4247eaae73da436e15
0a8aa626dd refactor: Make HexStr take a span (Wladimir J. van der Laan)
Pull request description:
Make `HexSt`r take a span of bytes, instead of an awkward pair of templated iterators. This simplifies most of the uses.
ACKs for top commit:
elichai:
Code review ACK 0a8aa626dd
hebasto:
re-ACK 0a8aa626dd
jonatack:
re-ACK 0a8aa626dd
Tree-SHA512: 6e178ece5cbac62119c857a10299b1e85422938084c3f03063e17119a5129e0c28016e05a6fabaa4c271a7e0a37c7cd89fa47c435ee19b38a5acfe80d00de992
edc316020e test: Remove duplicate NodeContext hacks (Russell Yanofsky)
Pull request description:
Qt tests currently are currently using two NodeContext structs at the same time, one in interfaces::NodeImpl::m_context, and the other in BasicTestingSetup::m_node, and the tests have hacks transferring state between them.
Fix this by getting rid of the NodeImpl::m_context struct and making it a pointer. This way a common BitcoinApplication object can be used for all qt tests, but they can still have their own testing setups.
Non-test code is changing but non-test behavior is still the same as before.
Motivation for this PR is to be able to remove the "std::move(test.m_node.connman)" and mempool hacks for swapping individual NodeContext members in Qt tests, because followup PR #19099 adds yet another member (wallet_client) that needs to be swapped. After this change, the whole NodeContext struct can be swapped instead of individual members, so the workarounds are less fragile and invasive.
ACKs for top commit:
MarcoFalke:
crACK edc316020e🌮
promag:
ACK edc316020e.
Tree-SHA512: c1650e4127f43a4020304ca7c13b5d9122fb5723aacd8fa1cf855d03c6052fcfb7685810aa2a5ef708561015f0022fecaacbad479295104ca45d2c17579466a4
31cf68a3ad [util] add RunCommandParseJSON (Sjors Provoost)
c17f54ee53 [ci] use boost::process (Sjors Provoost)
32128ba682 [doc] include Doxygen comments for HAVE_BOOST_PROCESS (Sjors Provoost)
3c84d85f7d [build] msvc: add boost::process (Sjors Provoost)
c47e4bbf0b [build] make boost-process opt-in (Sjors Provoost)
929cda5470 configure: add ax_boost_process (Sjors Provoost)
8314c23d7b [depends] boost: patch unused variable in boost_process (Sjors Provoost)
Pull request description:
Prerequisite for external signer support in #16546. Big picture overview in [this gist](https://gist.github.com/Sjors/29d06728c685e6182828c1ce9b74483d).
This adds a new dependency [boost process](https://github.com/boostorg/process/tree/boost-1.64.0). This is part of Boost since 1.64 which is part of `depends`. Because the minimum Boost version is 1.47, this functionality is skipped for older versions of Boost.
Use `./configure --with-boost-process` to opt in, which checks for the presence of Boost::Process.
We add `UniValue runCommandParseJSON(const std::string& strCommand)` to `system.{h,cpp}` which calls an arbitrary command and processes the JSON returned by it. This is currently only called by the test suite.
~For testing purposes this adds a new regtest-only RPC method `runcommand`, as well as `test/mocks/command.py` used by functional tests.~ (this is no longer the case)
TODO:
- [ ] review boost process in #15440
ACKs for top commit:
achow101:
ACK 31cf68a3ad
hebasto:
re-ACK 31cf68a3ad, only rebased (verified with `git range-diff`) and removed an unintentional tab character since the [previous](https://github.com/bitcoin/bitcoin/pull/15382#pullrequestreview-458371035) review.
meshcollider:
Very light utACK 31cf68a3ad, although I am not very confident with build stuff.
promag:
Code review ACK 31cf68a3ad, don't mind the nit.
ryanofsky:
Code review ACK 31cf68a3ad. I left some comments below that could be ignored or followed up later. The current change is clean and comprehensive.
Tree-SHA512: c506e747014b263606e1f538ed4624a8ad7bcf4e025cb700c12cc5739964e254dc04a2bbb848996b170e2ccec3fbfa4fe9e2b3976b191222cfb82fc3e6ab182d
63e9e40b73 test: Add LockStackEmpty() (Hennadii Stepanov)
42b2a95373 test: Repeat deadlock tests (Hennadii Stepanov)
1f96be25b0 Preserve initial state if push_lock() throws exception (Hennadii Stepanov)
Pull request description:
On master (e3fa3c7d67) if the `push_lock()` throws the "potential deadlock detected" exception (via the `potential_deadlock_detected()` call), the `LockData` instance internal state differs from one when the `push_lock()` was called. This non-well behaviour makes (at least) testing brittle.
This PR preserves the `LockData` instance initial state if `push_lock()` throws an exception, and improves the `sync_tests` unit test.
ACKs for top commit:
MarcoFalke:
re-ACK 63e9e40b73
vasild:
ACK 63e9e40
Tree-SHA512: 7679182154ce5f079b44b790faf76eb5f553328dea70a326ff6b600db70e2f9ae015a33a104ca070cb660318280cb79b6b42e37ea5166f26f9e627ba721fcdec
