Bitcoin Core

lint: remove E731 Ruff ignore

Replace assigned lambdas with local functions so Ruff can enforce E731.
For platform-specific immutable file cleanup, store the command as data
instead of creating conditional callbacks.

lint: remove E712 Ruff ignore

Use identity checks for literal false values to preserve RPC semantics.

ipc, moveonly: combine ipc_test.cpp and ipc_tests.cpp

Previously ipc_test.cpp contained tests which depended on
libmultiprocess and ipc_tests.cpp contained tests which didn't.
Separation was needed because libmultiprocess tests need to be built
with additional include and link paths, and cmake only has good support
for setting these on libraries, not source files. The separation also
allowed the add_boost_test custom cmake function to work with no changes,
because it could find the boost test registration in ipc_tests.cpp, and
then ipc_tests.cpp would run the tests in ipc_test.cpp without them
needing to be registered in boost.

But with windows support being added, the parse address test can't
easily avoid a dependecy on libmultiprocess, because it depends on the
ipc/process.h header, and ipc/process.h header will now need
platform-specific ProcessId and SocketId types defined by
libmultiprocess, rather than plain ints.

With all ipc tests depending on libmultiprocess, there is not really a
rationale for having separate test files anymore, so this change
combines them, and move the cmake add_boost_test function definition so
it can be used instead of target_sources to register ipc_tests.cpp with
ctest.

The change prevents CI errors from including ipc/process.h in
ipc_tests.cpp:

In file included from /Users/runner/work/bitcoin/bitcoin/repo_archive/src/ipc/test/ipc_tests.cpp:5:
In file included from /Users/runner/work/bitcoin/bitcoin/repo_archive/src/ipc/process.h:11:
/Users/runner/work/bitcoin/bitcoin/repo_archive/src/ipc/util.h:14:10: fatal error: 'kj/debug.h' file not found
14 | #include <kj/debug.h>

https://github.com/bitcoin/bitcoin/actions/runs/24465865499/job/71492617687?pr=35084

ipc, refactor: Change Protocol class field order

This just changes Protocol class field order to make sure class members are not
destroyed before the event loop thread exits. There is no change in behavior.
The change is just being made to clarify intent and avoid potential bugs.

ipc, refactor: use native path separators in test

Avoid hardcoded forward slashes is ParseAddress test, use native path
separators instead.

ipc, refactor: fix include order

Keep standard headers separate from posix headers

ipc: Avoid 'unistd.h' error with MSVC

Avoid compile error from MSVC:

D:\a\bitcoin\bitcoin\src\ipc\interfaces.cpp(24,1): error C1083: Cannot open include file: 'unistd.h': No such file or directory

MinGW provides this header but MSVC does not. Header is unneeded on windows
because HandleCtrlC code that uses it is not compiled on windows.

ipc, refactor: Add ProcessId type alias and use it

Use ProcessId type instead of int to represent process ids to be
compatible with an upcoming version of libmultiprocess which adds
windows support.

ipc, refactor: Add SocketId type alias and use it

Use SocketId type instead of int to represent socket ids to be
compatible with an upcoming version of libmultiprocess which adds
windows support.

ipc, refactor: Add Stream type alias and use it

Use Stream type to abstract socket ids and be compatible with updated
mp::ConnectStream() and mp::ServeStream() functions that use streams
instead of socket ids in an upcoming version of libmultiprocess which
adds windows support.

Since creating Stream objects from socket ids can require the event loop
to be running, the ipc::Protocol::serve() method is also updated to
accept the server stream though a callback parameter instead of a normal
parameter.

ipc, refactor: Drop connect/listen/serve exe_name parameters

Pass exe_name parameter to ipc::Protocol class constructor instead. It never
really made sense to have exe parameters as part of the protocol interface and
removing them makes adding new features like windows support easier.

The exe name values are only used for logging and debuggging purposes to
distinguish log messages from different processes.

fuzz: Drop unnecessary mutexes

Remove the `Mutex` from the `coins_view` and `coinscache_sim`
pool startup helpers. Fuzz targets are entered sequentially within a
process and parallel fuzzing uses separate processes/forks, which each
have their own copy of the global thread pool. Therefore, a mutex to
prevent two in-process callers from racing to start the pool isn't needed.

clusterlin: avoid heap allocations in GetLinearization

Replace GetLinearization's four per-call heap-allocated vectors (the
ready chunk/transaction heaps and both dependency counters) with stack
arrays and explicit size counters. This especially benefits
linearization of small clusters, where the allocations make up a
significant fraction of the total runtime.

clusterlin: reserve the suboptimal-chunk queue up front

Reserve capacity for one entry per transaction in m_suboptimal_chunks at
construction time, avoiding repeated reallocations while MakeTopological
and StartOptimizing fill the queue.

clusterlin: avoid recomputing intersections in MergeChunks

MergeChunks scans the top chunk's transactions twice: once to count
the dependencies on the bottom chunk, and once to locate the randomly
picked one. Remember the per-transaction dependency counts from the
first pass, so the second pass only computes the intersection of the
selected transaction, rather than one per transaction scanned.

depends: Update Qt to 6.8.4

fuzz: clang-format LIMITED_WHILE

This is a whitespace-only clang-format change.

To verify it, one can run:

```sh
(git show | git apply --reverse ) && ( git diff -U0 | ./contrib/devtools/clang-format-diff.py -p1 -i -v ) && git diff HEAD
```

A few minor, non-macro formatting adjustments were made in touched files:

* `src/wallet/test/fuzz/crypter.cpp`: Removed a redundant double semicolon
* `src/test/fuzz/txorphan.cpp`: Corrected indentation on an `else if` block.
* `src/test/fuzz/mini_miner.cpp`: Removed an unnecessary empty line.

fuzz: Clang-format LIMITED_WHILE like while

fuzz: Remove unused workaround after fix in libmultiprocess byte-span serializer

fuzz: Use LIMITED_WHILE over for-loop with consumed size integral

This is a style cleanup. The general pattern to use `LIMITED_WHILE`,
which all other fuzz tests use, has some benefits:

* When no data is available, a simple and single (let's say) 64 value in
the fuzz input will not result in 64 loops over the same body with the
same default/fallback values.
* When no data is available, `ConsumeBool` falls back to `false` and
breaks the loop early.
* When further data is available, the overhead is just a single byte,
making it also possibly easier for the fuzz engine to mutate the data,
as a single int that influences the whole remainder of the fuzz input
can lead to the 'havoc' effect.
* When a crash is reduced, deleting bytes will directly influence the
execution length, so byte-length of the fuzz input roughly corresponds
to run-time length.

Squashed 'src/ipc/libmultiprocess/' changes from 28e056576a..e8de5c7b68

e8de5c7b68 Merge bitcoin-core/libmultiprocess#305: refactor: memcpy to std::ranges::copy to work around ubsan warn
9307e68e5a Merge bitcoin-core/libmultiprocess#306: doc: Bump version 12 > 13
fac7b9b7f6 refactor: memcpy to std::ranges::copy to work around ubsan warn
1bd7025609 Merge bitcoin-core/libmultiprocess#297: test: add map serialization round-trip coverage
438fdd243d doc: Bump version 12 > 13
463d073cb8 test: rename vBool to vector_bool
85df233845 test: add mapStringInt to foo.capnp to cover map serialization and deserialization

git-subtree-dir: src/ipc/libmultiprocess
git-subtree-split: e8de5c7b68e0ae21c94ae92aa22e5c3b213f9c12

ci: use uv 11.x

ci: use Ubuntu 26.04 for lint container

ci: mypy 2.3.0

ci: disable Qt build in OpenBSD cross job

Disable this for now, until issues with llvm-ranlib, and gui deps are
fixed:
```bash
libtool: install: chmod 644 /home/runner/work/_temp/depends/work/staging/x86_64-unknown-openbsd/fontconfig/2.12.6-a12d0a13377/home/runner/work/_temp/depends/x86_64-unknown-openbsd/lib/libfontconfig.a
libtool: install: llvm-ranlib-22 -t /home/runner/work/_temp/depends/work/staging/x86_64-unknown-openbsd/fontconfig/2.12.6-a12d0a13377/home/runner/work/_temp/depends/x86_64-unknown-openbsd/lib/libfontconfig.a
llvm-ranlib-22: error: Invalid option: '-t'
make[4]: *** [Makefile:539: install-libLTLIBRARIES] Error 1
```