. #35280

Remove all CMake options, modules, and deployment logic related to the
Qt GUI: BUILD_GUI, WITH_QRENCODE, WITH_DBUS, BUILD_GUI_TESTS, Qt 6.2
package discovery, FindQt.cmake, FindQRencode.cmake, the macOS app
bundle deploy target, and share/qt translation/plist files. Update the
Windows NSIS installer and ENABLE_IPC description accordingly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Remove src/qt/test/ entirely and clean up references to test_bitcoin-qt
in src/test/README.md and doc/files.md.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Delete the entire src/qt/ directory, both GUI init implementations
(bitcoin-qt.cpp, bitcoin-gui.cpp), the Qt translation lint script, and
the Qt translation process doc. Update all references to bitcoin-qt and
bitcoin-gui throughout source files, CI scripts, contrib tools, and
documentation.

Remove -DBUILD_GUI=OFF and Qt package dependencies from CI scripts,
drop -DBUILD_GUI_TESTS=OFF from guix and libmultiprocess build scripts,
delete the Transifex config, and remove translation workflow references
from README, CONTRIBUTING, and release docs.

Remove the GUI

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* nuke: assumeutxo (commit 1 of 3) - drop user-facing surface

Delete loadtxoutset and getchainstates RPCs, empty all chains' m_assumeutxo_data,
drop feature_assumeutxo.py, tool_bitcoin_chainstate.py and utxo_snapshot fuzz target,
delete the now-orphan snapshot-related unit tests.

The snapshot machinery (ActivateSnapshot, PopulateAndValidateSnapshot, etc.) is
still in place but unreachable from outside the binary. Removed in the next commit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* nuke: assumeutxo (commit 2 of 3) - rip snapshot machinery

Delete AssumeutxoHash/AssumeutxoData/AssumeutxoForHeight/ForBlockhash and
GetAvailableSnapshotHeights from chainparams. Delete ChainstateRole, the
Assumeutxo enum, SnapshotMetadata, SnapshotCompletionResult, and the
m_from_snapshot_blockhash / m_target_blockhash / m_target_utxohash /
m_cached_snapshot_base / m_cached_target_block members on Chainstate.

Drop ActivateSnapshot, PopulateAndValidateSnapshot, MaybeValidateSnapshot,
DetectSnapshotChainstate, ActivateExistingSnapshot, HistoricalChainstate,
ValidatedChainstate, RemoveChainstate, LoadAssumeutxoChainstate,
ValidatedSnapshotCleanup, GetBackgroundVerificationProgress and the
snapshot-aware paths in CheckBlockIndex / LoadBlockIndex / LoadChainTip /
UpdateTipLog / MaybeRebalanceCaches.

Delete BLOCK_ASSUMED_VALID, BlockManager::m_snapshot_height, the
per-snapshot blockfile cursor array, and the NODE_NETWORK-flip on
snapshot load.

Drop the ChainstateRole parameter from BlockConnected and
ChainStateFlushed across validationinterface, node/interfaces,
zmqnotificationinterface, bitcoinkernel. Drop Chain::hasAssumedValidChain.

ChainstateManager still holds std::vector<std::unique_ptr<Chainstate>>
m_chainstates with exactly one entry; commit 3 collapses that to a
single unique_ptr.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* nuke: assumeutxo (commit 3 of 3) - collapse m_chainstates to single chainstate

ChainstateManager::m_chainstates was a std::vector<std::unique_ptr<Chainstate>>
that could hold up to two chainstates (one snapshot-based, one background).
With the snapshot machinery gone, replace it with a single
std::unique_ptr<Chainstate> m_chainstate.

Rewrite every `for (auto& cs : m_chainstates)` loop to operate on the sole
chainstate directly. InitializeChainstate / ActiveChainstate / ActivateBestChains /
ResetChainstates simplified accordingly, plus the matching call sites in
init.cpp, node/chainstate.cpp, kernel/bitcoinkernel.cpp,
test/util/validation.cpp, and the consistency checks in CheckBlockIndex.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Remove the REST interface

Adds a binary that fetches Bitcoin Core's master branch, finds the
common ancestor with the current branch, then attempts to cherry-pick
each merged PR (merge commits) in order. Conflicts are logged and
skipped; the tool continues to the end and prints a summary.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

2424e5283672e10bc45cdbca1a8851308716b50c lint: doc: detail lint tool install methods (will)
5fefa5a654e2a1146c8abc9673e72d7bcbf2f757 Don't pin Python patch version (Sjors Provoost)
fd15b55c2ef607525d45f26ab3e7f3fc600e29af lint: use requirements.txt (will)
5f4d3383daa064d188ef8c6b1d9adbad3a67bcb6 lint: switch to ruff for formatting and linting (will)
a53b81ce4e649dd637a217686745a6f6c6c81ca5 lint: switch to uv for python management in linter (will)

Pull request description:

  Modernise our lint tooling by:

  \- Replacing pyenv + pip with [uv](https://docs.astral.sh/uv/) for better Python environment and dependency management
  \- Move uv ruff and ty to install via `COPY --from` multi-stage Docker image imports
  \- Moving ruff lint rules from hardcoded Rust array (in lint_py.rs) into a top-level ruff.toml
  \- Extracting all remaining pip dependencies into dedicated ci/lint/requirements.txt

  Extra rationale:

  `COPY --from` pulls pre-built binaries from upstream images instead of compiling/downloading at runtime. Containerfile layer optimisations reduce rebuild frequency further.

  Pinning tool versions in the dockerfile makes it more excplicit and easier to find.

  The tradeoff we make here is that there is no longer a single install script to install tooling on a local machine. However I think this is OK, as it currently only works for `apt`-based OSes anyway, and I don't think running the linter outside of the container is such a valuable use-case as it is with some of the other CI jobs.

ACKs for top commit:
  maflcko:
    review ACK 2424e5283672e10bc45cdbca1a8851308716b50c 🗿
  sedited:
    ACK 2424e5283672e10bc45cdbca1a8851308716b50c

Tree-SHA512: 32ef989c1e241cebe5f13da10abd23f6f63306591fd1f81880d688b886082bca17987591dc592c41fbb72278eba57b3cc6e786de7cfa80eb490ab34465d0119b
(cherry picked from commit 09a9bb3536718d0dffa6f797ddff907df6ef94f9)

fa9c919678c0d4926ff735eecf12562d99a7e691 refactor: Use ignore-list over verbose select-list (MarcoFalke)
fa9b01adecce7d2e2f0091a363bcf98cf5d5c378 ci: Enable ruff ambiguous-unicode-character checks (MarcoFalke)

Pull request description:

  Ambiguous unicode chars are unused and confusing. Worst, they can lead to bugs.

  So enable the ruff checks to catch them. Can be tested via:

  ```
  echo 'ZGlmZiAtLWdpdCBhL3Rlc3QvZnVuY3Rpb25hbC93YWxsZXRfZGlzYWJsZS5weSBiL3Rlc3QvZnVu
  Y3Rpb25hbC93YWxsZXRfZGlzYWJsZS5weQppbmRleCBkYmNjY2Q0Li4wYjhjNDQ2IDEwMDc1NQot
  LS0gYS90ZXN0L2Z1bmN0aW9uYWwvd2FsbGV0X2Rpc2FibGUucHkKKysrIGIvdGVzdC9mdW5jdGlv
  bmFsL3dhbGxldF9kaXNhYmxlLnB5CkBAIC0yMSwzICsyMSw4IEBAIGNsYXNzIERpc2FibGVXYWxs
  ZXRUZXN0IChCaXRjb2luVGVzdEZyYW1ld29yayk6CiAgICAgZGVmIHJ1bl90ZXN0IChzZWxmKToK
  KyAgICAgICAgIiIiQSBsb3ZlbHkgZG9jc3RyaW5nICh3aXRoIGEgYFUrRkYwOWAgcGFyZW50aGVz
  aXPvvIkuIiIiCiAgICAgICAgICMgTWFrZSBzdXJlIHdhbGxldCBpcyByZWFsbHkgZGlzYWJsZWQK
  KyAgICAgICAgIyBu0L5xYSAgIzwtIGlzIEN5cmlsbGljIChgVSswNDNFYCkKKyAgICAgICAgcHJp
  bnQoIs6XZWxsbywgd29ybGQhIikgICMgPC0gaXMgdGhlIEdyZWVrIGV0YSAoYFUrMDM5N2ApLgor
  ICAgICAgICBleGFtcGxlID0gInjigI8iICogMTAwICAjICAgICLigI94IiBpcyBhc3NpZ25lZAor
  ICAgICAgICBleGFtcGxlPU5vbmUjbm9xYQogICAgICAgICBhc3NlcnRfcmFpc2VzX3JwY19lcnJv
  cigtMzI2MDEsICdNZXRob2Qgbm90IGZvdW5kJywgc2VsZi5ub2Rlc1swXS5nZXR3YWxsZXRpbmZv
  KQo=' | base64 --decode | git apply

  git diff

  ruff check ./test/functional/*.py
  ```

  It should print 4 error types.

ACKs for top commit:
  stickies-v:
    ACK fa9c919678c0d4926ff735eecf12562d99a7e691
  willcl-ark:
    ACK fa9c919678c0d4926ff735eecf12562d99a7e691

Tree-SHA512: de226ec2feaf65a0a8b15606708cc390296be4492f41221f8a49f034b16e8fb62125342c6993f9d5c76bd4ae2db7343851b252a1b9140e27d6777f19a0b1605e
(cherry picked from commit 82733e61deea24cfd344aed36020675a15cc672e)

Daily cherry pick

Track which upstream merge commits were previously cherry-picked by
scanning our branch's commit messages for the "(cherry picked from
commit <hash>)" trailers written by -x. Switch the upstream log format
from --oneline to --format=%H %s so full hashes are used throughout,
ensuring reliable comparison against the stored trailers.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

contrib: cherry-pick-upstream: skip already-applied commits

Removes test/functional entirely, along with all CI invocations,
documentation, build-system hooks, and contrib scripts that depended on
it (contrib/testgen, contrib/message-capture).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

The cycle node/utxo_snapshot -> validation -> node/utxo_snapshot no
longer exists and can be removed from EXPECTED_CIRCULAR_DEPENDENCIES.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>