[31.x] Backports #35331

1. 
   fanquake commented at 1:03 PM on May 20, 2026: member

   Backports:

   • #34953
   • #35228
   • #35279
   • #35313 (only https://github.com/bitcoin-core/leveldb-subtree/pull/61)
   • #35316
   • #35378
   • #35348
   • #35408
   • #35410
   • #35430
   • #35447
2. psbt, test: remove address type restrictions in test

   Because the corresponding Taproot fields were added in PSBT in PR 22558, so
   these restrictions are no longer necessary.
   
   Github-Pull: #35279
   Rebased-From: 81348576cc411a63da295a10a3846302419a18e0

   101071722e
3. DrahtBot added the label Backport on May 20, 2026
4. fanquake added this to the milestone 31.1 on May 20, 2026
5. 
   DrahtBot commented at 1:03 PM on May 20, 2026: contributor

   <!--e57a25ab6845829454e8d69fc972939a-->

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   <!--006a51241073e994b41acfe9ec718e94-->

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35331.

   <!--021abf342d371248e50ceaed478a90ca-->

   Reviews

   See the guideline for information on the review process. A summary of reviews will appear here.

   <!--5faf32d7da4f0f540f40219e4f7537a3-->

   LLM Linter (✨ experimental)

   Possible typos and grammar issues:

   • overriden -> overridden [misspelling in the release note]

   ^{2026-06-04 10:10:20}

6. wallet: use outpoint when estimating input size

   `CalculateMaximumSignedInputSize()` is passed the outpoint being sized, but that context was not used when estimating the signed input size.
   Pass the outpoint through so externally selected inputs are not underestimated.
   
   Co-authored-by: Antoine Poinsot <darosior@protonmail.com>
   
   Github-Pull: #35228
   Rebased-From: cd8d3bd937b5515ea000408eb07d2ae3cd1aa417

   671e6c2c33
7. fanquake force-pushed on May 20, 2026
8. DrahtBot added the label CI failed on May 20, 2026
9. DrahtBot removed the label CI failed on May 20, 2026
10. musig: Reject empty pubkey list in GetMuSig2KeyAggCache

    Github-Pull: #35316
    Rebased-From: 8ce84321ceaf16c0ee3418d30011c357fdc46deb

    d61687a2ac
11. fanquake force-pushed on May 22, 2026
12. DrahtBot added the label CI failed on May 22, 2026
13. ci: switch to GitHub cache for all runners

    Cirrus is winding down and github now offers more than 10GB cache.
    
    Switch to GH cache for all runner-types. Simplify docker build arg
    construction, and reduce the number of needed action permissions.
    
    Github-Pull: #35348
    Rebased-From: c03107acf50aeada1bacdfdbf632ffce2957bff0

    3440027b7d
14. fanquake force-pushed on May 22, 2026
15. DrahtBot removed the label CI failed on May 22, 2026
16. Disable seek compaction

    Seek compaction is causing a cascade effect in the chainstate DB, causing large parts of the database to be rewritten every ~hour.
    
    Every periodic flush writes around 2 MiB. Since this is roughly the `write_buffer_size`, these writes regularly cause the memtable to rotate into a small L0 file. This file has a small seek budget, and with the random UTXO reads done during validation, it can get scheduled for seek compaction quickly.
    
    That seek compaction pushes the small file down to L1. Since most UTXOs are already lower down in L4/L5, many reads that consult this file do not find the key there and continue downward. The bloom filter makes those misses cheap, but LevelDB still decrements the file's seek budget. The file then gets scheduled for another seek compaction, and the same pattern pushes it down through L2 and L3.
    
    The expensive part happens around L3/L4. L4 has many ~32 MiB files holding the bulk of the UTXO set. When LevelDB compacts into L3, it may split the output into many smaller L3 files to limit how much L4 "grandparent" data any one output overlaps. Each of these small L3 files then gets its own small seek budget. Because chainstate keys are hash-random, each small L3 file can still have a broad key range, so many random reads consult it and quickly drain its budget. Once seek-compacted into L4, each tiny L3 file can overlap many L4 files, so compacting a few hundred KiB from L3 can require rewriting hundreds of MiB from L4. Repeating that across many small L3 files can rewrite most of the chainstate.
    
    This is a poor fit for chainstate because UTXO keys are hash-random, the DB is large enough to have many levels, writes are relatively small and periodic, and reads are frequent. The result is that read misses trigger compactions much earlier than size pressure would, and those compactions have very high write amplification.
    
    Disabling seek compaction may leave more files in upper levels for longer, so reads could theoretically consult more files. But Bitcoin Core enables bloom filters for all its LevelDB instances, so these misses are usually cheap in-memory filter checks rather than disk reads.
    
    For the other DBs, the risk is much smaller. They also use bloom filters, and most are smaller and less read-heavy. With fewer levels and less random read pressure, disabling seek compaction should have little effect there.
    
    Co-authored-by: l0rinc <pap.lorinc@gmail.com>

    7c0fa17a68
17. fanquake force-pushed on May 28, 2026
18. DrahtBot added the label CI failed on May 28, 2026
19. 
    DrahtBot commented at 4:05 PM on May 28, 2026: contributor

    <!--85328a0da195eb286784d51f73fa0af9-->

    🚧 At least one of the CI tasks failed. _{Task lint: https://github.com/bitcoin/bitcoin/actions/runs/26580148981/job/78317916896} _{LLM reason (✨ experimental): CI failed the lint check “subtree” because a subtree directory was modified without a corresponding subtree merge.}

    <details><summary>Hints</summary>

    Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

    • Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.

    • A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.

    • An intermittent issue.

    Leave a comment here, if you need help tracking down a confusing failure.

    </details>

20. ci: switch runners from cirrus to warpbuild

    Github-Pull: #35378
    Rebased-From: 4bdd46ace37f02da062a53a2943caeddca4ed8f9

    6f1ff568fe
21. fanquake force-pushed on May 28, 2026
22. crypto: disable ASan instrumentation of SSE4 SHA256 for GCC

    The existing Clang-only no_sanitize("address") guard is extended to
    also cover GCC.  When GCC compiles this file with -fsanitize=address
    in debug builds, the instrumented inline assembly causes a SEGV during
    SHA256AutoDetect()'s self-test on CPUs that use the SSE4 code path
    (i.e. those without SHA-NI support), regardless of optimization level.
    
    The original Clang code placed the attribute between the function
    declarator and the opening brace.  GCC's Attribute Syntax
    documentation notes that this position in a function definition
    "may, in future, be permitted," so it is not currently supported.
    The attribute is moved to the start of the function definition,
    which is valid form for both GCC and Clang.
    
    The preprocessor guards are restructured so each compiler branch is
    explicit: __clang__ with __has_feature, and __GNUC__ with
    __SANITIZE_ADDRESS__.
    
    Github-Pull: #34953
    Rebased-From: fedeff7f201df0206eefb744ad125e44a63a3ea0

    8dc6d13362
23. doc: remove reference to cirrus

    Github-Pull: #35408
    Rebased-From: 265563bf75c0b8b615e28d47398098020ff0b109

    3855e5b0b7
24. ci: use ubuntu-latest instead of ubuntu-24.04

    To match the usage of -latest for the warp runners.
    
    Github-Pull: #35408
    Rebased-From: 5700a61b73342b506b0114b342499da7642c1c10

    aa12648e1c
25. fanquake force-pushed on May 29, 2026
26. fanquake force-pushed on May 29, 2026
27. ci: Add dynamic cache switching to warp cache

    The GHA cache is very slow, taking on the order of minutes to save and
    restore from.
    
    Use WarpBuild's cache instead as this is in the same region and much
    faster.
    
    WarpBuild cache action does not auto-fallback to GHA if not being run on
    Warp. To allow fork runs to fallback to GHA caching, whilst minimising
    duplication in the action files, create new "interal" actions which
    perform the switching logic, and use these in the (renamed) cache|save
    actions.
    
    Without this we would need the `if` logic in our prvious actions, 4
    times in each of save and restore.
    
    Plumb the provider through into the action, as a composite action can't
    read `env` (`GITHUB_OUTPUT`) from previous steps.
    
    Github-Pull: #35430
    Rebased-From: 2ce4ae7d8f006959cb83be93a17b8125e953c30a

    c1bf1c0049
28. fanquake force-pushed on Jun 2, 2026
29. ci: use Warp cache for Docker layers

    Speeds of 1MB/s and 15 minute cached docker image pulls during builds
    are not uncommon.
    
    Warp runners provide a local GitHub Actions cache protocol proxy for
    Docker layer cache traffic. Point BuildKit's gha cache backend at that
    proxy on Warp runners so cached image layers do not have to be fetched
    from GitHub's slower cache service.
    
    Add a default for provider so other users (e.g. qa-assets) don't have to
    update this unless they use custome runners.
    
    Github-Pull: #35447
    Rebased-From: 82901981bfbaeb3f41956597e6d90daa59a0c078

    d87cd03049
30. fanquake force-pushed on Jun 4, 2026
31. net: use the proxy if overriden when doing v2->v1 reconnections

    `OpenNetworkConnection()` supports overriding the proxy to use for
    connecting. However when v2 connection is attempted and it fails a v1
    connection is tried without that proxy.
    
    Store the override proxy in `CNode` and pass it to
    `CConnman::m_reconnections` to be used for v1 retries.
    
    Github-Pull: #35410
    Rebased-From: fd230f942d8377cafcc346f1605d5aa00db2cc40

    0fee0c2c49
32. net: ensure no direct private broadcast connections

    Private broadcast connections use either Tor or I2P, which require a
    proxy intrinsically or IPv4 or IPv6 which must use a proxy in the
    context of private broadcast to avoid leaking the originator's IP
    address.
    
    Add a safety check to guard against future mistakes.
    
    Co-authored-by: Andrew Toth <andrewstoth@gmail.com>
    
    Github-Pull: #35410
    Rebased-From: d01b461f71e255dcb5d7d0ee84a560f26cfe0b6f

    7f5b249bae
33. test: make reusable SOCKS5 server starting

    Extract the part of `p2p_private_broadcast.py` that configures and
    starts the SOCKS5 server into a reusable function and put it into
    `test_framework/socks5.py`.
    
    Use bind port 0 to let the OS pick an available port instead of
    hackishly assuming that `p2p_port(N)` is available where N is more
    than the number of the nodes the test uses.
    
    Github-Pull: #35410
    Rebased-From: 2ffa81fac40fd4d03bdcfd37479a6f3305afb483

    cbcdc6ebb0
34. test: make reusable starting a standalone P2P listener

    Extract the part of `p2p_private_broadcast.py` that starts
    listening on a `P2PConnection` object (or its children classes)
    and put it into `test_framework/p2p.py`.
    
    Github-Pull: #35410
    Rebased-From: 2333be9cbc58dd2a533c9bd604b9db593b1d96a7

    eef53ad20a
35. test: make reusable filling of a node's addrman

    Extract the part of `p2p_private_broadcast.py` that fills a given node's
    addrman and put it into `test_framework/test_framework.py`.
    
    Github-Pull: #35410
    Rebased-From: ab35a028eded00008841a3ec8662823090bfc68b

    31ccc9165f
36. test: add a regression test for private broadcast v1 retries

    Github-Pull: #35410
    Rebased-From: 5a3756d150fc095d0038592c6338225db48fd4b5

    0e1f3a7d15
37. net: un-default the OpenNetworkConnection()'s proxy_override argument

    This way callers will not forget to set it.
    
    Github-Pull: #35410
    Rebased-From: bf0d257c11bebc42b88b7e96368ed2be48bc0ad1

    bf728e6f6b
38. doc: update release notes for v31.x 67d4028c83
39. fanquake force-pushed on Jun 4, 2026

Milestone
31.1