Update libmultiprocess subtree to be more stable with rust IPC client #34422

1. 
   ryanofsky commented at 8:06 pm on January 27, 2026: contributor

   This is based on #34284 + https://github.com/bitcoin-core/libmultiprocess/pull/240 so is currently a draft PR. It’s open to make sure the changes work together and there are no issues in CI.

   Includes:

   • https://github.com/bitcoin-core/libmultiprocess/pull/241
   • https://github.com/bitcoin-core/libmultiprocess/pull/240

   The latter change fixes issues with asynchronous requests (https://github.com/bitcoin/bitcoin/issues/33923) and unclean disconnects (https://github.com/bitcoin/bitcoin/issues/34250) that happen with the rust mining client.

   The changes can be verified by running test/lint/git-subtree-check.sh src/ipc/libmultiprocess as described in developer notes and lint instructions

2. Squashed 'src/ipc/libmultiprocess/' changes from 1fc65008f7d..1d7debfa8ea

   1d7debfa8ea Prevent crash on unclean disconnect if abandoned IPC call returns interface pointer
   d43f965e2fc Allow simultaneous calls on same Context.thread
   3a69d4755af Merge bitcoin-core/libmultiprocess#241: doc: Bump version number v7 -> v8
   0ade1b40ac5 doc: Bump version number
   
   git-subtree-dir: src/ipc/libmultiprocess
   git-subtree-split: 1d7debfa8ea9a5eddfcf3f8bb694e4971e04d61d

   e8ce15740b
3. ipc, test: Add tests for unclean disconnect and thread busy behavior

   Upcoming libmultiprocess changes are expected to alter this behavior
   (https://github.com/bitcoin/bitcoin/issues/34250#issuecomment-3749243782),
   making test coverage useful for documenting current behavior and validating the
   intended changes.

   937042acf5
4. Merge commit 'e8ce15740b196b7ad000ec2518e91edcbb10d671' into pr/subtree-8 13ced49b80
5. pr/ipc-testasync after fixes 514857303d
6. 
   DrahtBot commented at 8:06 pm on January 27, 2026: contributor

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

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/34422.

   Reviews

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

   LLM Linter (✨ experimental)

   Possible typos and grammar issues:

   • “is is signaled” -> “is signaled” [duplicate word “is” makes the sentence confusing]

   2026-01-28 01:27:57

7. DrahtBot added the label CI failed on Jan 27, 2026
8. 
   DrahtBot commented at 9:02 pm on January 27, 2026: contributor

   🚧 At least one of the CI tasks failed. Task lint: https://github.com/bitcoin/bitcoin/actions/runs/21412348994/job/61652239701 LLM reason (✨ experimental): Python lint errors (unused imports) detected by ruff caused the CI to fail.

   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.

9. ryanofsky force-pushed on Jan 28, 2026
10. 
    ryanofsky commented at 1:28 am on January 28, 2026: contributor

    Updated 08576a1cd8db4d995b9b4c315e13c63de835210f -> 514857303df32b9e3bf69e5639186eedebb24999 (pr/subtree-8.1 -> pr/subtree-8.2, compare) to fix CI lint and tsan errors https://github.com/bitcoin/bitcoin/actions/runs/21412348994

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