bd9e0e65f5
fcaec2544b32226fd5357a88506fe080058d25bc doc: release note for IPC cooldown and interrupt (Sjors Provoost) 1e82fa498cf4881466f0539146c101242b9dc30d mining: add interrupt() (Sjors Provoost) a11297a9048e0d910915e1a37b2be467c057a78d mining: add cooldown argument to createNewBlock() (Sjors Provoost) Pull request description: As reported in #33994, connected mining clients will receive a flood of new templates if the node is still going through IBD or catching up on the last 24 hours. This PR fixes that using an _optional_ cooldown mechanism, only applied to `createNewBlock()`. First, cooldown waits for IBD. Then, as the tip keeps moving forward, it waits a few seconds to see if the tip updated. If so, it restarts the timer and waits again. The trade-offs for this mechanism are explained below. Because this PR changes `createNewBlock()` from a method that returns quickly to one that can block for minutes, we rely on #34568 to fix a bug in our `.capnp` definition, adding the missing `context` to `createNewBlock` (and `checkBlock`). The second commit then adds an `interrupt()` method so that clients can cleanly disconnect. --- ## Rationale The cooldown argument is optional, and not used by internal non-IPC code, for two reasons: 1. The mechanism wreaks havoc on the functional test suite, which would require very careful mock time handling to work around. But that's pointless, because only IPC clients need it. 2. It needs to be optional for IPC clients too, because in some situations, like a signet with only one miner, waiting for IBD can mean being stuck forever. The reason it's only applied to `createNewBlock()` is that this is the first method called by clients; `waitNext()` is a method on the interface returned by `createNewBlock()`, at which point the cooldown is done. After IBD, we wait N seconds if the header is N blocks ahead of the tip, with a minimum of 3 and a maximum of 20 seconds. The minimum waiting time is short enough that it shouldn't be annoying or confusing for someone manually starting up a client. While the maximum should be harmless if it happens spuriously (which it shouldn't). If the minimum wait is too short, clients get a burst of templates, as observed in the original issue. We can't entirely rule this out without a lot of additional complexity (like scanning our own log file for heuristics). This PR should make it a lot less likely, and thanks to the IBD wait also limit it to one day worth of blocks (`-maxtipage`). Some test runs on an M4 MacBook Pro, where I had a node catch up on the last few days worth of blocks: <img width="872" height="972" alt="Schermafbeelding 2026-02-04 om 18 21 17" src="https://github.com/user-attachments/assets/7902a0f2-0e0b-4604-9688-cec2da073261" /> As the chart shows, sometimes it takes longer than 3 seconds. But it turns out that in all those cases there were quite a few headers ahead of the tip. It also demonstrates that it's important to first wait for IBD, because it's less likely a random tip update takes longer than 20 seconds. - modified sv2-apps: https://github.com/Sjors/sv2-apps/tree/2026/02/cooldown - test script: https://gist.github.com/Sjors/feb6122c97acc2b9e6d66b168614609c#file-run_mainnet_pool_loop-zsh - chart script: https://gist.github.com/Sjors/feb6122c97acc2b9e6d66b168614609c#file-tip_interval_charts-py ACKs for top commit: ryanofsky: Code review ACK fcaec2544b32226fd5357a88506fe080058d25bc. Only changes since last review were removing two cooldown arguments from the mining IPC test to simplify it enirox001: ACK fcaec2544b Tree-SHA512: 08b75470f7c5c80a583a2fdb918fad145e7d5377309e5c599f67fc0d0e3139d09881067ba50c74114f117e69da17ee50666838259491691c031b1feaf050853f
Bitcoin Core integration/staging tree
For an immediately usable, binary version of the Bitcoin Core software, see https://bitcoincore.org/en/download/.
What is Bitcoin Core?
Bitcoin Core connects to the Bitcoin peer-to-peer network to download and fully validate blocks and transactions. It also includes a wallet and graphical user interface, which can be optionally built.
Further information about Bitcoin Core is available in the doc folder.
License
Bitcoin Core is released under the terms of the MIT license. See COPYING for more information or see https://opensource.org/license/MIT.
Development Process
The master branch is regularly built (see doc/build-*.md for instructions) and tested, but it is not guaranteed to be
completely stable. Tags are created
regularly from release branches to indicate new official, stable release versions of Bitcoin Core.
The https://github.com/bitcoin-core/gui repository is used exclusively for the development of the GUI. Its master branch is identical in all monotree repositories. Release branches and tags do not exist, so please do not fork that repository unless it is for development reasons.
The contribution workflow is described in CONTRIBUTING.md and useful hints for developers can be found in doc/developer-notes.md.
Testing
Testing and code review is the bottleneck for development; we get more pull requests than we can review and test on short notice. Please be patient and help out by testing other people's pull requests, and remember this is a security-critical project where any mistake might cost people lots of money.
Automated Testing
Developers are strongly encouraged to write unit tests for new code, and to
submit new unit tests for old code. Unit tests can be compiled and run
(assuming they weren't disabled during the generation of the build system) with: ctest. Further details on running
and extending unit tests can be found in /src/test/README.md.
There are also regression and integration tests, written
in Python.
These tests can be run (if the test dependencies are installed) with: build/test/functional/test_runner.py
(assuming build is your build directory).
The CI (Continuous Integration) systems make sure that every pull request is tested on Windows, Linux, and macOS. The CI must pass on all commits before merge to avoid unrelated CI failures on new pull requests.
Manual Quality Assurance (QA) Testing
Changes should be tested by somebody other than the developer who wrote the code. This is especially important for large or high-risk changes. It is useful to add a test plan to the pull request description if testing the changes is not straightforward.
Translations
Changes to translations as well as new translations can be submitted to Bitcoin Core's Transifex page.
Translations are periodically pulled from Transifex and merged into the git repository. See the translation process for details on how this works.
Important: We do not accept translation changes as GitHub pull requests because the next pull from Transifex would automatically overwrite them again.