Lőrinc b80d0bdee4 test: avoid stack overflow in FindChallenges via manual iteration
The original recursive `FindChallenges` explores the Miniscript node tree using depth-first search. Specifically, it performs a pre-order traversal (processing the node's data, then recursively visiting children from left-to-right). This recursion uses the call stack, which can lead to stack overflows on platforms with limited stack space, particularly noticeable in Windows debug builds.

This change replaces the recursive implementation with an iterative version using an explicit stack. The iterative version also performs a depth-first search and processes the node's data before exploring children (preserving pre-order characteristics), although the children are explored in right-to-left order due to the LIFO nature of the explicit stack.
Critically, both versions collect challenges into a `std::set`, which automatically deduplicates and sorts elements. This ensures that not only the final result, but the actual state of the set at any equivalent point in traversal remains identical, despite the difference in insertion order.

This iterative approach is an alternative to increasing the default stack size (as proposed in #32349) and directly addresses the stack overflow issue reported in #32341 by avoiding deep recursion.

The change is done in two commits:
* add a new iterative `FindChallenges` method and rename the old method to `*_recursive` (to simplify removal in the next commit), asserting that its result matches the original;
* Remove the original recursive implementation.

This approach avoids needing to suppress `misc-no-recursion` warnings and provides a portable, low-risk fix.

Using a `std::set` is necessary for deduplication, matching the original function's behavior. An experiment using an `std::vector` showed duplicate challenges being added, confirming the need for the set:
Example failure with vector:
  Recursive (set):
    (6, 9070746)
    (6, 19532513)
    (6, 3343376967)
  Iterative (vector attempt):
    (6, 19532513)
    (6, 9070746)
    (6, 3343376967)
    (6, 9070746) // Duplicate

Co-authored-by: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
2025-04-28 15:46:59 +02:00
2025-04-22 12:49:53 +02:00
2025-02-06 09:38:49 +00:00
2025-04-17 10:33:01 +01:00
2025-02-18 20:46:30 +01:00
2023-06-01 23:35:10 +05:30
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Bitcoin Core integration/staging tree

https://bitcoincore.org

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/licenses/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 built for Windows, Linux, and macOS, and that unit/sanity tests are run automatically.

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.

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