CGAL
STL_Extension: Add bisect_failures debugging utility
Summary
This PR adds a new debugging utility bisect_failures to the STL_Extension package. This function helps identify minimal failing test cases from complex input data by using a bisection-like approach.
Small feature: bisect failures debugging utility
Features
- Multiple failure type support: Handles CGAL exceptions, std::exceptions, and exit codes
- Automatic granularity adjustment: Starts with ratio=0.5, automatically halves when no fault is found
-
Debug output: Saves intermediate states (
current,bad,error,final_bad) - Template-based design: Works with any copyable/assignable data type
Testing
Added comprehensive test suite (test_bisect_failures.cpp) with 14 tests:
- ✅ Edge cases (empty data, no failures)
- ✅ Single element failures (CGAL exception, std::exception, exit code)
- ✅ Pair combinations (all 2-element permutations)
- ✅ Triple combinations (all 3 failure types together)
All tests pass in both Debug and Release configurations.
Use Case
This utility is particularly useful for:
- Debugging complex geometric algorithms with large input datasets
- Finding minimal reproducible test cases from failing inputs
- Isolating problematic elements in mesh processing, triangulation, etc.
Example Usage
auto get_size = [](const Mesh& m) { return m.number_of_faces(); };
auto simplify = [](Mesh& m, std::size_t start, std::size_t end) -> bool {
// Remove faces from start to end
for(std::size_t i = start; i < end && i < m.number_of_faces(); ++i) {
m.remove_face(start);
}
return true;
};
auto run = [](const Mesh& m) -> int { return algorithm(m); };
auto save = [](const Mesh& m, const std::string& prefix) {
std::ofstream out(prefix + ".off");
out << m;
};
int result = bisect_failures(mesh, get_size, simplify, run, save);
Files Changed
-
STL_Extension/include/CGAL/bisect_failures.h(new) - Main utility header -
STL_Extension/test/STL_Extension/test_bisect_failures.cpp(new) - Test suite -
STL_Extension/test/STL_Extension/CMakeLists.txt(modified) - Added test
Checklist
- [x] Code compiles without errors (Debug and Release)
- [x] All tests pass
- [x] Comprehensive documentation with Doxygen comments
- [x] Example usage in documentation
- [x] Follows CGAL coding style conventions
- [x] Deal with false positive in the testsuite
The documentation is built. It will be available, after a few minutes, here: https://cgal.github.io/9118/v1/Manual/index.html
![github-actions[bot] avatar](https://avatars.githubusercontent.com/in/15368?v=4 "Published by a pub.dev verified publisher"){kind=small}
The documentation is built. It will be available, after a few minutes, here: https://cgal.github.io/9118/v1/Manual/index.html
The documentation is built. It will be available, after a few minutes, here: https://cgal.github.io/9118/v1/Manual/index.html
The documentation is built. It will be available, after a few minutes, here: https://cgal.github.io/9118/v1/Manual/index.html
Fails in 50% of today's testsuites https://cgal.geometryfactory.com/CGAL/testsuite/summary-6.2-Ic-40.html?package=STL_Extension_Examples
