We have been seeing a dyld loader crash when trying out the new Previews engine in Xcode 16 beta 3.
Feedback filed with reproducer + diagnostics: https://feedbackassistant.apple.com/feedback/14323960
Investigation:
- Running nm -a on the debug dylib reveals duplicate SO entries pointing to SomeStatic.swift. One entry originates from the LibAStatic module, while the other comes from the LibBStatic module.
- Local workaround - 1 Providing unique file names resolves the issue. However, these files are in different modules, so ideally, this shouldn't be necessary. Our codebase is extensive, and many code-generated modules have the same file names. Therefore, renaming files to ensure uniqueness is not a simple solution for us due to various complexities.
- Local workaround - 2 Making these dependencies dylibs instead of static libraries also resolves the issue. However, we can't pursue this direction because a significant portion of our pre-build setup, foundations, and vendor linkages are statically linked.
Note: The same flow works with "Legacy Preview Engine in Xcode 16/15" but dynamic replacement has other issues, which we are super happy that the new engine doesn't make use of.
This issue is currently a blocker for us in trying out the new Previews in our project, it would be highly beneficial if this problem could be resolved soon.
