This is probably a beginner's mistake, but I can't find anything about this error anywhere, and it's completely reproducible, even on GitHub Runners and with a fresh Xcode project.
The error doesn't seem to be caused by the Swift package used, Defaults, but by xcodebuild.
macOS Sequoia 15.2 (24C101)
Xcode Version 16.2 (16C5032a)
Defaults Version 9.0.0
When following Defaults' installation instructions, building and archiving from Xcode still works fine, but building with xcodebuild always fails with this error:
Copy /Users/user/DefaultsTest/build/Release/DefaultsTest.app/Contents/Resources/Defaults_Defaults.bundle /Users/user/DefaultsTest/build/Release/Defaults_Defaults.bundle (in target 'DefaultsTest' from project 'DefaultsTest')
cd /Users/user/DefaultsTest
builtin-copy -exclude .DS_Store -exclude CVS -exclude .svn -exclude .git -exclude .hg -resolve-src-symlinks /Users/user/DefaultsTest/build/Release/Defaults_Defaults.bundle /Users/user/DefaultsTest/build/Release/DefaultsTest.app/Contents/Resources
error: /Users/user/DefaultsTest/build/Release/Defaults_Defaults.bundle: No such file or directory (in target 'DefaultsTest' from project 'DefaultsTest')
I made a fresh, reproducible Xcode project here:
https://github.com/F1248/DefaultsTest
And a failing GitHub Action here:
https://github.com/F1248/DefaultsTest/actions/runs/12303972248/job/34340347771
Any help would be greatly appreciated.