I have a complex project that used to compile without any problems that i could not solve before I bought a new iMac (the latest, M4), which came with macOS Sequoia. I've ben able to compile the whole project since 1998, which has evolved into an AppKit Mac app written almost completely in Swift. I am also able to compile this project on Xcode 16.1 on MacOS Sonoma. However, since I upgraded to MacOS Sequoia, I am stumped with lots of errors that I don't know how to fix. Many of them are related to new build system, which works fine in smaller projects I have written, but it completely breaks when I use this more complex project. I've been unable to create a focused project so I can file a DTS incident, because when I try to recreate it in a new, more focused project, the problem goes away. I tried to transfer the code to a freshly created project, and I was able to make it build again without errors, but then this new project just creates empty bundles without any resources and executables in them. In almost 25 years of experience in coding, I've never encountered such huge problems with just a MacOS upgrade. I would like to have some guidance on how to proceed. Here is an example of the errors I'm getting:
error: unable to write file '/SchIS64.build/Objects-normal/arm64/SchIS64.LinkFileList': fopen(/SchIS64.build/Objects-normal/arm64/SchIS64.LinkFileList, wb): No such file or directory (2) (in target 'SchIS64' from project 'Scheduler (Cocoa)')
WriteAuxiliaryFile /SchIS64.build/unextended-module.modulemap (in target 'SchIS64' from project 'Scheduler (Cocoa)')
cd /Users/admin/Documents/Development/Scheduler/Scheduler
write-file /SchIS64.build/unextended-module.modulemap
WriteAuxiliaryFile /SchIS64.build/unextended-module-overlay.yaml (in target 'SchIS64' from project 'Scheduler (Cocoa)')
cd /Users/admin/Documents/Development/Scheduler/Scheduler
write-file /SchIS64.build/unextended-module-overlay.yaml
WriteAuxiliaryFile /SchIS64.build/SchIS64.hmap (in target 'SchIS64' from project 'Scheduler (Cocoa)')
cd /Users/admin/Documents/Development/Scheduler/Scheduler
write-file /SchIS64.build/SchIS64.hmap