On macOS 14 Sonoma there is a regression in Swift 5.9 which causes Swift scripts that import Cocoa frameworks to fail. This issue was first reported by @rdj. I discovered it myself shortly after. There is a ticket open at #68785 on the main Swift repo on GitHub to track the issue.
Considering the following Swift script:
#!/usr/bin/swift
import AppKit
import Foundation
NSPasteboard.general.clearContents()
NSPasteboard.general.setString("Hello, Swift!", forType: .string)
print("Hello, Swift!")
You can run directly from the command line:
$ ./hello.swift
Hello, Swift!
On macOS 13 and earlier, this works. Unfortunately, on macOS 14 it now fails with an error: “JIT session error: Symbols not found”.
JIT session error: Symbols not found: [ _OBJC_CLASS_$_NSPasteboard, _NSPasteboardTypeString ]
Failed to materialize symbols:
[...]
The current workaround (also posted by @rdj) is to update the shebang, #!/usr/bin/swift, by replacing it with the following:
#!/usr/bin/env DYLD_FRAMEWORK_PATH=/System/Library/Frameworks /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift
Note: you must also have Xcode installed for this to work.
I’ve verified that this does indeed fix the problem!