is xcode 26 already supported?

[yveshanoulle]

I had slather configured before, after upgrading to xcode 26 I can't seem t get it working again

[jarrodlombardo-EventBase]

Yes it works with XCode 26. Slather depends on the coverage data generated by clang instrumentation in the XCode build though, so you must be sure that all of your upstream dependencies are also built with XCode 26 due to https://developer.apple.com/forums/thread/770289

[mikehouse]

Xcode 16.3, 16.4 and 26.0 does not work as Coverage.profdata is not generated. Xcode 26.1 got it fixed and slather works again.

[jarrodlombardo-EventBase]

@mikehouse Do you know if Apple changed how XCode 26.1 depends on CLang or did your upstream dependencies happen to update to a matching version of CLang coincidentally with you adopting XCode 26.1?

[jarrodlombardo-EventBase]

Also, all versions of XCode are supported and work with Slather, but you are limited to matching versions of CLang as described here.

[mikehouse]

Do you know if Apple changed how XCode 26.1 depends on CLang

Seems Apple has changed something because it started to work)
I changed nothing to my project at all.

1. Several months ago my project had binary dependencies (Carthage) being built with Xcode 15.2 (in distribution mode enabled)

• Xcode 16.2 was generating Coverage.profdata
• Xcode 16.3 didn't generate Coverage.profdata
• Xcode 16.4 didn't generate Coverage.profdata
• Xcode 26.0 beta didn't generate Coverage.profdata

2. Recently I have rebuilt binary dependencies with Xcode 16.4

• Xcode 16.4 started to generate Coverage.profdata
• Xcode 26.0 beta as I remember didn't generate Coverage.profdata
• Xcode 26.1 as I remember is generating Coverage.profdata

Tomorrow I will check one more time with Xcode 26.0.1 and Xcode 26.1

*updated

[jarrodlombardo-EventBase]

1. is expected in all of those combinations because XCode 16.0 updated LLVM and all upstreams must be built with XCode 16.0-16.2 to be compatible with XCode 16.0-16.2.
2. is partly expected and partly surprising: XCode 16.3 updated LLVM and all upstreams must be built with XCode 16.3-16.4 to be for sure be compatible with XCode 16.3-16.4. XCode 26.0 had a patch update of LLVM that included a minor update of Clang that should be compatible with Xcode 16.3+, but I don't know if it actually is. XCode 26.1 had another minor upgrade of CLang that should be compatible with XCode 16.3+, but again I don't know if it actually is.

My data about which versions should be compatible with each other comes from:

• https://gist.github.com/yamaya/2924292
• https://en.wikipedia.org/wiki/Xcode#Toolchain_versions

[mikehouse]

I've updated my previous answer. Thank you.

[mikehouse]

Yes, you are right 🙂 After I built static libraries with Xcode 16.4 in distribution mode the Coverage.profdata file started to appear again for Xcode 16.4 and Xcode 26+. Thank you. Finally I figured it out why it didn't work when binaries are built with Xcode 15.2 and tests run on Xcode 16.3+.

[yveshanoulle]

Thanks I now have it working also in 26.1