fix: accessing Availability.h macros in Swift (Xcode 26 support)

[liamnichols]

Issue #

#4003

Description

Starting in Xcode 26, the Availability.h/AvailabilityInternal.h headers that contained the __IPHONE_OS_VERSION_MIN_REQUIRED and __MAC_OS_X_VERSION_MIN_REQUIRED preprocessor macros are no longer implicitly exposed to Swift code via the os_availability/os_availability_internal modules which has prevented the Amplify SDK from compiling.

I saw that the xcode-26 branch just commented out the problematic code as a workaround, but I wanted to propose a more suitable fix that involved explicitly exposing the macro values to the AWSCognitoAuthPlugin target via a new AmplifyAvailability system library target.

The new target defines a module map that exposes the AmplifyAvailability.h header and within this header, we just redefine the Availability.h preprocessor macros via getIOSVersionMinRequired() and getMACOSXVersionMinRequired(). These new static symbols are now exposed to the Swift code and can be used instead to provide support both in Xcode 26 and older versions.

General Checklist

• Added new tests to cover change, if needed
• Build succeeds with all target using Swift Package Manager
• All unit tests pass
• All integration tests pass
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• New or updated tests include Given When Then inline code documentation and are named accordingly testThing_condition_expectation()
• If breaking change, documentation/changelog update with migration instructions

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[harish-suthar]

@liamnichols This looks a prominent fix any ideas by when can we see this merged and released?

CC: @harsh62

[harsh62]

@harish-suthar Thanks for tagging me.

@liamnichols Thanks for you contribution. The change on a high level looks good. I've approved and ran the workflows to check the health of the PR.

I will work with my team to get feedback.

[harsh62]

@liamnichols @harish-suthar This needs to be build on the minimum version of Xcode supported by Amplify which is Xcode 15. At the moment its failing with:

Error: cannot find 'getIOSVersionMinRequired' in scope

[liamnichols]

@liamnichols @harish-suthar This needs to be build on the minimum version of Xcode supported by Amplify which is Xcode 15. At the moment its failing with:

Error: cannot find 'getIOSVersionMinRequired' in scope

Hi @harsh62, thanks for pointing this out.. I don't have access to Xcode 15 locally so I hadn't realised this 🙇 I've made some changes to use a regular .target instead of .systemLibrary that defines a small .c file rather than using inline functions, I think this should work better with Xcode 15 but I still haven't tested it myself.

If you could re-run CI that would be appreciated 🙏

[harsh62]

LGTM

[liamnichols]

Thanks for merging this @harsh62! Would it be possible if you could share timelines for releasing updates to amplify-swift and amplify-ui-swift-liveness that contain this patch?

No worries if it won't be for a while, I just need to know if it is worth me creating some forks and using them in the meantime or not 🙂

[harsh62]

I am gonna try to release this week, with a couple of other fixes in the pipeline. At most it could slip into next week.