emits an invalid Swift module interface, due to a public type (IOSSecuritySuite.IOSSecuritySuite class) has the same name as a module #110
Description
Due to the invalid Swift module interface, a IOSSecuritySuite binary outputted with an older Swift toolchain will not be considered compatible newer Swift toolchains.
Example:
- I previously built IOSSecuritySuite xcframework binary with an older Xcode 14.x
- Attempts to build a project, that links against that xcframework with Xcode 15.x will result in build errors.
- See bottom of this message for an example of the Xcode 15 build error.
Analysis:
- Root cause is the public IOSSecuritySuite class which has the same name as the module.
- The official Swift github issue tracker has already documented this as a known issue:
Solution:
- Update build setting BUILD_LIBRARY_FOR_DISTRIBUTION to YES
- This will enable Swift library evolution and Swift module stability. For details see: https://www.swift.org/blog/library-evolution/
- Update build setting OTHER_SWIFT_FLAGS with value -verify-emitted-module-interface
- this will ensure that future Swift Module Interface issues result in a compile time error.
- Change the module to IOSSecuritySuiteLib, instead of IOSSecuritySuite
- This will break builds, due to any previous Import statement using the now incorrect Module name.
- I have already verified that this works.
- i.e. outputting a binary with Xcode 13.x/14.x is now compatible with Xcode 15.x
- I will submit a Pull Request with these changes to resolve this issue.
Example of the Xcode 15.x build error:
Failed to build module 'IOSSecuritySuite'; this SDK is not supported by the compiler (the SDK is built with 'Apple Swift version 5.6.1 (swiftlang-5.6.0.323.66 clang-1316.0.20.12)', while this compiler is 'Apple Swift version 5.9.2 (swiftlang-5.9.2.2.56 clang-1500.1.0.2.5)'). Please select a toolchain which matches the SDK.