I saw the similar issue in stackoverflow, and add --use-libraries after pod spec lint. It just says
[!] Pods written in Swift can only be integrated as frameworks; this feature is still in beta. Adduse_frameworks!to your Podfile or target to opt into using it. It very strange.
My question is how to create a framework which is written in objective-c and swift, and create a private cocoapods repository. I cannot create a correct .podspec because I use objective-c bridging header in framework, and pod spec lint always tell me error: include of non-modular header inside framework module. This makes me gonna be crazy...
I also post this issue in detail in github:
https://github.com/CocoaPods/CocoaPods/issues/3666
If anyone knows how to fix it, I'll be very appreciate for you. Thanks a lot!