Firebase Analytics has not been created. ld: warning: Some object files have incompatible Objective-C category definitions - objective-c

Question

ld: warning: Some object files have incompatible Objective-C category definitions. Some category metadata may be lost. All files containing Objective-C categories should be built using the same compiler.
This warning above appeared when I installed the Firebase/Core through cocopods. And I believe it cause an error, because my project can't read the FIRApp.configure() at App deleagate in my project. I am sure I download the GoogleService-Infor.plist and put it in the right place in project, because I done it on my another project before (work properly), my another project didn't have the Objective-C categories warning.
Can anyone help me out?
The process that I've done:
Add pod 'Firebase/Core' in the project podfile, close the xcode.
Open terminal, go to the target project folder, execute pod install.
Appear a warning on terminal (Solution: just put the $(inherited) in the build setting of ALWAYS_..., then problem solve)
[!] The xxxxxx-ebooking [Debug] target overrides the ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES build setting defined in `Pods/Target Support Files/Pods-xxxxxx-ebooking/Pods-xxxxx-ebooking.debug.xcconfig'. This can lead to problems with the CocoaPods installation:
Use the $(inherited) flag, or
Remove the build settings from the target.
Appear a warning on xcode (This issues are simple, just commit the new files then warning will gone):
file:///Users/yyyyyy/Projects/xxxxxx_projects/xxxxxx-ebooking/Pods/Target%20Support%20Files/Pods-xxxxxx-ebooking/Pods-xxxxxx-ebooking.debug.xcconfig: warning: Missing file: /Users/yyyyyy/Projects/xxxxxx_projects/xxxxxx-ebooking/Pods/Target Support Files/Pods-xxxxxx-ebooking/Pods-xxxxxx-ebooking.debug.xcconfig is missing from working copy
Ignore the issues process of 3, 4, because it are easy to solve. Because the most wired warning is :
ld: warning: Some object files have incompatible Objective-C category definitions. Some category metadata may be lost. All files containing Objective-C categories should be built using the same compiler.
Firebase Analytics has not been created. Please, configure Firebase by calling [FIRApp configure]
I did put the FIRApp.configure() in my project. But when I call FA event on some view did load, it will show this warning. I believe it is because the Objective-C warning.

Answer 1

see if using #nonobjc on your static variable resolve the issue

Answer 2

Finally I solved all bugs, thanks my friend help me to debug and stack overflow community. Here is the solution:
In the beginning I thought this warning "ld: warning: Some object files have incompatible Objective-C category definitions" caused the fail of executing the FIRApp.configure(). But it end out it are two different errors!
First issue, The FIRApp.configure() issues is because my project has error migration when swift 2.2 to 3.0. The xcode suggested me to change the old 2.2 syntax to be private method in AppDelegate:
private func application(application: UIApplication, willFinishLaunchingWithOptions launchOptions: [NSObject : AnyObject]?) -> Bool {
// This method is your app’s first chance to execute code at launch time.
FIRApp.configure()
return true
}
The FIRApp.configure() will never execute because it is not AppDelegate's method. So, changed back to correct syntax will solve the issues:
func application(_ application: UIApplication, willFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {
print("Fire! willFinishLaunchingWithOptions")
return true
}
Second issue, if using the below demo syntax and your project has objective-C in third party plug-in or your code, it will cause the warning "Some object files have incompatible Objective-C...". Maybe, because syntax is old for swift 3.0 so it appear this warning.
class var applicationBuildNumber: String {
if let build = Bundle.main.infoDictionary?["CFBundleVersion"] as? String {
return build
}
return "Build Number Not Available"
}
If you using class function, then this warning will disappear:
class func appLocalBuild() -> String {
return Bundle.main.object(forInfoDictionaryKey: kCFBundleVersionKey as String) as! String
}