Xcode 12 Build failed, error: circular reference

Question

Created Sep ’20

Replies 7

Boosts 0

Views 9.7k

Participants 8

Our project compiles and runs fine on Xcode 11.

However, when I compile with Xcode 12, it tells me <unkown>0: error: circular reference

The specific information is as follows:
<unknown>:0: error: merge-module command failed with exit code 1 (use -v to see invocation)

and

<unknown>:0: error: circular reference Command MergeSwiftModule failed with a nonzero exit code

Please see my attachments for specific errors.

Other than that, I can't get any more error messages.

Xcode 12 build failed logs

Answered by ForumsContributor in

Boost

Answer 1

jlilest OP

Sep ’20

Just to suggest the obvious, have you cleaned the build folder?

I get that sort of error on a client project when running UI tests after the second time.

0

Answer 2

wkKevin OP

Sep ’20

@jlilest

Yes, we cleaned up the build directory DerivedData, including using Xcode's Clean Build (Command + Shift + K, Command + Option + Shift + K), and we still get this error.

This error is only available in Xcode 12 Release up to and including Beta.

0

Answer 3

DoxxerApple OP

Sep ’20

Faced same error on stage MergeSwiftModule

Did you try change the project setting SWIFT_COMPILATION_MODE from Incremental to the Whole Module?

5

Answer 4

wkKevin OP

Sep ’20

@DoxxerApple

Yeah, this worked for me.
But I would like to know why, after all, the whole module compilation is too slow.

1

Answer 5

wkKevin OP

Sep ’20

Accepted Answer

I solved the problem, I think it was an xcode12 bug.

Old Codes:

Code Block extension UIWindow.Level {
	private static var statusBarRawValue: RawValue { UIWindow.Level.statusBar.rawValue }
}

New Codes:

Code Block extension UIWindow.Level {
	private static var statusBarRawValue: CGFloat { UIWindow.Level.statusBar.rawValue }
}

1

Answer 6

setoelkahfi OP

Nov ’20

Hi @wkKevin,

I think this error is logical. I ran the same issue after upgrading my XCode to XCode 12.

In my case, I reference the same type to the the type that is using it:

Code Block swift
class OnboardingStep: NavigationFlowStep<StepInput.OnboardingWelcome> {
    struct InitialData {
        var onboardingList: ListTitles
        var featuredTitle: Product
        var welcomeScreenTitle: Product
    }
	....

and in OnboardingStepInput.swift I have this InitialData reference there:

Code Block languagestruct StepInput {
	...
	typealias OnboardingWelcome = (
    	availableSteps: [OnboardingScreen],
   		initialData: OnboardingStep.InitialData
  	)
	...

and in your code here, it has similar pattern:

Code Block swiftextension UIWindow.Level {
	private static var statusBarRawValue: RawValue { UIWindow.Level.statusBar.rawValue }
}

it references itself. Maybe not the best explanation that I can come up with, but I think you've got my point.

1

Answer 7

dervisyilmaz OP

Sep ’22

my project was successfully builded and deployed the device, but when I want to archive to project for AppStore, I faced same error. including using Xcode's Clean Build (Command + Shift + K ), Updated dependencies and change SWIFT_COMPILATION_MODE from Incremental to the Whole Module, the project was archived successfully using Xcode 13.3, but was not archived using Xcode 14.0. Please help me

1