Migration to Swift 4 from Swift 3.2 giving "failed to import bridging header " error

Question

As apple has released Xcode 9 beta version with Swift 4.0 support. I have been trying to upgrade my code to Swift 4.0 from Swift 3.2. But it keeps giving me failed to import bridging header error whereas my project build successfully.

Xcode error detail:

Convert to Current Swift Syntax Failed

Please ensure that all selected targets build successfully with the currently configured Swift version before attempting a migration.

Has anybody faced the similar error while upgrading code base to swift 4.

I deleted the `NAME.xcworkspace ` and regenerate using 'pod install' then it works. — JZAU, Aug 30 '17 at 03:12

score 9 · Answer 1 · edited Jul 28 '17 at 11:20

9

I had the similar problem in one of my projects and how I solved this is next:

I figured out that CocoaPods are the problem.

I removed CocoaPods from my project (if you don't know how to do that check this How to remove CocoaPods from a project?)
Don't forget If you have unit & ui tests you have to repeat 4th step from the link above on them as well.
Upgrade your code base to Swift 4
Install pods again and you are done.

Hope it helps :)

edited Jul 28 '17 at 11:20

swiftBoy

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answered Jul 26 '17 at 16:12

Tino Krželj

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I have this problem even though I don't use CocoaPods – Kirill Titov Sep 14 '17 at 17:52
Make sure you store your podfile at one place before removing it. – Chetan Rajagiri Feb 25 '19 at 12:17
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"pod deintegrate" does the job! – chris Nov 07 '19 at 16:23

score 4 · Answer 2 · answered Jun 18 '19 at 07:45

4

for us what worked was to remove the UnitTest and UITests

Tap on your project and then "Right Click" -> Remove the two dependencies

Hope it helps

answered Jun 18 '19 at 07:45

tsik

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score 1 · Answer 3 · answered Sep 19 '17 at 09:45

For me, my migration from 3.2 to 4.0 failed, then I always get this error message when I try to Edit > Convert > To Current Swift Syntax...

My Fix is simple, set the project setting's swift version from 4.0 back to 3.2 or whichever version you were using.

This is because although the first migration has failed, Xcode has changed the swift version to 4.0 in your project settings.

score 0 · Answer 4 · answered Sep 18 '17 at 02:09

0

Make sure that all the targets compile including the tests. delete NAME.xcworkspace once Cocoapods are removed from the project

This solved it for me.

answered Sep 18 '17 at 02:09

Abdullah Khan

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score 0 · Answer 5 · answered Oct 18 '17 at 08:29

Probably at least one of the objective c classes you put in your bridging header file is not compiling - comment out all your entries in the bridging header file, then compile - it should be able to import the bridging header now, but of course generate lots of errors because of classes not found. Now uncomment the lines one by one to find out which ones are causing the import to fail, and then fix those files.

score 0 · Answer 6 · answered Jan 05 '19 at 07:01

After changing the Swift Language Version in my Project's build settings and in all the targets I had to alter this function declaration in AppDelegate.swift to:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { // Override point for customization after application launch. return true }

score 0 · Answer 7 · answered Jul 10 '20 at 17:17

All of my code is in Swift 5, except for one of my Pods which hasn't been updated in a few years. That pod uses Swift 4.

This error happened for me when I added a new Swift5 pod.

So, All I needed to do was:

Change Affected Pod's Swift version to match the rest of the project

Clean project

Migration to Swift 4 from Swift 3.2 giving "failed to import bridging header " error

7 Answers7