Flutter iOS build failure error with Multiple commands after the Xcode upgrade

Question

Flutter iOS build fails after upgrading to Xcode 10.0 version in mac.

Nagendras-MacBook-Pro:uaenumber nagendra$ flutter run
Launching lib/main.dart on iPhone X in debug mode...
Starting Xcode build...
Xcode build done.                                            1.4s
Failed to build iOS app
Error output from Xcode build:
↳
    ** BUILD FAILED **

Xcode's output:
↳
    error: Multiple commands produce '/Users/dev/Documents/projects/Personal/uaenumber/build/ios/Debug-iphonesimulator/Runner.app/Frameworks/Flutter.framework':
    1) Target 'Runner' has copy command from '/Users/dev/Documents/projects/Personal/uaenumber/ios/Flutter/Flutter.framework' to '/Users/dev/Documents/projects/Personal/uaenumber/build/ios/Debug-iphonesimulator/Runner.app/Frameworks/Flutter.framework'
    2) That command depends on command in Target 'Runner': script phase “[CP] Embed Pods Frameworks”
    warning: The use of Swift 3 @objc inference in Swift 4 mode is deprecated. Please address deprecated @objc inference warnings, test your code with “Use of deprecated Swift 3 @objcinference” logging enabled, and then disable inference by changing the "Swift 3 @objc Inference" build setting to "Default" for the "Runner" target. (in target 'Runner')
    warning: ignoring duplicated output file: '/Users/nagendra/Documents/projects/Personal/uaedialer/build/ios/Debug-iphonesimulator/Runner.app/Frameworks/Flutter.framework' (in target 'Runner')
    note: Using new build systemnote: Planning buildnote: Constructing build description
Could not build the application for the simulator.
Error launching application on iPhone X.

Xcode Version - 10.0 (10A255)

I tried to recreate the project and copied all the source files to the new project folder but it does not resolve the issue.

Answer 1

This solution worked for me.

1. Open ios/Runner.xcworkspace Select the Runner project in the project navigator sidebar.
2. In the main view, select the Runner target, then select the Build Phases tab.
3. Expand the Embed Frameworks phase and select Flutter.framework from the embedded frameworks list.
4. Click - to remove Flutter.framework from the list (be sure to keep App.framework).

Answer 2

It's a known issue. Here is the explanation and some workarounds: https://github.com/flutter/flutter/issues/20685#issuecomment-421511890

Affected projects

This issue affects all Flutter projects built using Xcode 10 that have a dependency on CocoaPods -- typically this means those that rely on plugins. Workarounds

There are two workarounds:

• Option 1: Use the legacy build system . As noted by @gi097, open ios/Runner.xcworkspace, and change the build system to Legacy Build System.
• Option 2: Use the new Xcode 10 build system. Open ios/Runner.xcworkspace Select the Runner project in the project navigator sidebar. In the main view, select the Runner target, then select the Build Phases tab. Expand the Embed Frameworks phase and select Flutter.framework from the embedded frameworks list. Click - to remove Flutter.framework from the list (be sure to keep App.framework).

Root cause

When plugins are in use, there are two competing build actions that copy Flutter.framework into the build application Frameworks directory:

The Embed Frameworks build phase for the Runner project

The [CP] Embed Pods Frameworks build phase that pod install creates in the project.

Item (1) is there to ensure the framework is copied into the built app in the case where there are no plugins (and therefore no CocoaPods integration in the Xcode project). Item (2) is there because Flutter's podspec declares Flutter.framework as a vended_framework, and CocoaPods automatically adds a copy step for each such vended_framework in the transitive closure of CocoaPods dependencies.

Answer 3

If you have tried everything and still cannot build the Archive successfully, then you look like my case.

It took me 3 business days to fix this. My problem happened after adding the Notification Services target to the project. But it looks like it will apply to many other cases as well:

The problem is caused by the library inside 2 target multiple commands produce. In my case, for example, in the project target and notification extension target, both GoogleUtilities had this causing them to conflict or duplicated the commands produce. The solution is to make that dependency explicit, at the top level. The pod file will look like this:

platform :ios, '10.0'
use_frameworks!
inhibit_all_warnings!

pod 'GoogleUtilities' // Add this line is very important.

target 'MyProject' do
  pod 'Firebase/Analytics'
  pod 'Firebase/Crashlytics'
  pod 'Firebase/Messaging'
# Other pods
end

target 'NotificationService' do
  pod 'Firebase/Messaging'
end

After run:

pod deintegrate
pod install 

Answer 4

This issue was fixed by opening the Runner workspace project in Xcode 10. Then navigate to File, Workspace Settings and change the build system to Legacy Build System.

Answer 5

Edit: The latest stable version of Flutter will migrate your Xcode project to the new build system (step one below) and avoid the multiple embedded frameworks warning altogether. If it doesn't, follow the instructions at https://flutter.dev/docs/development/ios-project-migration. You no longer need to edit your Podfile (step two below).

See https://github.com/flutter/flutter/issues/20685#issuecomment-622126064

Previous answer

1. Open ios/Runner.xcworkspace in Xcode. File > Workspace Settings... > Build System, change dropdown to New Build System (Default)
2. In your Podfile, add the line

install! 'cocoapods', :disable_input_output_paths => true

3. In your Flutter app, build again to trigger a pod install, which will automatically clean up the build phase

flutter build ios

See: https://github.com/flutter/flutter/issues/20685#issuecomment-509731873 https://github.com/flutter/flutter/issues/20685#issuecomment-510162863

Warning: Do not revert to the Xcode deprecated legacy build system to fix this issue as suggested in the other answers.