Xcode build fails: “Multiple commands produce …/Settings.bundle” when using --output-type settings-bundle

[benjaminkech]

Description

When enabling the SwiftPackageList Build Tool Plugin to generate a Settings.bundle (--output-type settings-bundle), the Xcode build fails with:

Multiple commands produce
.../Build/Products/Debug-iphonesimulator/XY.app/Settings.bundle

This occurs when the app target already contains a manually created Settings.bundle with custom settings and an Acknowledgements child pane added exactly as described in the documentation.

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Steps to reproduce

1. Add SwiftPackageList as an Xcode Build Tool Plugin to an iOS app target
2. Configure the plugin to run with --output-type settings-bundle
3. In the same app target, add your own Settings.bundle (with custom settings / Root.plist)
4. Add the Acknowledgements child pane to Root.plist exactly as described here:
   https://github.com/FelixHerrmann/swift-package-list?tab=readme-ov-file#settings-bundle
5. Build the app

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Expected behavior

• It should be possible to combine:
  • a manually maintained Settings.bundle (custom settings), and
  • automatically generated acknowledgements
• The build should not fail, and only a single Settings.bundle should be embedded in the final app.

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Actual behavior

• Xcode fails the build with a “Multiple commands produce …/Settings.bundle” error
• Xcode attempts to copy:
  • the manually added Settings.bundle, and
  • the Settings.bundle generated by the build tool plugin
    into the same destination path inside the app bundle

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Environment

• Xcode: 26.2
• macOS: 26.2
• SwiftPackageList version: 4.9.0
• Target: iOS 26.2

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Notes

The documentation explains how to set up Acknowledgements.plist as a child pane, but does not describe how this should work when the tool is used as an Xcode Build Tool Plugin, where the plugin always produces its own Settings.bundle.

This makes it unclear how to combine custom app settings with generated acknowledgements without hitting a duplicate bundle build error.

[FelixHerrmann]

Hey @benjaminkech, unfortunately this is not possible right now. The plugin config could be extended to allow customizing the output path here but it is actually a permission issue of the plugin sandbox.

I see the following alternatives for your scenario:

• use a run script phase instead of the plugin; this requires installing the CLI tool in all your dev and CI environments but does exactly what you want to achieve
• use any of the other output types (likely json) and implement it in the app's UI; checkout this section for all possible options, there is API for reading the files in the Bundle and prebuilt UI components in both SwiftUI and UIKit
• only use the Settings.bundle for acknowledgments and move the settings into the app's UI

[benjaminkech]

Thanks for the explanation, @FelixHerrmann !