flutter build ios-framework fails when plugin declares WatchOS target

[fwagner]

Background

Our app includes a Watch App for iOS. To keep all watch related code contained in one place, we have created a plugin that contains both an iOS and a watchOS target in its podspec:

Pod::Spec.new do |s|
  s.name             = 'watch_flutter_plugin'
  s.version          = '1.0.0'
  s.summary          = 'Flutter plugin for watchOS app.'
  s.ios.source_files = 'Classes/src/ios/**/*', 'Classes/src/shared/**/*'
  s.ios.dependency 'Flutter'
  s.ios.deployment_target = '14.0'
  s.watchos.deployment_target = '8.0'
  s.watchos.source_files = 'Classes/src/watchos/**/*', 'Classes/src/shared/**/*'
  s.watchos.resources = 'Assets/**/*'
end

Note: This setup works fine when building the app with flutter build ios, the issue only occurs on flutter build iOS-framework.

Steps to Reproduce

1. Add a plugin to your app that declares both an iOS and a watchOS target in its podspec file.
2. Run flutter build ios-framework command

Logs

Logs

flutter build ios-framework --release --target lib/main/main.dart --verbose

(Logs redacted due to confidentiality, full logs are available on request)

                      /<redacted>/ios/Classes/src/watch
                      os/companionAppBridge/CompanionAppBridge.swift:10:8: error: no such module 'WatchKit'
                      import WatchKit
                             ^

[✓] Flutter (Channel stable, 2.5.4-0.0.pre.1, on macOS 12.4 21F79 darwin-x64, locale de-DE)
    • Flutter version 2.5.4-0.0.pre.1 at /Users/.../flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 7538428275 (vor 4 Wochen), 2022-05-25 09:03:12 -0700
    • Engine revision d3ea636dc5
    • Dart version 2.14.4

[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
    • Android SDK at /Users/.../Library/Android/sdk
    • Platform android-31, build-tools 31.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jre/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.12+0-b1504.28-7817840)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 13.2.1, Build version 13C100
    • CocoaPods version 1.11.2

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2021.2)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.12+0-b1504.28-7817840)

[✓] VS Code (version 1.63.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.36.0

[✓] Connected device (1 available)
    • Chrome (web) • chrome • web-javascript • Google Chrome 102.0.5005.115

Preliminary analysis

The cause for the error seems to be that the build ios-framework command issues a xcodebuild command that builds all targets with SDK iphoneos (and iphonesimulator in the next command) regardless of the actual platform of the target. This obviously fails for the watchos target as this includes frameworks that are not available in iphoneos SDK.

[huycozy]

Hi @fwagner, thanks for filing the issue.
Flutter doesn't yet fully support watchOS. There's an open #28901 you can refer for further updates.
Closing this as a duplicate.

[fwagner]

@huycozy I have to slightly disagree regarding this being a duplicate of #28901. This is not meant to have full WatchOS support for Flutter.
In my opinion this issue is more along the lines of the tooling having to support a Flutter iOS app while having a native WatchIOS App.

[huycozy]

@fwagner
I reopen the issue for further investigation.
You are using the old Flutter version 2.5.4-0.0.pre.1, the latest Flutter stable is 3.0.3 and the master is 3.1.0-0.0.pre.1376. Please try upgrading them and retry to see if this issue still reproduces?

[fwagner]

Thanks @huycozy!

I tried with both the latest versions from stable and master channels and can still reproduce the issue with both of them.

Flutter 3.0.3 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 676cefaaff (vor 5 Tagen) • 2022-06-22 11:34:49 -0700
Engine • revision ffe7b86a1e
Tools • Dart 2.17.5 • DevTools 2.12.2

Flutter 3.1.0-0.0.pre.1376 • channel master • https://github.com/flutter/flutter.git
Framework • revision 3598f20002 (vor 13 Stunden) • 2022-06-26 18:19:04 -0400
Engine • revision ee56813c14
Tools • Dart 2.18.0 (build 2.18.0-228.0.dev) • DevTools 2.14.1

[huycozy]

@fwagner
Do you find this issue #92294 similar to yours?
Also, try the solution in #92294 (comment) to see if it helps you to solve the issue.

[github-actions]

Without additional information, we are unfortunately not sure how to resolve this issue. We are therefore reluctantly going to close this bug for now.
If you find this problem please file a new issue with the same description, what happens, logs and the output of 'flutter doctor -v'. All system setups can be slightly different so it's always better to open new issues and reference the related ones.
Thanks for your contribution.

[jmagman]

Reopening, there seems to be enough info here to reproduce, and it seems different than #92294 since flutter build ios succeeded.