Without use_frameworks!, "implemented in both" loader errors running tests

[paulb777]

• [X ] I've read and understood the *CONTRIBUTING guidelines and have done my best effort to follow.

Report

What did you do?

• git clone [email protected]:paulb777/imp-in-both.git
• cd imp-in-both/Example/
• pod update
• open imp-in-both.xcworkspace/
• Build and notice Xcode log

What did you expect to happen?

No warnings

What happened instead?

objc[42576]: Class PodsDummy_GoogleToolboxForMac is implemented in both /Users/paulbeusterien/Library/Developer/CoreSimulator/Devices/672B8E49-CA5F-43C5-BC66-5F8FC451D677/data/Containers/Bundle/Application/9D3FF006-692D-4621-8397-0CDB6AFAC15F/imp-in-both_Example.app/imp-in-both_Example (0x107ef3350) and /Users/paulbeusterien/Library/Developer/Xcode/DerivedData/imp-in-both-cofvyqfvbkjbeuabqmlwgyviabun/Build/Products/Debug-iphonesimulator/imp-in-both_Example.app/PlugIns/imp-in-both_Tests.xctest/imp-in-both_Tests (0x121aa1a18). One of the two will be used. Which one is undefined.
objc[42576]: Class PodsDummy_imp_in_both is implemented in both /Users/paulbeusterien/Library/Developer/CoreSimulator/Devices/672B8E49-CA5F-43C5-BC66-5F8FC451D677/data/Containers/Bundle/Application/9D3FF006-692D-4621-8397-0CDB6AFAC15F/imp-in-both_Example.app/imp-in-both_Example (0x107ef33a0) and /Users/paulbeusterien/Library/Developer/Xcode/DerivedData/imp-in-both-cofvyqfvbkjbeuabqmlwgyviabun/Build/Products/Debug-iphonesimulator/imp-in-both_Example.app/PlugIns/imp-in-both_Tests.xctest/imp-in-both_Tests (0x121aa1a68). One of the two will be used. Which one is undefined.

In a larger example, this led to test failures because of sporadic isKindOfClass failures

CocoaPods Environment

Stack

   CocoaPods : 1.5.0
        Ruby : ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-darwin17]
    RubyGems : 2.6.13
        Host : Mac OS X 10.13.3 (17D47)
       Xcode : 9.2 (9C40b)
         Git : git version 2.15.0.403.gc27cc4dac6-goog
Ruby lib dir : /Users/paulbeusterien/.rbenv/versions/2.4.0/lib
Repositories : cpdc-eap-spec - sso://cpdc-eap/spec @ a8bc771e29e69f1909d675897aa194584edc02e4
               cpdc-internal-spec - sso://cpdc-internal/spec @ 18fc461957247a2c3d86b43901cf0d3c3f1a40b2
               master - https://github.com/CocoaPods/Specs.git @ 4a324eae6501e935f5169d4c9f4b2ae9801ef0fc
               paul-specs - sso://user/paulbeusterien/Specs @ 0b01f6ce5731056ef13971c3c2e339fb1c789cff

Installation Source

Executable Path: /Users/paulbeusterien/.rbenv/versions/2.4.0/bin/pod

Plugins

claide-plugins         : 0.9.2
cocoapods-deintegrate  : 1.0.2
cocoapods-dependencies : 1.1.0
cocoapods-plugins      : 1.0.0
cocoapods-search       : 1.0.0
cocoapods-stats        : 1.0.0
cocoapods-trunk        : 1.3.0
cocoapods-try          : 1.1.0
cocoapods_debug        : 0.1.0

Project that demonstrates the issue

https://github.com/paulb777/imp-in-both

[segiddins]

does this not happen without use modular headers?

[paulb777]

Oh, you're right. It happens without use_frameworks! whether use_modular_headers! is there or not.

[ileitch]

We've a similar issue. Our setup is a framework shared by two apps in a single workspace.

With use_frameworks! pods like GoogleMaps (which are just static libs wrapped in a framework) will cause these warnings since it's implemented in both the shared framework and the apps. We have a nasty wrapper around GoogleMaps that allows us to use a single implementation of GoogleMaps at runtime from both the framework and app.

With use_modular_headers! the situation now applies to many other pods. Basically any pod that maintains global internal state won't work at expected because of the multiple implementations.

Related: #7155

[lucabartoletti]

Is this change supposed to fix #6918 ?