Modify SDK build Cocoapods inclusion to use frameworks instead of libraries

[jonsimantov]

Description

Provide details of the change, and generalize the change in the PR title above.

Upcoming release 9.0.0 will require that Cocoapods be included as frameworks, not as a libraries. This change modifies the existing CMake build to be able to build via frameworks. This requires adding a few different locations to the include paths, as the paths are different when using frameworks (and in a few cases e.g. GTMSesionFetcher, headers are no longer in the public location).

This PR also modifies the integration tests to add "use_frameworks! :linkage => :static" to each one; the static linkage is required for tvOS, otherwise a bug in xcodebuild causes the tvOS build to accidentally import the iOS frameworks. If the xcodebuild command-line ever fixes this issue, we can remove the static linkage workaround.

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Testing

Describe how you've tested these changes. Link any manually triggered Integration tests or CPP binary SDK Packaging Github Action workflows, if applicable.

Integration test and cpp packaging runs will both be verified.

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Type of Change

Place an x the applicable box:

• Bug fix. Add the issue # below if applicable.
• New feature. A non-breaking change which adds functionality.
• Other, such as a build process or documentation change.

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Notes

• Bug fixes and feature changes require an update to the Release Notes section of release_build_files/readme.md.
• Read the contribution guidelines CONTRIBUTING.md.
• Changes to the public API require an internal API review. If you'd like to help us make Firebase APIs better, please propose your change in a feature request so that we can discuss it together.

[github-actions]

✅  Integration test succeeded!

Requested by @jonsimantov on commit 6c2f067
Last updated: Fri Apr 22 20:47 PDT 2022
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[jonsimantov]

@sunmou99 The build_testapps.py script seems to be messing something up about adding the frameworks to the tvOS builds now, with this Cocoapods change. I tried looking into what might be happening but I haven't been able to figure it out. Can you try to reproduce the issue on this branch?

[sunmou99]

@sunmou99 The build_testapps.py script seems to be messing something up about adding the frameworks to the tvOS builds now, with this Cocoapods change. I tried looking into what might be happening but I haven't been able to figure it out. Can you try to reproduce the issue on this branch?

tvOS platform shouldn't contain CoreTelephony:
https://github.com/google/GoogleDataTransport/search?q=coretelephony
But, we included it anyway.
error: CoreTelephony is not available when building for tvOS Simulator. (in target 'GoogleDataTransport-iOS' from project 'Pods')

We could change the Podfile and remove the unwanted target it before we build the testapp

[jonsimantov]

@sunmou99 The build_testapps.py script seems to be messing something up about adding the frameworks to the tvOS builds now, with this Cocoapods change. I tried looking into what might be happening but I haven't been able to figure it out. Can you try to reproduce the issue on this branch?

tvOS platform shouldn't contain CoreTelephony: https://github.com/google/GoogleDataTransport/search?q=coretelephony But, we included it anyway. error: CoreTelephony is not available when building for tvOS Simulator. (in target 'GoogleDataTransport-iOS' from project 'Pods')

We could change the Podfile and remove the unwanted target it before we build the testapp

After some more research, it seems that this is a known issue with command-line xcodebuild using the new build system. When you have multiple targets with different platforms, the command-line build seems to mistakenly include the framework dependencies from Cocoapods into all of the targets. Unfortunately, we can't use the legacy build system as it doesn't support .xcframeworks. So it seems like the best workaround is to have platform-specific Podfiles (edited on the fly by the script).

I am testing one more possible fix, setting the linkage to static - this worked one time I tested it, though it still printed some warnings.

[jonsimantov]

Everything looks good except an unrelated Firestore error, gonna go ahead and merge this.