FR: Add support for dynamically linked libraries with Swift Package Manager

[Brian-Co]

Feature proposal

• Firebase Component: All

As of today, Firebase integration through Swift Package Manager provides statically linked libraries only. See: https://firebase.google.com/docs/ios/link-firebase-static-dynamic?hl=en

Dynamic linkage has been available through Cocoapods since Firebase version 7.0.0.

Is dynamically linked libraries support for Swift Package Manager planned to be added? And if yes, when could we see that being shipped?

Thanks a lot!

[paulb777]

Just like CocoaPods, there are no plans to support dynamic libraries for the binary part of the distribution (Firebase Analytics). For the rest, it should be feasible, especially if there's a way for the library to control the linking like CocoaPods allows from the Podfile.

With a bit of searching, it's not clear to me if and how it's possible in Swift PM - but definitely open to suggestions and PRs.

[mortenbekditlevsen]

In Package.swift you can add type: .dynamic to a library to have it link dynamically.
Some packages supply the same targets as both dynamic and static by giving one of the libraries a different name.

[mortenbekditlevsen]

Not certain how the internal dependencies are handled - of course it's no good if two dynamic libraries statically link to shared functionality...

[paulb777]

Thanks @mortenbekditlevsen. I'm not enthusiastic about doubling the number of Firebase SPM products, but can consider if there's enough interest.

I'd much prefer a solution that lets the library consumer decide like CocoaPods's use_frameworks! and use_frameworks! :linkage => :static alternatives.

[mortenbekditlevsen]

Right - I don't know why control is placed at the point of the author rather than the consumer, but I guess there must be some reason for it to be like that.

[paulb777]

Given Apple's announcements around mergeable libraries at WWDC 23 and associated runtime speedups for dynamic libraries, let's consider switching our binary distribution builds to dynamic libraries in Firebase 11.

[jeffremer]

I'm curious if this would include the transitive Google dependencies or other Google frameworks - currently GoogleAppMeasurement is a transitive dependency for FirebaseAnalytics and GoogleMobileAds, so we're getting duplicate symbol warnings when trying to use FirebaseAnalytics from one target (the main app) and with GoogleMobileAds used by another target (our own Advertising wrapper).

[paulb777]

Yes, GoogleAppMeasurement and other Firebase dependencies will be included.