[Lyokone]

Description

Backport of #18856 to the 4.x line (base release/4.x, cut from BoM-v4.20.0).

Security fix: Cloud Firestore's embedded gRPC root-certificate bundle still trusted compromised eMudhra CA roots (firebase-ios-sdk#16930). This pins the Firebase iOS SDK to 12.19.3 for both CocoaPods and SPM on 4.x:

• CocoaPods: firebase_core/ios/firebase_sdk_version.rb → 12.19.3

• SPM: firebaseSdkVersion in every plugin's iOS/macOS Package.swift → 12.19.3 (4.x predates the single SPM pin from chore(apple): give Swift Package Manager its own Firebase SDK pin #18739)

• CocoaPods resolution: Firebase 12.19.3 is a partial release (only Firebase, FirebaseCore, FirebaseFirestore, FirebaseFirestoreInternal). firebase_app_check (iOS) now depends on Firebase/AppCheck (matching macOS) instead of FirebaseAppCheck ~> 12.19.3, and firebase_analytics allows FirebaseAnalytics ~> 12.19.0 instead of exactly 12.19.3.

• Firestore example Podfiles (iOS/macOS): dropped the invertase/firestore-ios-sdk-frameworks override, which has no 12.19.3 tag, so the e2e builds use the patched FirebaseFirestore from trunk.

Verified published: firebase-ios-sdk tag 12.19.3 and FirebaseFirestore 12.19.3 on CocoaPods trunk.

Changelog notes

• Windows: Firestore on Windows (C++ SDK) is also affected and will be covered in a follow-up firebase_core release once the C++ SDK patch is published.
• Immediate workaround (CocoaPods): add $FirebaseSDKVersion = '12.19.3' at the top of ios/Podfile, then run pod update FirebaseFirestore.
• Precompiled Firestore frameworks (invertase/firestore-ios-sdk-frameworks): no 12.19.3 tag yet; users of that repo stay on the unpatched 12.19.0 until one is published.
• SPM users must upgrade to the new firebase_core release.

Breaking Change

• No, this is not a breaking change.

[gemini-code-assist]

Code Review

This pull request updates the Firebase SDK version from 12.19.0 to 12.19.3 across multiple iOS and macOS package configuration files. There are no review comments to address for this change.