Use @_implementationOnly import for FirebaseCoreExtension (#9887)

Using a regular import caused internal Core APIs to be surfaced to end
users.

Author: ryanwilson

FirebaseFunctions/CHANGELOG.md

@@ -1,5 +1,6 @@
 # 9.2.0
 - [fixed] Fixed regressions in error code processing introduced in 9.0.0. (#9855)
+- [fixed] Importing FirebaseFunctions no longer exposes internal FirebaseCore APIs. (#9884)
 
 # 9.0.0
 - [changed] The FirebaseFunctionsSwift library has been removed. All of its APIs are now included

FirebaseFunctions/Sources/Functions.swift

@@ -16,7 +16,6 @@ import Foundation
 import FirebaseAppCheckInterop
 import FirebaseAuthInterop
 import FirebaseCore
-import FirebaseCoreExtension
 import FirebaseMessagingInterop
 import FirebaseSharedSwift
 #if COCOAPODS
@@ -25,6 +24,9 @@ import FirebaseSharedSwift
   import GTMSessionFetcherCore
 #endif
 
+// Avoids exposing internal FirebaseCore APIs to Swift users.
+@_implementationOnly import FirebaseCoreExtension
+
 /// File specific constants.
 private enum Constants {
   static let appCheckTokenHeader = "X-Firebase-AppCheck"

FirebaseFunctions/Sources/Internal/FunctionsComponent.swift

@@ -16,9 +16,11 @@ import Foundation
 import FirebaseAppCheckInterop
 import FirebaseAuthInterop
 import FirebaseCore
-import FirebaseCoreExtension
 import FirebaseMessagingInterop
 
+// Avoids exposing internal FirebaseCore APIs to Swift users.
+@_implementationOnly import FirebaseCoreExtension
+
 @objc(FIRFunctionsProvider)
 protocol FunctionsProvider {
   @objc func functions(for app: FirebaseApp,

FirebaseStorage/CHANGELOG.md

@@ -1,3 +1,6 @@
+# 9.2.0
+- [fixed] Importing FirebaseStorage no longer exposes internal FirebaseCore APIs. (#9884)
+
 # 9.0.0
 - [changed] The FirebaseStorageSwift library has been removed. All of its APIs are now included
   in the FirebaseStorage library. Please remove references to FirebaseStorageSwift from Podfiles and

FirebaseStorage/Sources/Storage.swift

@@ -16,10 +16,12 @@ import Foundation
 
 import FirebaseStorageInternal
 import FirebaseCore
-import FirebaseCoreExtension
 import FirebaseAppCheckInterop
 import FirebaseAuthInterop
 
+// Avoids exposing internal FirebaseCore APIs to Swift users.
+@_implementationOnly import FirebaseCoreExtension
+
 /**
  * Firebase Storage is a service that supports uploading and downloading binary objects,
  * such as images, videos, and other files to Google Cloud Storage. Instances of `Storage`

FirebaseStorage/Sources/StorageComponent.swift

@@ -16,7 +16,9 @@ import Foundation
 import FirebaseAppCheckInterop
 import FirebaseAuthInterop
 import FirebaseCore
-import FirebaseCoreExtension
+
+// Avoids exposing internal FirebaseCore APIs to Swift users.
+@_implementationOnly import FirebaseCoreExtension
 
 @objc(FIRStorageProvider)
 protocol StorageProvider {