[Infra] Move 'firestore' workflow to Xcode 16

.github/workflows/firestore.yml

@@ -333,7 +333,7 @@ jobs:
     if: |
       (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') ||
       (github.event_name == 'pull_request')
-    runs-on: macos-14
+    runs-on: macos-15
 
     strategy:
       matrix:
@@ -362,7 +362,7 @@ jobs:
     if: |
       (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') ||
       (github.event_name == 'pull_request')
-    runs-on: macos-14
+    runs-on: macos-15
     strategy:
       matrix:
         podspec: [
@@ -377,7 +377,7 @@ jobs:
     - name: Setup Bundler
       run: ./scripts/setup_bundler.sh
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_15.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
 
     - name: Pod lib lint
       # TODO(#9565, b/227461966): Remove --no-analyze when absl is fixed.
@@ -406,19 +406,11 @@ jobs:
           '--use-static-frameworks',
           '',
         ]
-        os: [macos-14, macos-13]
-        # TODO: grpc and its dependencies don't build on Xcode 15 for macos because their minimum macos is lower than 10.11.
-        exclude:
-          - os: macos-13
-            platforms: 'macos'
+        os: [macos-15, macos-14]
         # Skip matrix cells covered by pod-lib-lint job.
-          - os: macos-13
-            platforms: 'ios'
-        include:
+        exclude:
           - os: macos-15
-            xcode: Xcode_16.2
-          - os: macos-13
-            xcode: Xcode_15.2
+            platforms: 'ios'
     runs-on: ${{ matrix.os }}
 
     steps:
@@ -448,6 +440,8 @@ jobs:
       cache_key: ${{ steps.generate_cache_key.outputs.cache_key }}
     steps:
       - uses: actions/checkout@v4
+      - name: Xcode
+        run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
       - name: Generate Swift Package.resolved
         id: swift_package_resolve
         run: |
@@ -472,11 +466,8 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: macos-13
-            xcode: Xcode_15.2
-            target: iOS
           - os: macos-14
-            xcode: Xcode_15.4
+            xcode: Xcode_16.2
             target: iOS
           - os: macos-15
             xcode: Xcode_16.2
@@ -514,12 +505,14 @@ jobs:
     if: |
       (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') ||
       (github.event_name == 'pull_request' && needs.changes.outputs.changed == 'true')
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
     - uses: actions/checkout@v4
     - uses: mikehardy/buildcache-action@c87cea0ccd718971d6cc39e672c4f26815b6c126
       with:
         cache_key: spm-binary
+    - name: Xcode
+      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
     - name: Initialize xcodebuild
       run: scripts/setup_spm_tests.sh
     - name: iOS Build Test

Firestore/Swift/Source/Codable/DocumentID.swift

@@ -20,7 +20,7 @@
   @_exported import FirebaseFirestoreInternal
 #endif // SWIFT_PACKAGE
 
-@_implementationOnly import FirebaseCoreExtension
+internal import FirebaseCoreExtension
 import FirebaseSharedSwift
 
 extension CodingUserInfoKey {