How can I fix the 'FIRVectorValue' undeclared error in my Flutter Firebase project on iOS?

This error means that Xcode is trying to compile code that references a Firebase Firestore identifier (FIRVectorValue) that isn’t available in the version of the iOS Firebase SDK your project is currently using. This is typically caused by version mismatches between your FlutterFire plugins and the underlying Firebase iOS SDKs. Here are some steps to resolve the issue:

1. Ensure Consistent Plugin Versions

Make sure all your FlutterFire plugins are updated to versions that are compatible with each other. In your pubspec.yaml you’re using:

YAMLCopied
  cloud_firestore: ^5.0.0
  firebase_auth: ^5.4.1
  google_sign_in: ^6.1.6
  firebase_storage: ^12.4.1
  firebase_core: ^3.10.1

Double-check the FlutterFire documentation to see if there are any specific version recommendations or migration notes when using these versions together. Also, consider updating to the latest stable versions if available.

2. Update CocoaPods and iOS Dependencies

Sometimes the error is due to outdated CocoaPods or stale dependencies. Do the following:

• Clean the Flutter build:

  SHCopied
  flutter clean
  flutter pub get

• Update CocoaPods repositories:
  Navigate to the ios directory and run:

  SHCopied
  pod repo update
  pod install

  This ensures that your Podfile.lock gets updated with the correct, compatible Firebase iOS SDK versions.

3. Check Your Podfile

Ensure that your iOS Podfile specifies a Firebase iOS SDK version that supports the new identifier. Sometimes you might need to bump the platform or explicitly set a minimum version. For example, in your Podfile you might have:

RUBYCopied
platform :ios, '10.0'

Consider increasing this if required by the newer Firebase SDKs.

4. Clean Derived Data and Rebuild from Xcode

If issues persist, clean Xcode’s derived data:

• In Xcode, go to File > Workspace Settings and click the Delete button next to Derived Data.
• Rebuild the project (or use flutter run again).

5. Verify Code Signing Settings

The message “Command CodeSign failed with a nonzero exit code” can sometimes be due to misconfigured code signing:

• Open the Xcode workspace (ios/Runner.xcworkspace).
• Go to the Signing & Capabilities tab and verify that your development team and provisioning profile settings are correct.

Following these steps should resolve the issue by ensuring that all Firebase SDK components (and their FlutterFire wrappers) are at compatible versions and that Xcode is using the updated dependencies.