docs(firebase_login): add firebase login example app

[thisissandipp]

Description

Add a Flutter app example demonstrating how to handle Firebase authentication using Riverpod.

• sign up, and sign in with email and password
• sign in with google
• error handling, display error message
• navigation based on the user's authentication state

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]).

• [ ] I have updated the CHANGELOG.md of the relevant packages. Changelog files must be edited under the form:

  ## Unreleased fix/major/minor
  
  - Description of your change. (thanks to @yourGithubId)
  

• [ ] If this contains new features or behavior changes, I have updated the documentation to match those changes.

Summary by CodeRabbit

• New Features

  • Added Firebase authentication with email/password and Google Sign-In
  • Implemented user sign-up, sign-in, and sign-out functionality
  • Created home screen displaying user information
  • Introduced README with setup instructions and screenshots

• Documentation

  • Added project configuration files, metadata, and .gitignore

• Testing

  • Implemented widget tests for authentication flows
  • Added test utilities for mocking authentication repository

• Development Tools

  • Configured Riverpod for state management
  • Set up analysis options and linting configurations
  • Added build and development dependency configurations
  • Introduced dependency overrides for local development

[coderabbitai[bot]]

Walkthrough

This pull request introduces a comprehensive Firebase login example application using Flutter and Riverpod. The project establishes a complete authentication flow with sign-up, sign-in, and home pages, integrating Firebase authentication with Google Sign-In. It includes detailed error handling and state management using Freezed and Riverpod. The project is configured with metadata, linting rules, dependency management, and extensive .gitignore settings. Additionally, it provides documentation, generated code for providers, and a suite of widget tests covering authentication flows and UI components.

Changes

File	Change Summary
examples/firebase_login/.gitignore	Added comprehensive ignore patterns for Flutter, Firebase, and development environments.
examples/firebase_login/.metadata	Created project metadata file with Flutter configuration details and migration tracking.
examples/firebase_login/README.md	Added documentation with app features, screenshots, and setup instructions.
examples/firebase_login/analysis_options.yaml	Configured linting and analysis options including Riverpod lint plugin and error ignores.
examples/firebase_login/lib/auth/auth_repository.dart	Implemented authentication repository with Firebase and Google Sign-In methods, error handling, and Riverpod providers.
examples/firebase_login/lib/auth/auth_repository.g.dart	Generated Riverpod provider code for authentication repository and related services.
examples/firebase_login/lib/auth/user.dart	Introduced immutable User model class with authentication state helpers using Freezed.
examples/firebase_login/lib/auth/user.freezed.dart	Generated immutable User class implementation using Freezed.
examples/firebase_login/lib/home/home.dart	Created home page widget displaying user info and logout button with sign-out functionality.
examples/firebase_login/lib/main.dart	Created main application entry point initializing Firebase and managing auth state with Riverpod.
examples/firebase_login/lib/main.g.dart	Generated Riverpod provider code for user authentication stream.
examples/firebase_login/lib/sign_in/sign_in.dart	Developed sign-in page with email/password and Google authentication, state management, and error handling.
examples/firebase_login/lib/sign_in/sign_in.freezed.dart	Implemented sign-in state management using Freezed with states: initial, loading, success, failure.
examples/firebase_login/lib/sign_up/sign_up.dart	Implemented sign-up page with email registration, state management, and error handling.
examples/firebase_login/lib/sign_up/sign_up.freezed.dart	Defined sign-up state management using Freezed with states: initial, loading, success, failure.
examples/firebase_login/pubspec.yaml	Defined project dependencies, environment constraints, and dev dependencies.
examples/firebase_login/pubspec_overrides.yaml	Added dependency overrides for local Riverpod package development.
examples/firebase_login/test/app_test.dart	Introduced widget tests for the App component verifying auth-based navigation.
examples/firebase_login/test/home_test.dart	Added widget test for HomePage verifying sign-out interaction triggers signOut method.
examples/firebase_login/test/pump_app.dart	Created mock authentication repository and widget tester extension for injecting mocks.
examples/firebase_login/test/sign_in_test.dart	Established widget tests for SignInPage verifying sign-in method calls on user interaction.
examples/firebase_login/test/sign_up_test.dart	Validated sign-up functionality with widget test verifying sign-up method call on form submission.

Poem

🐰 A Rabbit's Authentication Tale 🔐
With Firebase and Riverpod's might,
Login flows now shine so bright!
Sign in, sign up, with Google's grace,
Security dances at a playful pace!
~ CodeRabbit's Authentication Poet 🚀

[!TIP]

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📥 Commits

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📒 Files selected for processing (1)

• examples/firebase_login/lib/auth/user.dart (1 hunks)

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• examples/firebase_login/lib/auth/user.dart

⏰ Context from checks skipped due to timeout of 90000ms (8)

• GitHub Check: Redirect rules - river-pod
• GitHub Check: Header rules - river-pod
• GitHub Check: Pages changed - river-pod
• GitHub Check: riverpod_lint (master, packages/riverpod_lint)
• GitHub Check: changelog
• GitHub Check: check_generation
• GitHub Check: build (stable, packages/flutter_riverpod/example)
• GitHub Check: build (stable, examples/pub)

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[rrousselGit]

I don't like the proposed folder architecture. Please don't use kind-based folders such as models/ providers/ repositories.

Instead use feature-based folders like home/login_page/settings/ ...

[rrousselGit]

Thanks for this!

I gave a very quick look at the current state, and suggested broad changes. I'll look move closely at the details once we agree on the basics :)

Note: It'd be useful to update the README with:

• instructions on how folks can run the example (so using setting up their firebase.json & co)
• screenshots of the example in various scenarios, to allow folks to easily see what the example can do

[thisissandipp]

Thanks for the quick review and feedback, Remi.

I'll make the changes as suggested, and I'll make sure to verify the architecture with you before I start moving things around, so we’re on the same page. I'll add instructions to the README as well.

[rrousselGit]

Cool :)

If you have any doubt, feel free to ask questions!

[thisissandipp]

@rrousselGit I have considered your suggestions and come up with this structure, what do you think about it?

lib/
├── auth/
│   ├── auth_repository.dart
│   ├── user.dart
├── app/
│   ├── app_state.dart  // e.g., app state provider (auth state can be renamed)
│   ├── app.dart   // MaterialApp widget, route initialization
├── sign_in/
│   ├── sign_in_page.dart
│   ├── sign_in_state.dart // Providers related to sign-in
├── sign_up/
│   ├── sign_up_page.dart
│   ├── sign_up_state.dart // Providers related to sign-up
├── home/
│   ├── home_page.dart
├── main.dart
├── provider_observer.dart

Also, I noticed your comment regarding app_provider_observer.dart is not useful in this context. It can help debug during the development process.

If you feel it doesn't add enough value here, I'm happy to remove it! I just thought it might be beneficial to keep it for the debugging phase and as a teaching point for others reviewing the example.

[rrousselGit]

@rrousselGit I have considered your suggestions and come up with this structure, what do you think about it?

Must better!

Also, I noticed your comment regarding app_provider_observer.dart is not useful in this context. It can help debug during the development process.

If you feel it doesn't add enough value here, I'm happy to remove it! I just thought it might be beneficial to keep it for the debugging phase and as a teaching point for others reviewing the example.

I think it's better to remove it.

IMO, less is more. The more noise we add, the harder it is for people to find what they are looking for.
In that sense, I'd even consider removing the snackbar logic.

Demonstrating how to do those things is valuable. But it should likely be a separate example instead.
One example = one goal.

This one is about Firebase auth.

We can have another example for demonstrating logging (including Crashlytics interaction).
And another one for how to deal with loading/error pages ; be it snackbars or "Oopsy" screens.

If this example contains something, it should be closely related to Firebase Auth.

[rrousselGit]

Actually about the folder structure, I'd still change a few things.

What I'd personally do is:

lib/
├── sign_in.dart // Both the view + provider
├── sign_up.dart // Both the view + provider again
├── home.dart // View + whatever home-state there is
├── main.dart // Including whatever was from the proposed "app" folder"

For UI, I usually go with "one file per route".

It's good to keep the provider and its view in the same file. No need to separate them