Flutter Version Management (FVM): Explained

Flutter Version Management (FVM) is an essential tool for Flutter developers that streamlines the process of managing multiple Flutter SDK versions across different projects. As Flutter evolves rapidly with frequent updates, having a robust version management system becomes crucial for maintaining project stability. This comprehensive guide will walk you through everything you need to know about FVM, from installation to advanced usage scenarios.

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Why You Need Flutter Version Management

Before diving into the technical details, let's understand why FVM is important for Flutter developers:

1. Project-Specific Flutter Versions: Different projects may require different Flutter SDK versions based on package compatibility or client requirements.
2. Team Consistency: Ensures all team members use the same Flutter version, eliminating "works on my machine" issues.
3. Easy SDK Switching: Quickly switch between stable, beta, or dev channels without time-consuming reinstallations.
4. Multiple Project Support: Work on various projects simultaneously without version conflicts.
5. Testing New Releases: Safely experiment with new Flutter versions without affecting your stable production projects.

Installation

Let's start by installing FVM on your system. The installation process differs slightly depending on your operating system:

For macOS:

Using Homebrew:

brew tap leoafarias/fvm
brew install fvm

Using install script:

curl -fsSL https://fvm.app/install.sh | bash

For Windows:

Using Chocolatey:

choco install fvm

Or download the standalone package from the FVM GitHub repository.

For Linux:

Using the install script:

curl -fsSL https://fvm.app/install.sh | bash

Global Activation

After installing FVM, activate it globally:

dart pub global activate fvm

Basic FVM Commands and Usage

Now that you have FVM installed, let's explore the essential commands for managing Flutter SDK versions.

Installing Flutter Versions

To install a specific Flutter version:

fvm install 3.16.0

You can also install a specific channel:

fvm install stable
fvm install beta
fvm install dev

For advanced users, you can even install a specific commit by using the git commit hash:

fvm install fa345b1  # Short hash
fvm install 476ad8a917e64e345f05e4147e573e2a42b379f9  # Long hash

Setting a Flutter Version for Your Project

To set a specific Flutter version for your project, navigate to your project directory and run:

fvm use 3.16.0

This command creates a .fvm folder in your project and sets up a symbolic link to the specified Flutter SDK.

To use the latest version from a specific channel:

fvm use stable

If you want to pin the channel to its current version (preventing automatic updates):

fvm use stable --pin

Listing Installed Versions

To see all the Flutter versions you've installed via FVM:

fvm list

Alternatively, you can use the shorthand:

fvm ls

Viewing Available Flutter Releases

To view all available Flutter SDK releases:

fvm releases

To filter releases by channel:

fvm releases --channel beta

Removing a Flutter Version

When you no longer need a specific Flutter version:

fvm remove 3.16.0

Setting a Global Flutter Version

To set a global Flutter version to use across your system:

fvm global 3.16.0

To unlink the global version:

fvm global --unlink

Project Configuration

After you've set up FVM for your project, you'll need to configure your development environment to use the Flutter SDK managed by FVM.

Updating .gitignore

FVM creates a symbolic link at .fvm/flutter_sdk that points to the cache of your selected Flutter version. Add this to your .gitignore:

.fvm/flutter_sdk

IDE Configurations

VS Code

Create or update .vscode/settings.json in your project with the following:

{
  "dart.flutterSdkPath": ".fvm/flutter_sdk",
  // Remove .fvm files from search
  "search.exclude": {
    "**/.fvm": true
  },
  // Remove from file watching
  "files.watcherExclude": {
    "**/.fvm": true
  }
}

Android Studio

1. Go to Languages & Frameworks > Flutter
2. Change the Flutter SDK path to the absolute path of your FVM symbolic link (e.g., /absolute-project-path/.fvm/flutter_sdk)
3. Apply the changes and restart Android Studio

To ignore the Flutter SDK root directory within Android Studio, add this to .idea/workspace.xml:

<component name="VcsManagerConfiguration">
  <ignored-roots>
    <path value="$PROJECT_DIR$/.fvm/flutter_sdk" />
  </ignored-roots>
</component>

XCode

If you're working on iOS, open Xcode, go to Build phases, and add this in Run script:

export FLUTTER_ROOT="$PROJECT_DIR/../.fvm/flutter_sdk"

Advanced FVM Features

Project Flavors

FVM supports project flavors, allowing different parts of your application to use different Flutter SDK versions:

fvm use 3.16.0 --flavor production
fvm use 3.10.0 --flavor development

To switch between flavors:

fvm use production
fvm use development

To run a Flutter command with a specific flavor:

fvm flavor production flutter build

Executing Flutter Commands with Specific Versions

The spawn command allows you to run Flutter commands with a specific SDK version:

fvm spawn 3.16.0 flutter build
fvm spawn 3.10.0 flutter test

Running Commands with Project's Flutter Version

The exec command executes commands or scripts using the project's configured Flutter version:

fvm exec melos bootstrap
fvm exec path/to/script.sh

Working with FVM in CI/CD Environments

For continuous integration, add these steps to your workflow:

1. Install FVM
2. Run fvm install
3. Use fvm flutter <command> for running Flutter commands

Example for GitHub Actions:

steps:
  - uses: actions/checkout@v3
  - name: Install FVM
    run: |
      dart pub global activate fvm
      fvm install
  - name: Build and Test
    run: |
      fvm flutter pub get
      fvm flutter test

Best Practices for Using FVM

1. Always use FVM for Flutter commands - Run Flutter commands through FVM (e.g., fvm flutter pub get) to ensure consistency.
2. Include FVM version in project documentation - Document the required Flutter version in your README to help new team members.
3. Lock Flutter version in CI/CD - Ensure your continuous integration pipeline uses the same Flutter version as your development environment.
4. Consider using --pin for stability - When using a channel like 'stable', consider pinning it to avoid automatic updates.
5. Regular cache cleanup - Periodically remove unused Flutter versions with fvm remove to save disk space.

Troubleshooting Common Issues

FVM Version Not Recognized

If your IDE isn't recognizing the Flutter version set by FVM:

1. Ensure the Flutter SDK path is correctly set in your IDE settings
2. Restart your IDE after configuration changes
3. Verify the symbolic link is correctly created with ls -la .fvm/flutter_sdk

Permission Issues

If you encounter permission errors:

1. On Unix-based systems, try sudo fvm <command>
2. Check folder permissions for the FVM cache directory

Path Issues

If Flutter commands aren't found after using FVM:

1. Ensure the Flutter SDK path is in your system PATH
2. Use absolute paths to the Flutter SDK in your scripts

Conclusion

Flutter Version Management (FVM) is an indispensable tool for modern Flutter development. By allowing precise control over Flutter SDK versions across different projects, it eliminates compatibility issues and ensures consistency across development teams.

Starting with the basics of installation and progressing to advanced features like project flavors, this guide has covered the essential aspects of using FVM effectively. By incorporating FVM into your Flutter development workflow, you can enhance productivity, maintain project stability, and seamlessly collaborate with team members.

Remember to always run Flutter commands through FVM to ensure version consistency and avoid unexpected behaviors. With proper FVM usage, you can confidently work on multiple Flutter projects with different SDK requirements and easily experiment with new Flutter versions without affecting your production code.

Happy Flutter coding with FVM!