Resolving Flutter Desktop MacOS Directory Creation Issues Outside Project Folder

Have you encountered the `FileSystemException` while trying to create a directory outside of the Flutter project folder on MacOS? This guide explains the issue and provides a clear solution.
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Flutter Desktop MacOS Directory Creation Issues

As a developer using Flutter for desktop applications, you may face various hurdles while building your app. One common problem emerges when you try to create a directory outside of your project folder on MacOS. This can lead to frustrating errors, specifically the FileSystemException, which can halt your progress and throw you off your game.

In this guide, we'll dive into a scenario where a developer attempted to create a directory outside of their Flutter project on MacOS Pro Big Sur V11.6 and encountered difficulties. We’ll explain the issue in depth and provide a straightforward solution.

The Problem

When the developer tried to create a directory using the directory.createSync(recursive: true); command from the dart:io library, they encountered the following error message:

[[See Video to Reveal this Text or Code Snippet]]

Despite changing the Security & Privacy settings on their Mac to grant Full Disk Access to both Visual Studio Code and Terminal, the issue persisted.

Key Points About the Issue:

Error Type: FileSystemException indicates that the operation was not permitted.

Attempted Command: directory.createSync(recursive: true); was used to create the directory.

OS Version: The problem occurred on MacOS Pro Big Sur V11.6.

The Solution

After investigating the issue, the developer identified the root cause: the app was sandboxed by default. This means that the app didn't have the necessary permissions to create directories beyond its designated space. Here’s how to resolve the issue:

Steps to Remove Sandboxing:

Edit the Entitlements File:

Navigate to the macos build folder of your Flutter project.

Locate the entitlements file, which controls app permissions.

Remove Sandboxing Attributes:

Look for the line that includes com.apple.security.app-sandbox and remove it completely from the file.

This step effectively disables the sandboxing feature, allowing your Flutter app the necessary permissions to create directories outside of its project space.

Rebuild Your Application:

After editing the entitlements file, rebuild your Flutter application using the command:

[[See Video to Reveal this Text or Code Snippet]]

This step ensures that your changes take effect in the application bundle.

Testing the Solution:

Once you've taken the steps above, try running your application again and executing the directory creation command. You should find that it now works seamlessly without throwing the previous exceptions.

Conclusion

Creating directories outside your Flutter project folder on MacOS is a known issue when dealing with sandboxing. However, by following the outlined steps to edit your entitlements file and disable the sandboxing feature, you can easily overcome this barrier. Remember that with great power comes great responsibility, so ensure your application handles file permissions appropriately.

Don't let permissions hold you back in your Flutter journey! With these insights, you'll be better equipped to handle directory creation issues on MacOS efficiently.