Android and iOS Fastfiles for Flutter App

android.rb

# android/fastlane/Fastfile
update_fastlane

default_platform(:android)

platform :android do

  lane :bump_version_code do
    versionCode = File.read("metadata/versionCode").to_i
         versionCode = versionCode + 1

         f = File.new("metadata/versionCode", "w")
         f.write(versionCode)
         f.close
         versionCode
  end

  desc "Deploy a new version to the Google Play"
  lane :prod do
    versionCode = bump_version_code
  
    sh("flutter", "build", "appbundle", "--build-number=#{versionCode}", "--dart-define-from-file=assets/config.json")
  
    upload_to_play_store(
      track: 'production',
      aab: '../build/app/outputs/bundle/release/app-release.aab',
    )
  
    send_slack_notification(message: "New production version #{versionCode} has been pushed to Google Play!")
  end
  
  desc "Deploy a new version to the beta test track of Google Play"
  lane :internal do
    versionCode = bump_version_code
  
    sh("flutter", "build", "appbundle", "--build-number=#{versionCode}", "--dart-define-from-file=assets/config.json")
  
    upload_to_play_store(
      track: 'internal',
      aab: '../build/app/outputs/bundle/release/app-release.aab',
    )
  
    send_slack_notification(message: "New internal version #{versionCode} has been pushed to Google Play!")
  end
  
  desc "Send a message to Slack"
  lane :send_slack_notification do |options|
    message = options[:message] || "A new update has been pushed!"
    slack(
      message: message,
      success: true,
      slack_url:  ENV["SLACK_WEBHOOK_URL"]
    )
  end

end

ios.rb

# ios/fastlane/Fastfile
update_fastlane

default_platform(:ios)

platform :ios do
  
  lane :bump_version_code do
    versionCode = File.read("metadata/versionCode").to_i
    versionCode = versionCode + 1
    
    f = File.new("metadata/versionCode", "w")
    f.write(versionCode)
    f.close
    versionCode
  end
  
  lane :bump_version_name do
    version_name = File.read("metadata/versionName").to_i
    version_name = version_name + 1
    
    f = File.new("metadata/versionName", "w")
    f.write(version_name)
    f.close
    version_name
  end
  
  desc "Push a new release build to the App Store"
  lane :prod do
    versionCode = bump_version_code
    version_name = bump_version_name 
    sh("flutter","build","ipa","--build-name", "#{version_name}","--dart-define-from-file=assets/config.json")
    upload_to_app_store(ipa: "../build/ios/ipa/myApp.ipa",
    submit_for_review: true,
    automatic_release: true,
    force: true,
    submission_information: {
    "export_compliance_uses_encryption": false,
    "add_id_info_uses_idfa": false}
    )
    
    send_slack_notification(message: "New production version #{versionCode} has been pushed to App Store!")  
  end
  
  desc "Push a new beta build to TestFlight"
  lane :beta do
    versionCode = bump_version_code
    version_name = bump_version_name
    sh("flutter","build","ipa","--build-name", "#{version_name}","--dart-define-from-file=assets/config.json")
    upload_to_testflight(ipa: "../build/ios/ipa/myApp.ipa")
    
    send_slack_notification(message: "New internal version #{versionCode} has been pushed to TestFlight!")
  end
  
  desc "Send a message to Slack"
  lane :send_slack_notification do |options|
    message = options[:message] || "A new update has been pushed!"
    slack(
    message: message,
    success: true,
    slack_url: ENV["SLACK_WEBHOOK_URL"]
    )
  end
end

I'm encountering an issue when running Fastlane with the following directory structure:

flutter_advanced_topics/
└── fastlane/
    ├── Fastfile
    ├── android.rb
    └── iOS.rb

The Fastfile is configured to load android.rb and iOS.rb using the following code:

Fastfile:

default_platform(:android)

# Load Android-specific lanes
eval(File.read(File.expand_path("fastlane/android.rb", __dir__)))

# Load iOS-specific lanes
eval(File.read(File.expand_path("fastlane/iOS.rb", __dir__)))

I am running the following commands:

• For Android Production: fastlane android prod
• For Android Internal: fastlane android internal
• For iOS Production: fastlane ios prod
• For iOS Internal: fastlane ios internal

However, when I try to run these commands, I get the following error:

[17:55:07]: Error accessing file, this might be due to fastlane's directory handling
Fastfile:6:in `read': No such file or directory @ rb_sysopen - /flutter_advanced_topics/fastlane/fastlane/android.rb (Errno::ENOENT)
        from Fastfile:6:in `parsing_binding'

It seems that Fastlane is incorrectly looking for the android.rb file at the path /flutter_advanced_topics/fastlane/fastlane/android.rb instead of /flutter_advanced_topics/fastlane/android.rb, which is where the file actually resides.

What I’ve tried:

• Ensured that android.rb and iOS.rb are correctly placed inside the fastlane/ folder.
• Verified the directory paths in Fastfile and confirmed that android.rb and iOS.rb are being loaded using the correct paths.

Expected Behavior:

Fastlane should correctly load the android.rb and iOS.rb files from the fastlane/ directory.

Environment:

• Fastlane version: 2.225.0
• Ruby version: 3.3.0

Can anyone help me resolve this issue? Thank you in advance!