Fixing `CocoaPods could not find compatible versions for pod "flutter_facebook

Today Flutter failed to compile my app to iOS with the following error:

% pod install
Analyzing dependencies
cloud_firestore: Using Firebase SDK version '8.14.0' defined in 'firebase_core'
firebase_analytics: Using Firebase SDK version '8.14.0' defined in 'firebase_core'
firebase_auth: Using Firebase SDK version '8.14.0' defined in 'firebase_core'
firebase_core: Using Firebase SDK version '8.14.0' defined in 'firebase_core'
firebase_database: Using Firebase SDK version '8.14.0' defined in 'firebase_core'
firebase_dynamic_links: Using Firebase SDK version '8.14.0' defined in 'firebase_core'
firebase_storage: Using Firebase SDK version '8.14.0' defined in 'firebase_core'
[!] CocoaPods could not find compatible versions for pod "flutter_facebook_auth":
  In Podfile:
    flutter_facebook_auth (from `.symlinks/plugins/flutter_facebook_auth/ios`)

Specs satisfying the `flutter_facebook_auth (from `.symlinks/plugins/flutter_facebook_auth/ios`)` dependency were found, but they required a higher minimum deployment target.

A few searches for that error return related tickets on GitHub, but none of them applied to me:

https://github.com/darwin-morocho/flutter-facebook-auth/issues/140#issuecomment-904233169: this person got it working after installing ffi with Rosetta. This does not apply to me since I believe I had installed the native M1 version of ffi.
https://github.com/darwin-morocho/flutter-facebook-auth/issues/140#issuecomment-903700508: this person recommends to look at the migration guide on Facebook Auth in Flutter's site. My app does not use Facebook Auth though.
https://stackoverflow.com/questions/67283211/flutter-cocoapods-could-not-find-compatible-versions-for-pod-fbsdkcorekit: in this post, they recommend running clean up commands like flutter clean, deleting Podfile.lock, etc. This did not work for me.

So I resorted to reading the error itself. It says it requires a higher minimum deployment target. In my Podfile, the deployment target was 10, which up until now, was perfect.

I looked at flutter_facebook_auth's spec, and it said the following:

% cat ios/.symlinks/plugins/flutter_facebook_auth/ios/flutter_facebook_auth.podspec 
#
# To learn more about a Podspec see http://guides.cocoapods.org/syntax/podspec.html.
# Run `pod lib lint flutter_facebook_auth.podspec' to validate before publishing.
#
Pod::Spec.new do |s|
  s.name             = 'flutter_facebook_auth'
  s.version          = '3.5.3'
  s.summary          = 'Plugin to Facebook authentication for iOS in your Flutter app'
  s.description      = <<-DESC
  Plugin to Facebook authentication for iOS in your Flutter app
                       DESC
  s.homepage         = 'https://meedu.app'
  s.license          = { :file => '../LICENSE' }
  s.author           = { 'meedu.app' => 'contacto@meedu.app' }
  s.source           = { :path => '.' }
  s.source_files = 'Classes/**/*'
  s.dependency 'Flutter'


  s.dependency 'FBSDKCoreKit', '~> 13.0.0'
  s.dependency 'FBSDKLoginKit', '~> 13.0.0'
  s.platform = :ios, '11.0'

  # Flutter.framework does not contain a i386 slice.
  s.pod_target_xcconfig = { 'DEFINES_MODULE' => 'YES', 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'i386' }
  s.swift_version = '5.0'
end

See the s.platform = :ios, '11.0'? So I changed the value in my Podfile from 10 to 11 and suddenly, pod install started working again!

Unfortunately, during compilation, I got the following error:

Parse Issue (Xcode): Module 'file_saver' not found

[my_app]/ios/Runner/GeneratedPluginRegistrant.m:17:8

I found a few posts mentioning the error, and the most likely solution for my case is described here. Since I changed the platform version to 11, I need to do this in the deployment target too.

Indeed, in XCode, it was still set to 10

iOS Deployment Target was still set to 10

And after fixing this, it finally compiled successfully.