Flutter: Firestore unavailable error on release mode with minifyEnabled

Question

I have been experiencing a very strange error. I have been developing an app for some time now (3 years ago) with flutter. I migrated the application to Null safety and from that moment the app started to crash in release mode causing the error

[cloud_firestore/unavailable] The service is currently unavailable. This is a most likely a transient condition and may be corrected by retrying with a backoff.

Everything works fine on debug mode.

I have the following configuration in the related files in the apk compilation in release mode.

android/build.gradle

buildscript {
    ext.kotlin_version = '1.4.21'
    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:4.1.0'
        classpath 'com.google.gms:google-services:4.3.8'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'com.google.firebase:firebase-crashlytics-gradle:2.7.1'
    }
}

allprojects {
    repositories {
        google()
        jcenter()

    }
}
...

android/app/build.gradle

...
android {

    buildTypes {
        release {
            signingConfig signingConfigs.release
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 
        }
    }
}
...

proguard-rules.pro

## Flutter wrapper
-keep class io.flutter.app.** { *; }
-keep class io.flutter.plugin.**  { *; }
-keep class io.flutter.util.**  { *; }
-keep class io.flutter.view.**  { *; }
-keep class io.flutter.**  { *; }
-keep class io.flutter.plugins.**  { *; }
-keep class com.google.firebase.** { *; }
-keep class com.revenuecat.purchases.** { *; }
-keep class androidx.lifecycle.DefaultLifecycleObserver
-dontwarn android.**

If I change minifyEnabled false shrinkResources false to Everything works fine on release mod too, but my app size increase by 27%.

Answer 1

One thing that may work for you is go back to using proguard instead of R8, it may be a step back but could help you. For that to happen the configuration of the release should look like:

buildTypes {
    release {
        signingConfig signingConfigs.release
        minifyEnabled true
        shrinkResources true
        useProguard true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 
    }
}

And maybe you should add to the build gradle that you don't want to use R8:

android.enableR8=true

Another option would be to look at this file and check for the imports to see if there is maybe a secondary library that you should add to your proguard configuration file: /android/app/src/main/java/io/flutter/plugins/GeneratedPluginRegistrant

You can also check the compilation log to see any errors related to some library (link: https://github.com/flutter/flutter/issues/15100#issuecomment-474687849 )

Answer 2

Have you tried updating to a relatively new version of https://pub.dev/packages/cloud_firestore , eg 2.5.2 currently?

What version are you currently using?

Share your pubspec.yaml, sometimes plugins can conflict too.