What's wrong with signing while using Proguard on this case?

Question

Background

Recently I've made a new app, and when I tried to generate a signed APK, I've noticed a weird behavior:

There was no mapping file anywhere in the project's folder.
When enabling the minimizing flags in the gradle file ("minifyEnabled" and "shrinkResources") , it showed an error:

Error:Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'.

Job failed, see logs for details

The problem

Thing is, I didn't add anything special to the project that might cause the Proguard rules not to work. Everything is used in the default way they were set to be.

Here's the app gradle file (replaced some with "...") :

apply plugin: 'com.android.application'

android {
    signingConfigs {
        config {
            keyAlias '...'
            keyPassword '...'
            storeFile file(...)
            storePassword '...'
        }
    }
    compileSdkVersion 25
    buildToolsVersion "25.0.2"
    defaultConfig {
        applicationId '...'
        minSdkVersion 14
        targetSdkVersion 25
        versionCode 21
        versionName "1.21"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
//        vectorDrawables.useSupportLibrary = true
    }
    packagingOptions {
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE-FIREBASE.txt'
        exclude 'META-INF/LICENSE-FIREBASE_jvm.txt'
    }
    buildTypes {
        release {
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.config

        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }
    productFlavors {
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.android.support:appcompat-v7:25.1.1'
    compile 'com.android.support:design:25.1.1'  
    testCompile 'junit:junit:4.12'
    compile 'com.google.android.gms:play-services-plus:10.2.0'
    compile 'com.google.firebase:firebase-ads:10.2.0'
    ...
}

apply plugin: 'com.google.gms.google-services'

As you can see, it's about the same as the original one.

Here's the project gradle file:

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.0-rc1'
        classpath 'com.google.gms:google-services:3.0.0'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
        maven { url "https://jitpack.io" }
        maven {
            url 'https://dl.bintray.com/baole/maven'
        }
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

Nothing special here either.

What I've tried

I also tried to compare the project with another project I have, which doesn't have any issues with Proguard, but I can't find any special difference between them.

The question

Why doesn't Proguard get to work on the project when I sign the app? What should I do to make the special flags work too?

Down-voted for miss leading title. signing doesn't do anything with pro guard. you would probably face the issue if you enable Proguard on debug builds. — Alpha, Mar 01 '17 at 08:11
@Alpha Signing, by default, does use Proguard. The issue in reality, is that the Proguard rules had a faulty line, which I've copied from one of the libraries I use. All the things I thought that caused the issue were ok. Only the Proguard rules were not. Anyway, I will now update the title. — android developer, Mar 01 '17 at 08:38
@Alpha Sorry and thank you. Just was confused about the reason for this issue, and it turned out I was looking in the wrong places, and had a very simple fix. — android developer, Mar 01 '17 at 09:05

score 1 · Answer 1 · edited May 23 '17 at 12:32

1

Probably some of you dependency in app.gradle are causing this due to failing to import or referencing the classes. You can see the import or reference error before/after "Error:Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'." line. The solution to this problem is NOT to minify such dependencies by modifying proguard-rule like this...

-keep class com.itextpdf.** { *; }
-dontwarn com.itextpdf.**

Here is a similar issue.

edited May 23 '17 at 12:32

Community

1
1

answered Feb 20 '17 at 07:03

MSC

422
5
14

But a very similar project has those enabled without any issues. Plus, even though they are disabled, I can't see the mappings file, which I think means proguard didn't obfuscate at all – android developer Feb 20 '17 at 07:06
ok it was a proguard file issue. I think I've fixed it (the mapping file got created). Can you please tell me if it looks ok to you? – android developer Feb 20 '17 at 18:25
this is correct. and dont forget to upvote if this helped you :) – MSC Feb 21 '17 at 04:58
It didn't help. but since it is similar, I will give it +1. – android developer Feb 21 '17 at 09:52

android developer · Accepted Answer · 2017-02-25T00:22:25.157

0

I've found what's causing it, in the proguard file:

-keep class com.google.android.gms.** {  ; }

And the solution is :

-keep class com.google.android.gms.** {  *; }

edited Feb 25 '17 at 00:22

answered Feb 20 '17 at 18:23

android developer

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What's wrong with signing while using Proguard on this case?

Background

The problem

What I've tried

The question

2 Answers2