Android app crash: Why there is (Unknown Source) instead of line number

Question

My app that I built and signed to publish crashes occasionally on my machine, in the logcat I open the stacktrace for a null pointer exception.. But I am not able locate exact line numbers ? because it say (Unknown Source) for example some lines look like this

   Caused by: java.lang.NullPointerException
   at   me.com.myapplication.a.i.d(Unknown Source)
   at   me.com.myapplication.MainActivity.onResume(Unknown Source)
   at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1210)

As you see where-ever there is my application package I see no line numbers instead it says Unknown Source.

Here is my gradle config for this project.

apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "23.0.2"

defaultConfig {
    applicationId "me.com.myappliaction"
    minSdkVersion 8
    targetSdkVersion 21
    versionCode 6
    versionName "2.0"
}

signingConfigs {
    signed {
        storeFile file('../keystore/my.keystore')
        storePassword 'xxxxxx'
        keyAlias 'xxxxx'
        keyPassword 'xxxxxx'
    }
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }

    signed {
        debuggable false
        minifyEnabled true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        signingConfig signingConfigs.signed
    }

}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.1.1'
compile project(':mycomponent')
}

The app was using signed build variant. I used proguard command to read the trace properly using following syntax

retrace.bat|retrace.sh [-verbose] mapping.txt [<stacktrace_file>]

after this class names are shown better but still no line numbers ? I am wondering what exactly is wrong here that causes line numbers to be missing ?? How can I get trace that shows line numbers in my code and still be able to make it ready for publishing ?

Answer 1

In order to retain debug information after ProGuard builds, you need to add the following configuration (to your proguard-rules.pro file):

-keepattributes SourceFile,LineNumberTable
# rename the source files to something meaningless, but it must be retained
-renamesourcefileattribute ''

Answer 2

This error will occur when you have enabled minify in build.gradle.

minifyEnabled true

To get the line number while using proguard, you have to write following line inside proguard-rules.pro

-keepattributes *Annotation*,SourceFile,LineNumberTable

and you are done.

Answer 3

You also could upload the mapping.txt file to your Google Play Developer Console. On the console just click on the app you want to deobfuscate. Then go to "Android vitals" > "ANRs & Crashes":

https://play.google.com/apps/publish/?dev_acc=[YOUR-DEV_ID]#DeobfuscationMappingFilesPlace:p=[your.app.package]

and upload the mapping.txt file that fits the current version of your app.

Location of mapping.txt:

Android Studio:

\[YOUR-PROJECT-DIR]\app\build\outputs\mapping\release\mapping.txt

Eclipse:

\[ECLIPSE-WORKSPACE]\[YOUR-PROJECT-DIR]\proguard\mapping.txt

Beware: Errors are deobfuscated only AFTER the upload of the mapping.txt. There is no deobfuscation of already reported crashes in the Google Play Developer Console.