Develop Reference

Proguard failing with 25.1.6 release of Android tools

I downloaded the 25.1.6 release of Android tools today and I'm noticing that proguard is falling over with this error:
Error:Execution failed for task ':app:transformClassesWithNewClassShrinkerForDebug'.
> /usr/local/opt/android-sdk/tools/proguard/proguard-android.txt line 43:15 extraneous input '[]' expecting ')'
I'm certain that I've not changed anything in the proguard-android.txt file. Line 43 reads for me as follows:
void set*(%[]);
I'm noticing that the file here...
https://android.googlesource.com/platform/sdk/+/android-6.0.1_r43/files/proguard-android.txt
... is different to what I have on my machine? Is that file the latest version of the file that I should have?

Just to know several options:
The thing that helped me is replacing corresponding proguard-android.txt file with the one from this page
And just in case the page goes away saving its content here:
# This is a configuration file for ProGuard.
# http://proguard.sourceforge.net/index.html#manual/usage.html
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-verbose
# Optimization is turned off by default. Dex does not like code run
# through the ProGuard optimize and preverify steps (and performs some
# of these optimizations on its own).
-dontoptimize
-dontpreverify
# Note that if you want to enable optimization, you cannot just
# include optimization flags in your own project configuration file;
# instead you will need to point to the
# "proguard-android-optimize.txt" file instead of this one from your
# project.properties file.
-keepattributes *Annotation*
-keep public class com.google.vending.licensing.ILicensingService
-keep public class com.android.vending.licensing.ILicensingService
# For native methods, see http://proguard.sourceforge.net/manual/examples.html#native
-keepclasseswithmembernames class * {
native <methods>;
}
# keep setters in Views so that animations can still work.
# see http://proguard.sourceforge.net/manual/examples.html#beans
-keepclassmembers public class * extends android.view.View {
void set*(***);
*** get*();
}
# We want to keep methods in Activity that could be used in the XML attribute onClick
-keepclassmembers class * extends android.app.Activity {
public void *(android.view.View);
}
# For enumeration classes, see http://proguard.sourceforge.net/manual/examples.html#enumerations
-keepclassmembers enum * {
public static **[] values();
public static ** valueOf(java.lang.String);
}
-keepclassmembers class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator CREATOR;
}
-keepclassmembers class **.R$* {
public static <fields>;
}
# The support library contains references to newer platform versions.
# Don't warn about those in case this app is linking against an older
# platform version. We know about them, and they are safe.
-dontwarn android.support.**

Hmm, it looks the tools/proguard folder in my local copy of the Android SDK is not updated by the Android SDK Manager. I just downloaded the Android SDK afresh from here...
http://developer.android.com/sdk/index.html
... and replaced the tools/proguard folder in that distribution over the tools/proguard in my local copy of the Android SDK and the error's gone.
Would be great if the tools/proguard folder was updated via the Android SDK Manager.

Seems that's happening to some of us. I downloaded just the folder attached in this answer and copied it to android-sdk/tools folder overwriting what's there and now it works without problems.
https://code.google.com/p/android/issues/detail?id=210012

In debug mode I set minifyEnabled to false

Native crashes on some devices with ProGuard

EDIT: For future devs who may be suffering from the same issues, I'm afraid I can't be of much use. The problem apparently solved itself during future versions of the app, but I have been unable to ascertain the cause.
I've been testing an application through the Google Play closed beta testing system, using my friends as beta testers. After pushing an update where the .apk was obfuscated using ProGuard, two testers started reporting crashes. The crashes are unpredictable and sporadic, and they have been unable to ascertain any reason or pattern for them. To make things worse, the crash reports I'm getting in the Dev Console contain no information at all, simply stating "Native crash at (no location available)", no stack trace, not even any device information.
I do know the device information through just asking the testers in question, and both devices are Sony phones, an Xperia Z3 and an Xperia Z3 Compact. However, I also have a Z3 Compact available for testing and have been unable to reproduce the crash while running the same obfuscated apk. We are running the same OS version as well.
I have sent one of the testers and unobfuscated apk, and he was unable to reproduce the crash running that version. This, and the fact that the crash first occurred after a patch that introduced ProGuard obfuscation, leads me to believe that to be the cause.
At first, I ran ProGuard using only the default configuration file from the SDK:
# This is a configuration file for ProGuard.
# LINK REMOVED
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-verbose
# Optimization is turned off by default. Dex does not like code run
# through the ProGuard optimize and preverify steps (and performs some
# of these optimizations on its own).
-dontoptimize
-dontpreverify
# Note that if you want to enable optimization, you cannot just
# include optimization flags in your own project configuration file;
# instead you will need to point to the
# "proguard-android-optimize.txt" file instead of this one from your
# project.properties file.
-keepattributes *Annotation*
-keep public class com.google.vending.licensing.ILicensingService
-keep public class com.android.vending.licensing.ILicensingService
# For native methods, see LINK REMOVED
-keepclasseswithmembernames class * {
native <methods>;
}
# keep setters in Views so that animations can still work.
# see http://proguard.sourceforge.net/manual/examples.html#beans
-keepclassmembers public class * extends android.view.View {
void set*(***);
*** get*();
}
# We want to keep methods in Activity that could be used in the XML attribute onClick
-keepclassmembers class * extends android.app.Activity {
public void *(android.view.View);
}
# For enumeration classes, see http://proguard.sourceforge.net/manual/examples.html#enumerations
-keepclassmembers enum * {
public static **[] values();
public static ** valueOf(java.lang.String);
}
-keepclassmembers class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator CREATOR;
}
-keepclassmembers class **.R$* {
public static <fields>;
}
# The support library contains references to newer platform versions.
# Don't warn about those in case this app is linking against an older
# platform version. We know about them, and they are safe.
-dontwarn android.support.**
I have since added the following lines to proguard-project.txt, which is also included in the proguard configuration variable for the project:
-keep class * extends java.util.ListResourceBundle {
protected java.lang.Object[][] getContents();
}
# Keep SafeParcelable value, needed for reflection. This is required to support backwards
# compatibility of some classes.
-keep public class com.google.android.gms.common.internal.safeparcel.SafeParcelable {
public static final *** NULL;
}
# Keep the names of classes/members we need for client functionality.
-keepnames #com.google.android.gms.common.annotation.KeepName class *
-keepclassmembernames class * {
#com.google.android.gms.common.annotation.KeepName *;
}
# Needed for Parcelable/SafeParcelable Creators to not get stripped
-keepnames class * implements android.os.Parcelable {
public static final ** CREATOR;
}
# Needed when building against the Marshmallow SDK
-dontwarn org.apache.http.**
# Needed when building against pre-Marshmallow SDK.
-dontwarn android.security.NetworkSecurityPolicy
-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.BroadcastReceiver
-keep public class * extends android.content.ContentProvider
-libraryjars D:/Docs/Android/spaceprog/spaceprogr/libs/android-support-v4.jar
-keep class com.viewpagerindicator.** { *; }
-keep class com.google.android.gms.** { *; }
-keep class com.google.example.games.basegameutils.** { *; }
-printmapping out.map
-renamesourcefileattribute SourceFile
-keepattributes SourceFile,LineNumberTable
The upper part (with comments) of these additions comes directly from the README of the Google Play Services as a recommendation to be added whenever using the library. The rest I added myself while trying to research and debug the problem.
If anyone notices any omissions or other signs of trouble in my ProGuard configuration I'd be happy to know. I'd also be greatful for any suggestions on how to further debug the problem. Keep in mind that full module testing where only one module is obfuscated at a time is impossible in this case, because I do not have a device that can reproduce the issue and I cannot ask volunteer testers to install 30+ different versions of the .apk and play until it either crashes or until they are confident it will not.

Proguard and Netty 5 on Android

I've seen a couple questions regarding this issue, but they are for older versions of Netty.
I have tried their answers, switching org.jboss.netty out with io.netty, but the same error occurs.
I'm trying to compile an Android app that uses Netty 5.0.0Alpha2 (build #16) with Proguard enabled.
Without Proguard, the app runs fine.
As soon as I enable Proguard, I get this exception when it tries to use Netty:
java.lang.IllegalStateException: unknown type parameter 'I': class io.netty.channel.SimpleChannelInboundHandler
at io.netty.util.internal.TypeParameterMatcher.find0(Unknown Source)
at io.netty.util.internal.TypeParameterMatcher.find(Unknown Source)
at io.netty.channel.SimpleChannelInboundHandler.<init>(Unknown Source)
at io.netty.channel.SimpleChannelInboundHandler.<init>(Unknown Source)
...
This is my Proguard config:
# billing
-keep class com.android.vending.billing.**
# butterknife
-dontwarn butterknife.internal.**
-keep class **$$ViewInjector {
*;
}
-keepnames class * {
#butterknife.InjectView *;
}
# admob
-keep public class com.google.android.gms.ads.** {
public *;
}
-keep public class com.google.ads.** {
public *;
}
# logging
-assumenosideeffects class android.util.Log
# netty (partial)
-dontwarn io.netty.**
-dontwarn sun.**
I have tested it without the -dontwarn options to see if the warnings would point me in the right direction, but it's all missing optional dependencies like slf4j and Tomcat.
I have also tried excluding all the Netty classes like so:
-keep class io.netty.** {
*;
}
...but that does not appear to fix it either.

I have fixed this issue with some carefully* applied Proguard rules after reading through parts of the rather huge Netty sources:
-keepattributes Signature,InnerClasses
-keepclasseswithmembers class io.netty.** {
*;
}
-keepnames class io.netty.** {
*;
}
My original exception was caused by the type variables being removed from the bytecode, which Netty uses via reflection. Signature in -keepattributes keeps this information.
You get a slightly different exception if you only do Signature on -keepattributes - adding InnerClasses fixes this one by bringing back even more information in the class files.
Later, I got java.lang.NoSuchFieldException: ctl; that's what -keepnames is for. This way, the field is still called ctl like Netty expects.
Finally, some members (like ctl, seen earlier) were being removed by Proguard because Netty only uses them via reflection. The final rule, -keepclasseswithmembers, makes sure Proguard doesn't remove them.
If you take this approach, I strongly recommend you use only the Netty jars you need, instead of the -all jar. Switching from -all to just the required Netty jars brought my method count way down after I had gone past the 65k limit. Reducing your jars requires bit of trial-and-error though as the separation is unclear and there's not really any resources saying what's what.
* not carefully at all, I just slapped rules into the file and removed them if they did nothing. There's probably a better way to do this that doesn't keep this information in the entire program, but instead just Netty.

Una's answer keep too many classes, which makes my app 1MB larger than usual. So I use the rules below:
# netty
-keepclassmembernames class io.netty.buffer.AbstractByteBufAllocator {
*;
}
-keepclassmembernames class io.netty.buffer.AdvancedLeakAwareByteBuf {
*;
}
-keep public class io.netty.util.ReferenceCountUtil {
*;
}

Does Proguard remove comments from Java source

I am using the code from proguard-android.txt file below
# This is a configuration file for ProGuard.
# http://proguard.sourceforge.net/index.html#manual/usage.html
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-verbose
# Optimization is turned off by default. Dex does not like code run
# through the ProGuard optimize and preverify steps (and performs some
# of these optimizations on its own).
-dontoptimize
-dontpreverify
# Note that if you want to enable optimization, you cannot just
# include optimization flags in your own project configuration file;
# instead you will need to point to the
# "proguard-android-optimize.txt" file instead of this one from your
# project.properties file.
-keepattributes *Annotation*
-keep public class com.google.vending.licensing.ILicensingService
-keep public class com.android.vending.licensing.ILicensingService
# For native methods, see http://proguard.sourceforge.net/manual/examples.html#native
-keepclasseswithmembernames class * {
native <methods>;
}
# keep setters in Views so that animations can still work.
# see http://proguard.sourceforge.net/manual/examples.html#beans
-keepclassmembers public class * extends android.view.View {
void set*(***);
*** get*();
}
# We want to keep methods in Activity that could be used in the XML attribute onClick
-keepclassmembers class * extends android.app.Activity {
public void *(android.view.View);
}
# For enumeration classes, see http://proguard.sourceforge.net/manual/examples.html#enumerations
-keepclassmembers enum * {
public static **[] values();
public static ** valueOf(java.lang.String);
}
-keep class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator *;
}
-keepclassmembers class **.R$* {
public static <fields>;
}
# The support library contains references to newer platform versions.
# Don't warn about those in case this app is linking against an older
# platform version. We know about them, and they are safe.
-dontwarn android.support.**
to obfuscate Android code.
My Question Does Proguard remove all the comments from the Java source file when we use the above settings in Proguard?

ProGuard doesn't remove anything from the source files, regardless of settings. ProGuard makes sure that the compiled files have obfuscated method/class names and strips appropriate methods/classes completely when possible.
Compiled Java binaries don't include regular code comments whether you're using ProGuard or not.

Proguard and XStream with omitField() on Android

I was using XStream for deserialization of xml in my Android app, and now I'm struggling to add Proguard (obfuscator) to the mix.
Here's the runtime exception I run into (full: pastebin):
WARN/System.err(6209): net.lp.collectionista.util.a.g: XStream could not parse the response
WARN/System.err(6209): at net.lp.collectionista.a.s.a(Collectionista:215)
...
WARN/System.err(6209): Caused by: com.thoughtworks.xstream.converters.ConversionException: id : id in loader dalvik.system.PathClassLoader[/data/app/net.lp.collectionista-2.apk] : id : id in loader dalvik.system.PathClassLoader[/data/app/net.lp.collectionista-2.apk]
WARN/System.err(6209): ---- Debugging information ----
WARN/System.err(6209): message : id : id in loader dalvik.system.PathClassLoader[/data/app/net.lp.collectionista-2.apk]
WARN/System.err(6209): cause-exception : com.thoughtworks.xstream.mapper.CannotResolveClassException
WARN/System.err(6209): cause-message : id : id in loader dalvik.system.PathClassLoader[/data/app/net.lp.collectionista-2.apk]
WARN/System.err(6209): class : net.lp.collectionista.jaxb.googlebooks.search.Feed
WARN/System.err(6209): required-type : java.lang.Object
WARN/System.err(6209): path : /feed/entry/id
WARN/System.err(6209): line number : 1
WARN/System.err(6209): -------------------------------
WARN/System.err(6209): at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(Collectionista:89)
...
WARN/System.err(6209): at com.thoughtworks.xstream.XStream.fromXML(Collectionista:861)
...
WARN/System.err(6209): Caused by: com.thoughtworks.xstream.mapper.CannotResolveClassException: id : id in loader dalvik.system.PathClassLoader[/data/app/net.lp.collectionista-2.apk]
WARN/System.err(6209): at com.thoughtworks.xstream.mapper.DefaultMapper.realClass(Collectionista:68)
...
Needless to say this works fine without Proguard. I'm using shrinking, optimizing and obfuscating here, though I disabled it all on any XStream class, as well as any class that stands model for the xml fields:
-keep class net.lp.collectionista.jaxb.** { *; }
-keep class com.thoughtworks.xstream.** { *; }
I can confirm, from the obfuscated jar, as well as from the mapping.txt (for methods), that any classes mentioned exist and are not obfuscated, so untouched AFAICT. I also am retaining annotations.
The exception is pretty clear to me. I have:
xstream.omitField(Feed.class, "id");
among others. It seems the omitField() call does not work anymore and it starts looking for an "id" model class, because of Proguard. This is where I am stuck, even after diving into the XStream code. The whole omitField call in the obfuscated end result seems to be intact, so what could be additionally broken here? It should also not be "Feed.class" as that one is also still there. What am I missing? What is a good next step for debugging?
EDIT: I did notice the class files of xstream classes in my obfuscated jar are slightly smaller than the original ones, even with -dontoptimize. What is still being dropped?
EDIT2: I'm starting to think it has to do with the absence of dex warnings similar to the following:
[apply] warning: Ignoring InnerClasses attribute for an anonymous inner class
[apply] (com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter$1) that doesn't come with an
[apply] associated EnclosingMethod attribute. This class was probably produced by a
[apply] compiler that did not target the modern .class file format. The recommended
[apply] solution is to recompile the class from source, using an up-to-date compiler
[apply] and without specifying any "-target" type options. The consequence of ignoring
[apply] this warning is that reflective operations on this class will incorrectly
[apply] indicate that it is *not* an inner class.
... or maybe not ...
EDIT3: Finally, in spite of dealing with many other bugs and problems such as the SimException bug, I've been able to get it working in some limited cases. That way I could pinpoint it to the obfuscation step. That is, at least, if I add "-dontobfuscate", the problem goes away. it isn't the first time I'm playing with that, so it must be the workarounds for the other problems, or the narrower configuration, that alleviates this problem as well. So here's me asking again: When I've already safeguarded the main parts of xstream and my model classes from obfuscation using "-keep", then what else could be creating this mess?
If you need more info, let me know.

As I said, the problem disappears if you -dontobfuscate but let's suppose you don't want that.
The solution is to keep more attributes:
-keepattributes EnclosingMethod, InnerClasses
-keepattributes *Annotation*
-keepattributes Signature
Once you get it working you can narrow down which parts of the XStream code to keep as well. I have:
-keep class com.thoughtworks.xstream.converters.extended.SubjectConverter { *; }
-keep class com.thoughtworks.xstream.converters.extended.ThrowableConverter { *; }
-keep class com.thoughtworks.xstream.converters.extended.StackTraceElementConverter { *; }
-keep class com.thoughtworks.xstream.converters.extended.CurrencyConverter { *; }
-keep class com.thoughtworks.xstream.converters.extended.RegexPatternConverter { *; }
-keep class com.thoughtworks.xstream.converters.extended.CharsetConverter { *; }
-keep class com.thoughtworks.xstream.annotations.** { *; }
You can also disable a lot of warnings related to XStream.
For more details you can find my version controlled project files here:
proguard.cfg
build.xml

I seem to be one of many to have problems with ProGuard and XStream for Android. After some trial and research, the following is what works for me - a complete config file together with some explanatory comments why I did what I did. Note that my priority was to obfuscate, but I did not care much about optimizing or shrinking.
And you need to remember that with this config (which keeps public members for libraries - see below) you will need to use "public" members for the class that is used by XStream to create your XML, because XStream will use member names for XML labels - and you do not want your XML labels to be changed to "a", "b" or "c" :) Good luck!
###########################################################
#
# FLAGS
#
###########################################################
# Not sure if I need this one, but seems to do no harm
-keepdirectories
# I needed NOT to optimize for SWT or XStream would not work, but for Android I do not seem to need to do that.
# However, if I try to shrink, XStream fails for Android. This different behaviour is a bit odd and black magic.
# However, I do not much care about optimization or size, and stability is more important for me, so let's
# neither optimize nor shrink (and shrinking saved us only about 1.5% of the size anyway).
#
# Note: this was not all that was necessary to make XStream run for Android - see other comments
# (search for XStream)
-dontshrink
-dontoptimize
# The following was configured for Android by default but now it does not make sense because I do not optmize, so disable just in case.
# -optimizationpasses 5
# Not sure if I need this one, but seems to do no harm.
-keeppackagenames
# This was configured for Android by default and it can only help.
-dontusemixedcaseclassnames
# This was configured for Android by default, and it is the default option as of ProGuard 4.5 anyway.
-dontskipnonpubliclibraryclasses
# ProGuard documentation says:
# For Java 6, preverification is optional, but as of Java 7, it is required.
# Only when eventually targeting Android, it is not necessary, so you can then
# switch it off to reduce the processing time a bit.
-dontpreverify
# Specifies to write out some more information during processing. If the
# program terminates with an exception, this option will print out the
# entire stack trace, instead of just the exception message.
-verbose
# Since I have turned off optmization, it makes no sense to have the following
# option enabled.
#-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*
# The followig was necessary or it would not build, as it otherwise wants a totally clean build first.
-ignorewarnings
###########################################################
#
# -keep SPECIFICATIONS
#
###########################################################
# I tried adding those to fix the XStream problem, but in the end fixed it differently (see other comments).
#-keepattributes EnclosingMethod, InnerClasses
#-keepattributes *Annotation*
#-keepattributes Signature
# The following was configured for Android by default.
-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.BroadcastReceiver
-keep public class * extends android.content.ContentProvider
-keep public class * extends android.app.backup.BackupAgentHelper
-keep public class * extends android.preference.Preference
-keep public class com.android.vending.licensing.ILicensingService
# I tried adding those to fix the XStream problem, but in the end fixed it differently (see other comments).
# However, it might still be a good idea to stay away from thoughtworks for stability's sake.
# (Not sure if the second keep does not include the first one.)
-keep class com.thoughtworks.xstream.*
-keep class com.thoughtworks.xstream.* {
public protected <methods>;
public protected <fields>;
}
# The following plus not-shrinking seems necessary to make XStream run for Android.
# But again, as for SWT, I did not need to exclude all, public and protected methods and fields:
# just doing the public fields was enough.
# public protected <methods>;
# public protected <fields>;
-keep public class * {
public <fields>;
}
# This was configured for Android by default - and very necessary it is too.
-keepclassmembers enum * {
public static **[] values();
public static ** valueOf(java.lang.String);
}
# I put it in because we might need this one in the future.
# This was default for the Windows installation of ProGuard, which said:
# Also keep - Database drivers. Keep all implementations of java.sql.Driver.
-keep class * extends java.sql.Driver
# This was configured for Android by default.
-keepclasseswithmembernames class * {
native <methods>;
}
# This was configured for Android by default.
-keepclasseswithmembers class * {
public <init>(android.content.Context, android.util.AttributeSet);
}
# This was configured for Android by default.
-keepclasseswithmembers class * {
public <init>(android.content.Context, android.util.AttributeSet, int);
}
# This was configured for Android by default.
-keepclassmembers class * extends android.app.Activity {
public void *(android.view.View);
}
# This was configured for Android by default.
-keep class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator *;
}

XStream seems to introspect on the EnclosingMethod attribute, so keeping it in your ProGuard configuration may help:
-keepattributes EnclosingMethod
The ProGuard manual provides a list of attributes that you may want to keep. The error message suggests that you're already keeping the InnerClasses attribute, which is probably required indeed.