Do not include unused library to release apk - android

I'm use in my android project gson library:
compile 'com.google.code.gson:gson:2.7'
I'm use it not in app module, but in my android library and this library added to project. Only several classes (groupA) used gson. Android library is common library and used in several android projects, but in current android project do not used classes from groupA.
I have in build.gradle of app:
android {
...
buildTypes {
release {
minifyEnabled true
shrinkResources true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
I build release apk and decompile classes.dex. I do not find classes groupA in apk. It's ok. proguard remove unused code.
Unfortunately I see gson classes. But why? Why proguard do not remove gson classes? gson really do not used in release version of project.

I think you should have a look at the proguard file of gson which is included in each build: https://github.com/google/gson/blob/master/examples/android-proguard-example/proguard.cfg Recognize the remaining classes there?

Why proguard do not remove gson classes?
Ask it:
Use the proguard option -whyareyoukeeping to find out why the gson classes are not removed
http://proguard.sourceforge.net/manual/usage.html#shrinkingoptions

Related

Using Common Proguard File in Multi-Application-Module Android Project

I have created a Wear OS module in our existing Android mobile application. Both application modules remain in the project like following:
Project/app
Project/wear/wear_presentation
Project/otherLibModule/other_lib_module_presentation
and we have a common.gradle that is used by app and wear_presentation:
buildTypes {
release {
minifyEnabled true
debuggable false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
debug {
debuggable true
minifyEnabled false
}
}
Before Wear OS module, we had a single proguard file inside app module that handles all minifying work, but now we have 2 application modules that have separate proguard files. That forces me to copy/paste all content from app proguard file into wear_presentation proguard file and this approach seems amateurish.
I want to use a single common proguard file that is used by both app and wear_presentation modules.
Is it possible?
Importing from Libraries is supported already.
https://developer.android.com/studio/build/shrink-code#configuration-files
/proguard.txt - If an AAR library is published with its own ProGuard rules file, and you include that AAR as a compile-time dependency, R8 automatically applies its rules when compiling your project.
Using rules files that are packaged with AAR libraries is useful if certain keep rules are required for the library to function properly—that is, the library developer has performed the troubleshooting steps for you.
However, you should be aware that, because ProGuard rules are additive, certain rules that an AAR library dependency includes cannot be removed and might impact the compilation of other parts of your app. For example, if a library includes a rule to disable code optimizations, that rule disables optimizations for your entire project.
/META-INF/proguard/ - for JAR libraries
It's commonly used by libraries like OkHttp https://github.com/square/okhttp/blob/okhttp_4.10.x/okhttp/src/main/resources/META-INF/proguard/okhttp3.pro

Configure proguard in a multimodule SDK Android library project

I'm working on an Android SDK that is about to be split into separate modules, with some code being shared between others, namely:
shared classes
SDK with feature #1
SDK with feature #2
There is a need of obfuscating the output AARs. With one single module it's not an issue, but I can't find how to configure the whole project correctly with Proguard.
How does the Proguard obfuscation work in case when I want to publish a new version of all these libraries? Will all the modules be obfuscated separately? How can I make sure that all the modules will be obfuscated at once and the release version of the libraries will correctly refer to all the artifacts that are located in the shared module?
Not sure I understand the issue.
But if you want to release 2 SDKs now instead of 1 (before split), I don't think the setup should differ very much.
Just make sure you have proguard file in these SDKs and you are using it in the build script specific to that SDK (module). Then just run something like :sdk:assembleRelease and you are done.
release {
minifyEnabled true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'library.pro'
}
It is described in detail in this issue:
Obfuscating the .aar files
I understand that shared module is not published, so there you just need to define specific proguard rules that will be used by other modules, like this:
release {
minifyEnabled true
consumerProguardFiles 'onboarding-proguard-rules.pro'
}

How to do proguard for my library (AAR)

I am developing one android library for that i want enable the progurad.
First thing i did is:
I have enabled the minification for my library
buildTypes {
release {
minifyEnabled true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
After this, I have generated the AAR file with minification. And then i used the AAR file to my testing app to check whether my library classes were available. But classes were not there, Because the pro guard removed all my classes from library as it was not used.
Second thing i did is:
-keep public interface com.example.client.** { *; }
I have added the above thing to my proguard-rules.pro. Now i can able to see all my classes with proguard applying the same class, function, variable names. (In mapping file i could see the same name getting applied)
I don't know the exact way to apply the proguard to generate the obfuscated AAR.
Is there any guideline to generate AAR with the minification/
Or in my case what is fix to generate AAR with the class available?
I am struggling for a long time... Could someone please try to help me!!!

How can I build an .aar library with shrunk classes in Android Studio?

I want to build an .aar library and proguard classes, but my library proguard file doesn't work, and I can see clear classes.
Here is my proguard file:
android {
buildTypes {
release {
minifyEnabled true
useProguard true
proguardFiles getDefaultProguardFile('proguard-android.txt'),'proguard-rules-my-lib.pro'
}
}
}
and app/build.gradle:
android {
buildTypes {
release {
minifyEnabled true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
While you can probably shrink and obfuscate the library itself, the usual practice is to leave minifyEnabled as false and provide the proguard configuration to the application, using consumerProguardFiles instead of proguardFiles.
This means that the minification is applied only once, on the whole application, using the merged configuration from the app's proguardFiles and the libraries consumerProguardFiles. This is usually more efficient because parts of the libraries not actually used by the application can be removed.
Create a Android Studio Project and convert it to library Follow this link. Build and Execute the command Generate APK, .aar file will be created in release/debug folder.
Write the proguard rules as similar to APK, it will apply to .aar file also.
I hope this helps

Gradle - Are proguard configurations inherited?

This might be too broad, but I would like an explanation on how Proguard and minification configurations are passed between projects and their dependencies to understand how deeply are these operations made in my project's dependency tree.
I have on build.gradle of `themodule':
buildTypes {
release {
minifyEnabled true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
dependencies {
compile project(':someothermodule')
compile 'some.maven.central.library'
}
By the configuration it seems clear that the classes inside themodule will be minifyed and obfuscated, but what happens with the classes of someothermodule? Will they also be minifyed and obfuscated? Even if someothermodule has minifyEnabled true?
What happens if 'someothermodule' is just a .jar dependency?
What happens with the configurations of some.maven.central.library?
Are the Proguard configurations of the module being built cascading down to its dependencies or each of them follows its own rules?
If a module get obfuscated (minifyEnabled true) by itself, the used configuration is not automatically inherited by the consuming module (in your case the application).
There is a mechanism in the Android gradle plugin to enabled this:
consumerProguardFiles 'proguard-rules.pro'
The rules that are contained in proguard-rules.pro will be automatically included in the application project and merged with other configuration files.
This will only work for Android library projects (.aar). If you have a dependency to a .jar file on maven central for example, no such consumer rules will be available, and you have to add the needed configuration to your application project yourself.
Keep in mind that the configuration to obfuscate a module and the one used by the consuming application / module does not need to be identical. The consumer rules will in most cases only be a set of -keep rules.
Technically, it is the following :
Library projects by themselves don't run ProGuard, so they don't use
any configuration.
Application projects obfuscate the entire code base, including any
referenced libraries, so they need proper configuration for the
application code and for the library code.
I had a small case where I had a Facebook library as a gradle dependency and since we were obfuscating the code with minifyEnabled:true we had to keep all its code from being obfuscated, using the regular keep commmands such as :
-keep class com.facebook.** { *; }
Additionally, and regarding the .jar obfuscation, you can check this other post
Regards,

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