Why is minifyEnabled is false in release builds by default?

Question

In build.gradle (app) file we have this by default,

buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
    }
}

According to https://developer.android.com/studio/build/shrink-code,

minifyEnabled true make the code more secure (making it hard to reverse engineer) and also shrink the size in release build, which we use for publishing the app.

I know that using minifyEnabled true makes compile time longer, but usually debug builds are used for development and testing, which is not affected anyways.

What I'm looking for is that, what are the disadvantages (such as performance impacts) cause by using minifyEnabled true at runtime. I'm not worried about the build time of a release build.

Google Play Console also recommending us to enable it therefore I'm wondering why is minifyEnabled is disabled by default.

Answer 1

By adding minifyEnabled true in your release build you can obfuscate code but it is set to false by default in release builds because if set true it shall require proguard rules to be written to tell the compiler which classes are to be ignored while obfuscating the code. If minifyEnabled is set to true by default and the developer forgets to add proguard rules, it can lead to runtime crashes.

However, setting minifyEnabled to true and shrinkResources to true can reduce your apk size.