okhttp3 minifyEnabled 导致 Android 4.1.2 崩溃

Question

This code in okhttp:3.12.13 works fine with minifyEnabled false

  private static boolean supportsAlpn() {
    if (Security.getProvider("GMSCore_OpenSSL") != null) {
      return true;
    } else {
      try {
        Class.forName("android.net.Network"); //NoClassDefFoundError here if minifyEnabled true
        return true;
      } catch (ClassNotFoundException ignored) { }
    }
    return false;
  }

but with minifyEnabled true the following error occurs on Android 4.1.2

Caused by: java.lang.ExceptionInInitializerError
    at okhttp3.OkHttpClient.newSslSocketFactory(OkHttpClient.java:292)
    at okhttp3.OkHttpClient.<init>(OkHttpClient.java:258)
    at okhttp3.OkHttpClient.<init>(OkHttpClient.java:231)
Caused by: java.lang.ExceptionInInitializerError
    at java.lang.Class.classForName(Native Method)
    at java.lang.Class.forName(Class.java:217)
    at java.lang.Class.forName(Class.java:172)
    at okhttp3.internal.platform.AndroidPlatform.supportsAlpn(AndroidPlatform.java:219)
    at okhttp3.internal.platform.AndroidPlatform.buildIfSupported(AndroidPlatform.java:262)
    at okhttp3.internal.platform.Platform.findAndroidPlatform(Platform.java:246)
    at okhttp3.internal.platform.Platform.findPlatform(Platform.java:202)
    at okhttp3.internal.platform.Platform.<clinit>(Platform.java:78)
Caused by: java.lang.NoClassDefFoundError
    at android.net.Network.<clinit>(Unknown Source)

What lines should be added to Proguard to avoid the crash?

Edit: Adding rules 1 and 2 didn't help.

These rules worked, but apk size gets increased by 0.6 MB.

-keepattributes Signature
-keepattributes *Annotation*
-keep class okhttp3.** { *; }
-keep interface okhttp3.** { *; }
-dontwarn okhttp3.**

I'm wondering if it is possible to fix the issue without keeping all okhttp3 classes in the apk.

Answer 1

Just get rules from below files/links

https://raw.githubusercontent.com/square/okhttp/master/okhttp/src/jvmMain/resources/META-INF/proguard/okhttp3.pro https://github.com/square/okio/blob/master/okio/src/jvmMain/resources/META-INF/proguard/okio.pro

Refer https://square.github.io/okhttp/features/r8_proguard/