[core] New enum pattern with anonymous classes adds invalid synthetic constructor/ external vars with dx/d8

[nitram84]

Issue details

I found a new enum pattern currently unhandled in jadx:

Example 1:

package jadx.test;

public enum EnumAnonymous1 {
  TEST {}
}

decompiles to:

package jadx.test;

/* JADX INFO: loaded from: classes.dex */
public enum EnumAnonymous1 {
    TEST { // from class: jadx.test.EnumAnonymous1.1
    };

    /* synthetic */ EnumAnonymous1(AnonymousClass1 x2) {
        this();
    }
}

Example 2: Same with arguments and test w/o DX/D8

package jadx.test;

public enum EnumAnonymous2 {
  TEST1("TEST1", 0) {
  };

  EnumAnonymous2(final String string, final int i) {}
}

without dx/d8 decompiles to:

package jadx.test;

/* JADX INFO: loaded from: jadx/test/EnumAnonymous2.class */
public enum EnumAnonymous2 {
    TEST1("TEST1", 0) { // from class: jadx.test.EnumAnonymous2.1
    };

    /* synthetic */ EnumAnonymous2(String x2, int x3, AnonymousClass1 x4) {
        this(x2, x3);
    }

    EnumAnonymous2(String string, int i) {
    }
}

and with dx/d8 to:

package jadx.test;

/* JADX WARN: Enum visitor error
jadx.core.utils.exceptions.JadxRuntimeException: Init of enum field 'TEST1' uses external variables
	at jadx.core.dex.visitors.EnumVisitor.createEnumFieldByConstructor(EnumVisitor.java:485)
	at jadx.core.dex.visitors.EnumVisitor.processEnumFieldByField(EnumVisitor.java:399)
	at jadx.core.dex.visitors.EnumVisitor.processEnumFieldByWrappedInsn(EnumVisitor.java:364)
	at jadx.core.dex.visitors.EnumVisitor.extractEnumFieldsFromFilledArray(EnumVisitor.java:349)
	at jadx.core.dex.visitors.EnumVisitor.extractEnumFieldsFromInsn(EnumVisitor.java:284)
	at jadx.core.dex.visitors.EnumVisitor.convertToEnum(EnumVisitor.java:153)
	at jadx.core.dex.visitors.EnumVisitor.visit(EnumVisitor.java:102)
 */
/* JADX WARN: Failed to restore enum class, 'enum' modifier and super class removed */
/* JADX INFO: loaded from: classes.dex */
public class EnumAnonymous2 {
    private static final /* synthetic */ EnumAnonymous2[] $VALUES;
    public static final EnumAnonymous2 TEST1;

    /* synthetic */ EnumAnonymous2(String x0, int x1, String x2, int x3, AnonymousClass1 x4) {
        this(x0, x1, x2, x3);
    }

    public static EnumAnonymous2 valueOf(String name) {
        return (EnumAnonymous2) Enum.valueOf(EnumAnonymous2.class, name);
    }

    public static EnumAnonymous2[] values() {
        return (EnumAnonymous2[]) $VALUES.clone();
    }

    static {
        String str = "TEST1";
        int i = 0;
        TEST1 = new EnumAnonymous2(str, i, str, i) { // from class: jadx.test.EnumAnonymous2.1
        };
        $VALUES = new EnumAnonymous2[]{TEST1};
    }

    private EnumAnonymous2(String str, int i, String string, int i2) {
        super(str, i);
    }
}

Relevant log output or stacktrace

no errors logged

Provide sample and class/method full name

See issue details.

Jadx version

1.5.6, latest git

[tejasng053]

Hi! I'd like to work on this issue. I understand that anonymous enum constants can cause JADX to retain an invalid synthetic constructor, and the dx/d8 case can also prevent EnumVisitor from reconstructing the enum because constructor arguments are treated as external variables. I'd like to first add focused regression cases for the examples in this issue, then trace the enum-constructor handling and work toward a minimal fix. Please let me know if there are any implementation details you'd prefer me to consider. Thanks!