#603 Call to default super interface method is broken (StackOverFlowException) (invokespecial)

[Volker Berlin]

I use the version 5.2.1. The follow call to a super interface default method:

@Override
public default <T> T unwrap( Class<T> clazz ) {
    return Bar.super.unwrap( clazz );
}

will result in follow bad code which produce a StackOverFlowException:

@Override
public default <T> T unwrap( Class<T> clazz ) {
    return unwrap( clazz );
}

With the javap disambler it look like:

// before ProGuard
public <t extends="" java="" lang="" object=""> T unwrap(java.lang.Class<t>);
Code:
0: aload_0
1: aload_1
2: invokespecial #1 // InterfaceMethod foo/Bar.unwrap:(Ljava/lang/Class;)Ljava/lang/Object;
5: areturn</t></t>

// after ProGuard
public <t extends="" java="" lang="" object=""> T unwrap(java.lang.Class<t>);
Code:
0: aload_0
1: aload_1
2: invokeinterface #4, 2 // InterfaceMethod foo/Bar.unwrap:(Ljava/lang/Class;)Ljava/lang/Object;
7: areturn</t></t>

[Volker Berlin]

A workaround is the option:
-dontoptimize

[Eric Lafortune]

Thanks for your report. I can't seem to reproduce the issue yet (with a hierarchy of a class, a first interface, and a second interface). Can you provide the complete sample?

[Volker Berlin]

Attached is a full sample with original compiled classes and obfuscated classes.

[Eric Lafortune]

Thanks for the sample. I can see how your processed code is incorrect, but I get correct code with ProGuard 5.2.1 and the following configuration:

-injars  classes
-outjars out.jar
-libraryjars <java.home>/lib/rt.jar

-dontobfuscate

-keep class test.MyTest {
    public static void main(java.lang.String[]);
}

What configuration are you using?

[Volker Berlin]

We use a mix of gradle properties and file settings. in gradle we set:
configuration, printseeds, printmapping, printusage, keepparameternames,
renamesourcefileattribute "SourceFile"
keepattributes "Exceptions,InnerClasses,Deprecated,SourceFile,Signature,Annotation,LineNumberTable,EnclosingMethod"
keeppackagenames "com.inet.**"

In the configuration file we set:
-dontusemixedcaseclassnames
-keep @com.inet.annotations.PublicApi class * { public *; }

And a long list of other keep settings.

[Petar Tahchiev]

Hello,

I think i have similar problem. This is my code:

@Transactional
@Override
public void importClasspathResource(@Nonnull String importId, @Nonnull String uri) throws CsvException {
    CsvInputProcessor.super.importClasspathResource(importId, uri);
}

and it gets obfuscated to this:

@Transactional
public void importClasspathResource(@Nonnull String importId, @Nonnull String uri) throws CsvException {
    this.importClasspathResource(importId, uri);
}

notice the call to the super default method is replaced to this method.

How can I add make it work?

[Petar Tahchiev]

And I confirm that adding -dontoptimize works, but is this the real solution, or just a workaround?