IssueTracker

Versions

• r8 version: R8 main (build engineering)
• art version: ART version 2.1.0 x86_64
• java version: 17.0.12

Description

The testcase is a piece of code that appends content to a null string. When processed with D8 and executed using ART, ART correctly reports a java.lang.NullPointerException, consistent with the behavior when executed directly using the JVM. However, after processing the code with R8 to generate a dex file, no error is reported when executed on ART. Upon inspecting the generated dex file using JADX, we found that R8 completely removed the function's content, leaving the body of the main function empty. Could this be considered an issue with R8?

Step to Reproduce

1. javac -source 8 -target 8 -cp . Test.java
2. jar cvf classes.jar ./*.class
3. java -cp r8.jar com.android.tools.r8.R8 --pg-conf rules.pro --release --output ./ ./classes.jar
4. env ANDROID_LOG_TAGS=*:f ANDROID_DATA=./ path-to-art/art --64 --no-compile -cp ./classes.dex Test

JVM Result

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "java.lang.StringBuilder.append(String)" because "<local1>" is null
	at Test.main(Test.java:4)

D8+ART Result

Exception in thread "main" java.lang.NullPointerException: Attempt to invoke a virtual method on a null object reference
	at Test.main(Test.java:4)

R8+ART Result

Testcase Source Code

class Test {
    public static void main(String[] strArr) {
        StringBuilder b = null;
        b.append("0900");
    }
}

rules.pro

-libraryjars android.jar
-keep class Test { public main(java.lang.String[]); }