IssueTracker

Versions

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

Description

We discovered a testcase, when executed directly by the JVM, it throws a java.lang.IndexOutOfBoundsException. JVM believes that the contents of the list should not be modified while reading it. In contrast to the JVM's direct execution results, when we run the program processed by R8 using host-art, the output shows 2 without any errors. This is inconsistent with the JVM's implementation. Could this potentially be an issue?

Step to Reproduce

1. javac -source 8 -target 8 -cp . Test.java
2. jar cvf classes.jar ./*.class
3. java -cp d8.jar com.android.tools.r8.D8 --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.IndexOutOfBoundsException: start 0, end 46, length 0
        at java.base/java.lang.AbstractStringBuilder.checkRange(AbstractStringBuilder.java:1802)
        at java.base/java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:680)
        at java.base/java.lang.StringBuilder.append(StringBuilder.java:218)
        at Test.a(Test.java:4)
        at Test.d(Test.java:9)
        at Test.main(Test.java:14)

R8+ART Result

2

Testcase Source Code

class Test {
  public static void main(String[] strArr) {
    java.util.ArrayList numbers = new java.util.ArrayList();
    numbers.add(10);
    numbers.add(20);
    numbers.add(40);
    java.util.Iterator<Integer> iterator = numbers.iterator();
    while (iterator.hasNext())
      if (iterator.next() == 40)
        numbers.remove(2);
    System.out.println(numbers.size());
  }
}

rules.pro

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