ADDITIONAL SYSTEM INFORMATION :
JDK 21ea31

A DESCRIPTION OF THE PROBLEM :
With the fix for JDK-8132995 MatchResult only stores the substring covering the match but does not account for capturing groups outside the match, i.e. within look-behind or look-ahead groups.

The correct behavior would be not only consider the start and end of the match but the minimum start and the maximum end of all capturing groups.

REGRESSION : Last worked in version 20.0.2

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile and run the attached program


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
It should print

match from 3 to 6: ABC
prefix: 123
suffix: 456
match from 3 to 6: ABC
prefix: 123
suffix: 456

ACTUAL -
match from 3 to 6: ABC
prefix: 123
suffix: 456
match from 3 to 6: ABC
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: Range [-3, 0) out of bounds for length 3
        at java.base/jdk.internal.util.Preconditions$1.apply(Preconditions.java:55)
        at java.base/jdk.internal.util.Preconditions$1.apply(Preconditions.java:52)
        at java.base/jdk.internal.util.Preconditions$4.apply(Preconditions.java:213)
        at java.base/jdk.internal.util.Preconditions$4.apply(Preconditions.java:210)
        at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:98)
        at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckFromToIndex(Preconditions.java:112)
        at java.base/jdk.internal.util.Preconditions.checkFromToIndex(Preconditions.java:349)
        at java.base/java.lang.String.checkBoundsBeginEnd(String.java:4861)
        at java.base/java.lang.String.substring(String.java:2830)
        at java.base/java.util.regex.Matcher$ImmutableMatchResult.group(Matcher.java:348)
        at CapturingGroups.printResult(CapturingGroups.java:27)
        at CapturingGroups.main(CapturingGroups.java:21)


---------- BEGIN SOURCE ----------
import java.nio.CharBuffer;
import java.util.Arrays;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class CapturingGroups {
  public static void main(String[] args) {
      char[] data = "123ABC456".toCharArray();
  
      Matcher m = Pattern.compile("(?<=(\\d{3})).*(?=(\\d{3}))").matcher(CharBuffer.wrap(data));
  
      if(!m.find()) throw new AssertionError();
  
      printResult(m);
  
      MatchResult mr = m.toMatchResult();
  
      Arrays.fill(data, '*');
  
      printResult(mr);
  }

  private static void printResult(MatchResult mr) {
      System.out.println("match from " + mr.start() + " to " + mr.end() + ": " + mr.group());
  
      System.out.println("prefix: " + mr.group(1));
      System.out.println("suffix: " + mr.group(2));
  }
}

---------- END SOURCE ----------

FREQUENCY : always