CASSANDRA-21097: parseGossipInfo improper assumption might fail to parse gossip output after a node restart

[teamconfx]

This PR fix CASSANDRA-21097

Issue

ClusterUtils.parseGossipInfo() threw NullPointerException when parsing gossip info because it only checked for lines starting with "/" to identify endpoint addresses. When InetAddress.getHostName() is called (e.g., by JMX
methods), the hostname gets cached and toString() returns "localhost/127.0.0.1" instead of "/127.0.0.1".

Fix Applied

File: test/distributed/org/apache/cassandra/distributed/shared/ClusterUtils.java

1. Added a regex pattern to match both formats:

  private static final Pattern GOSSIP_ENDPOINT_PATTERN =
      Pattern.compile("^[^\\s/]*/(\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3})(:\\d+)?$");

2. Updated the parsing logic:

  // Before: 
if (line.startsWith("/"))
  // After:  
if (GOSSIP_ENDPOINT_PATTERN.matcher(line).matches())

Test Added

File: test/distributed/org/apache/cassandra/distributed/shared/ClusterUtilsParseGossipInfoTest.java

4 test cases covering:

• Standard /IP:port format
• Hostname prefix localhost/IP:port format
• Mixed formats
• Without port numbers