[CURATOR-663] ZooKeeperServerEmbeddedAdapter.configure might fail with ClassCastException

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 5.4.0
• Fix Version/s: 5.8.0
• Component/s: Framework
• Assignee: Unassigned
• Reporter: Matthias Pohl
• Created: 28/Mar/23 20:15
• Updated: 11/Jun/24 09:57

Description

There might be a ClassCastException happening when starting the TestingZooKeeper instance. The following test reproduces the issue:

@Test
public void testTestingZooKeeperServer() throws Exception
{
  final Map<String, Object> customProperties = new HashMap<>();
  customProperties.put("maxSessionTimeout", 60_000);

  final Path tmpDirPath = Files.createTempDirectory("tmp-");
  final InstanceSpec instanceSpec = new InstanceSpec(tmpDirPath.toFile(), 0, 0, 0, true, 0, 10, 1, customProperties, "host-name");
  final QuorumConfigBuilder quorumConfigBuilder = new QuorumConfigBuilder(instanceSpec);
  final TestingZooKeeperServer zkServer = new TestingZooKeeperServer(quorumConfigBuilder);

  zkServer.start();
}

The test above will fail with a ClassCastException because InstantSpec allows a Map<String, Object> for custom properties, i.e. a non-String value like Integer can be used.

This Map is then passed over into a Properties instance in QuorumConfigBuilder:163. These Properties are then written to a temporary file in ZooKeeper's ZooKeeperServerEmbeddedImpl:58 which expects only to have String values. The previously set Integer value isn't converted to a String anywhere, though.