[GEODE-9333] SessionsAndCrashesDUnitTest.sessionOperationsDoNotFail_whileServersAreRestarted may fail due to IndexOutOfBoundsException

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.15.0
• Fix Version/s: 1.15.0
• Component/s: redis
• Labels: testing
• Assignee: Jens Deppe
• Reporter: Donal Evans
• Created: 27/May/21 23:28
• Updated: 22/Jun/22 20:46
• Resolved: 04/Jun/21 13:24

Description

Seen in a PR pre-checkin test run:

org.apache.geode.redis.session.SessionsAndCrashesDUnitTest > sessionOperationsDoNotFail_whileServersAreRestarted FAILED
    java.lang.IndexOutOfBoundsException: Index -5 out of bounds for length 100
        at jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:64)
        at jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:70)
        at jdk.internal.util.Preconditions.checkIndex(Preconditions.java:248)
        at java.util.Objects.checkIndex(Objects.java:372)
        at java.util.ArrayList.get(ArrayList.java:459)
        at org.apache.geode.redis.session.SessionsAndCrashesDUnitTest.validateSessionAttributes(SessionsAndCrashesDUnitTest.java:179)
        at org.apache.geode.redis.session.SessionsAndCrashesDUnitTest.sessionOperationsDoNotFail_whileServersAreRestarted(SessionsAndCrashesDUnitTest.java:170)

This occurs in the below block when totalUpdates is less than NUM_SESSIONS.

for (int i = totalUpdates - NUM_SESSIONS; i < totalUpdates; i++) {
  int sessionIdx = i % NUM_SESSIONS;
  String sessionId = sessionIds.get(sessionIdx);
...

Running the test locally with some trace logging added, it seems that totalUpdates is typically ~120, so if something were to cause updates to be 20% slower on a run of the test, this failure could show up. A solution might be to either await until at least NUM_SESSIONS updates have been performed by the updater threads, or to put in some logic to handle the case when totalUpdates is less than NUM_SESSIONS.