[jira] [Commented] (KAFKA-3096) Leader is not set to -1 when it is shutdown if followers are down

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-3096?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16007840#comment-16007840 ] 

ASF GitHub Bot commented on KAFKA-3096:
---------------------------------------

GitHub user ijuma opened a pull request:

    https://github.com/apache/kafka/pull/3031

    MINOR: Fix bug in `waitUntilLeaderIsElectedOrChanged` and simplify result type

    Also disable a couple of tests that were passing incorrectly until KAFKA-3096 is fixed.
    
    The bug was for the following case:
    
    `leader.isDefined && oldLeaderOpt.isEmpty && newLeaderOpt.isDefined && newLeaderOpt.get != leader.get`
    
    We would consider it a successful election even though we should not.
    
    I also changed the result type as we never return `None` (we throw an exception instead).

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/ijuma/kafka fix-wait-until-leader-is-elected

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/kafka/pull/3031.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #3031
    
----
commit 75a441087f4bbac973afe1198fd382df790552f6
Author: Ismael Juma <is...@juma.me.uk>
Date:   2016-01-08T16:48:47Z

    MINOR: Fix bug in `waitUntilLeaderIsElectedOrChanged` and simplify result type
    
    Also disable a couple of tests that were passing incorrectly until KAFKA-3096 is fixed.
    
    The bug was for the following case:
    
    `leader.isDefined && oldLeaderOpt.isEmpty && newLeaderOpt.isDefined && newLeaderOpt.get != leader.get`
    
    We would consider it a successful election even though we should not.
    
    I also changed the result type as we never return `None` (we throw an exception instead).

----


> Leader is not set to -1 when it is shutdown if followers are down
> -----------------------------------------------------------------
>
>                 Key: KAFKA-3096
>                 URL: https://issues.apache.org/jira/browse/KAFKA-3096
>             Project: Kafka
>          Issue Type: Bug
>    Affects Versions: 0.9.0.0
>            Reporter: Ismael Juma
>            Assignee: Ismael Juma
>              Labels: reliability
>
> Assuming a cluster with 2 brokers with unclear leader election disabled:
> 1. Start brokers 0 and 1
> 2. Perform partition assignment
> 3. Broker 0 is elected leader
> 4. Produce message and wait until metadata is propagated
> 6. Shutdown follower
> 7. Produce message
> 8. Shutdown leader
> 9. Start follower
> 10. Wait for leader election
> Expected: leader is -1
> Actual: leader is 0
> We have a test for this, but a bug in `waitUntilLeaderIsElectedOrChanged` means that `newLeaderOpt` is not being checked.



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