We had a failure today (details below). The situation is one where someone created a branch named 'a', then subsequently created an 'a/b' branch.
We were wondering if QB could perform its fetch using the '—prune' option to prevent this type of failure going forward.
 
2016-08-04 00:00:07,553 [pool-1-thread-1351] INFO com.pmease.quickbuild.repositorysupport.Repository - Determining head revision for repository: ver_server_git
2016-08-04 00:00:14,495 [pool-1-thread-1353] ERROR com.pmease.quickbuild.execution.LineConsumer - error: 'refs/remotes/origin/ryanmarcus' exists; cannot create 'refs/remotes/origin/ryanmarcus/rollback-47595'
2016-08-04 00:00:14,495 [pool-1-thread-1353] ERROR com.pmease.quickbuild.execution.LineConsumer - error: some local refs could not be updated; try running
2016-08-04 00:00:14,495 [pool-1-thread-1353] ERROR com.pmease.quickbuild.execution.LineConsumer - 'git remote prune origin' to remove any old, conflicting branches
2016-08-04 00:00:14,498 [pool-1-thread-1353] ERROR com.pmease.quickbuild.execution.LineConsumer - error: Could not fetch origin
2016-08-04 00:00:14,578 [pool-1-thread-1224] ERROR com.pmease.quickbuild.DefaultBuildEngine - Error processing build request.
    java.lang.RuntimeException: Error executing check condition job.
        at com.pmease.quickbuild.CheckConditionTask.reduce(CheckConditionTask.java:39)
        at com.pmease.quickbuild.CheckConditionTask.reduce(CheckConditionTask.java:16)
        at com.pmease.quickbuild.grid.GridTaskFuture.get(GridTaskFuture.java:102)
        at com.pmease.quickbuild.grid.GridTaskFuture.get(GridTaskFuture.java:106)
        at com.pmease.quickbuild.DefaultBuildEngine.process(DefaultBuildEngine.java:332)
        at com.pmease.quickbuild.DefaultBuildEngine.access$000(DefaultBuildEngine.java:139)
        at com.pmease.quickbuild.DefaultBuildEngine$2.run(DefaultBuildEngine.java:1136)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
    Caused by: com.pmease.quickbuild.QuickbuildException: Failed to run command: git fetch --all -q
    Command return code: 1
    Command error output: error: 'refs/remotes/origin/ryanmarcus' exists; cannot create 'refs/remotes/origin/ryanmarcus/rollback-47595'
    error: some local refs could not be updated; try running
     'git remote prune origin' to remove any old, conflicting branches
    error: Could not fetch origin