Build failed in Jenkins: calligra_master » All,LINBUILDER #990

[KDE CI System]

See <http://build.kde.org/job/calligra_master/Variation=All,label=LINBUILDER/990/>

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Started by upstream project "calligra_master" build number 990
originally caused by:
 Started by remote host 2a01:4f8:160:9363::9 with note: Triggered by commit
Building remotely on LinuxSlave - 4 (PACKAGER LINBUILDER) in workspace <http://build.kde.org/job/calligra_master/Variation=All,label=LINBUILDER/ws/>
Running Prebuild steps
[LINBUILDER] $ /bin/sh -xe /tmp/hudson5884104808665073731.sh
+ /home/jenkins/scripts/setup-env.sh

Preparing to perform KDE Continuous Integration build
== Setting Up Sources

Branch jenkins set up to track remote branch master from origin.

== Cleaning Source Tree

HEAD is now at 1952754 Remove unneeded includes in libs/flake
Success build forhudson.tasks.Shell at 25416211
 > git rev-parse --is-inside-work-tree # timeout=10
Fetching changes from the remote Git repository
 > git config remote.origin.url git://anongit.kde.org/calligra.git # timeout=10
Fetching upstream changes from git://anongit.kde.org/calligra.git
 > git --version # timeout=10
 > git fetch --tags --progress git://anongit.kde.org/calligra.git +refs/heads/*:refs/remotes/origin/*
Checking out Revision ac461507940d33536b1f5da1349f38c515b82bd0 (refs/heads/jenkins)
 > git config core.sparsecheckout # timeout=10
 > git checkout -f ac461507940d33536b1f5da1349f38c515b82bd0
FATAL: Could not checkout null with start point ac461507940d33536b1f5da1349f38c515b82bd0
hudson.plugins.git.GitException: Could not checkout null with start point ac461507940d33536b1f5da1349f38c515b82bd0
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl$8.execute(CliGitAPIImpl.java:1621)
	at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler$1.call(RemoteGitImpl.java:153)
	at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler$1.call(RemoteGitImpl.java:146)
	at hudson.remoting.UserRequest.perform(UserRequest.java:118)
	at hudson.remoting.UserRequest.perform(UserRequest.java:48)
	at hudson.remoting.Request$2.run(Request.java:328)
	at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)
Caused by: hudson.plugins.git.GitException: Command "git checkout -f ac461507940d33536b1f5da1349f38c515b82bd0" returned status code 128:
stdout: 
stderr: fatal: reference is not a tree: ac461507940d33536b1f5da1349f38c515b82bd0

	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandIn(CliGitAPIImpl.java:1437)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.access$500(CliGitAPIImpl.java:87)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl$8.execute(CliGitAPIImpl.java:1616)
	... 10 more