Running as SYSTEM
Building on master in workspace /var/lib/jenkins/jobs/NFD/workspace
The recommended git tool is: NONE
No credentials specified
 > git rev-parse --is-inside-work-tree # timeout=10
Fetching changes from the remote Git repository
 > git config remote.origin.url https://gerrit.named-data.net/NFD # timeout=10
Pruning obsolete local branches
Fetching upstream changes from https://gerrit.named-data.net/NFD
 > git --version # timeout=10
 > git --version # 'git version 2.17.1'
 > git fetch --tags --progress --prune -- https://gerrit.named-data.net/NFD refs/heads/master # timeout=10
 > git rev-parse FETCH_HEAD^{commit} # timeout=10
JENKINS-19022: warning: possible memory leak due to Git plugin usage; see: https://wiki.jenkins.io/display/JENKINS/Remove+Git+Plugin+BuildsByBranch+BuildData
Checking out Revision 3dc9fd0b826b80d2e2bd40901875748e2ceaa5d3 ()
 > git config core.sparsecheckout # timeout=10
 > git checkout -f 3dc9fd0b826b80d2e2bd40901875748e2ceaa5d3 # timeout=10
Commit message: "Prepare release 0.7.1"
FATAL: null
java.lang.NullPointerException
	at java.base/java.util.TreeMap.compare(TreeMap.java:1291)
	at java.base/java.util.TreeMap.put(TreeMap.java:536)
	at hudson.util.CopyOnWriteMap.put(CopyOnWriteMap.java:104)
	at hudson.plugins.git.GitTagAction.<init>(GitTagAction.java:47)
	at hudson.plugins.git.GitSCM.checkout(GitSCM.java:1369)
	at hudson.scm.SCM.checkout(SCM.java:505)
	at hudson.model.AbstractProject.checkout(AbstractProject.java:1206)
	at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:637)
	at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:86)
	at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:509)
	at hudson.model.Run.execute(Run.java:1907)
	at hudson.matrix.MatrixBuild.run(MatrixBuild.java:323)
	at hudson.model.ResourceController.execute(ResourceController.java:97)
	at hudson.model.Executor.run(Executor.java:429)
Started calculate disk usage of build
Finished Calculation of disk usage of build in 0 seconds
Started calculate disk usage of workspace
Finished Calculation of disk usage of workspace in 0 seconds
Finished: FAILURE