Merge remote-tracking branch 'origin/release_utils' into release_utils
diff --git a/_utils.sh b/_utils.sh
index b63379a..b1d03b2 100644
--- a/_utils.sh
+++ b/_utils.sh
@@ -58,7 +58,9 @@
 }
 
 function get_pom_version {
+  set +u
   echo $(${MVN} help:evaluate -Dexpression="project.version" -q -DforceStdout)
+  set -u
 }
 
 function set_pom_version {
diff --git a/release_snapshot_branch.sh b/release_snapshot_branch.sh
index 5a4d274..202773f 100755
--- a/release_snapshot_branch.sh
+++ b/release_snapshot_branch.sh
@@ -26,7 +26,9 @@
 function create_snapshot_branch {
   cd "${SOURCE_DIR}"
 
+  set +u
   version=$(mvn help:evaluate -Dexpression="project.version" -q -DforceStdout | sed "s/-SNAPSHOT//")
+  set -u
   branch="v${version}"
 
   git checkout -b ${branch}
diff --git a/stage_jars.sh b/stage_jars.sh
index 0dd180c..925dd46 100755
--- a/stage_jars.sh
+++ b/stage_jars.sh
@@ -48,7 +48,9 @@
   set_pom_version "${version}"
 
   options="-Prelease,docs-and-source -DskipTests -DretryFailedDeploymentCount=10"
+  set +u
   ${MVN} clean deploy ${options} -Dflink.version=${FLINK_VERSION}
+  set -u
 
   cd "${RELEASE_DIR}"
   rm -rf "${clone_dir}"