software/slaprunner: Fail on undefined variable expansion.

software/slaprunner/buildout.hash.cfg

@@ -31,7 +31,7 @@ md5sum = 9db9957f452bda370cb2d5cc2e833e85
 
 [template-runner-export-script]
 filename = template/runner-export.sh.jinja2
-md5sum = bbe59ef9544322d34d45d34b875dbc4e
+md5sum = 7ba7ede9bf850551a9add58812e95d6e
 
 [instance-runner-export]
 filename = instance-runner-export.cfg.in

software/slaprunner/template/runner-export.sh.jinja2

@@ -4,7 +4,8 @@ export LC_ALL
 umask 077
 
 # Exit on any error, to prevent inconsistent backup
-set -e
+# Error on unset variable expansion
+set -eu
 
 # Redirect output to log
 exec > >(tee -ai '{{ output_log_file }}')