diff --git a/etc/ci/taskcluster/decisionlib.py b/etc/ci/taskcluster/decisionlib.py
index 83d76c1d022..c10bdf6ccaf 100644
--- a/etc/ci/taskcluster/decisionlib.py
+++ b/etc/ci/taskcluster/decisionlib.py
@@ -226,4 +226,4 @@ def expand_dockerfile(dockerfile):
 
 
 def deindent(string):
-    return re.sub("\n +", " \n ", string)
+    return re.sub("\n +", " \n ", string).strip()