diff --git a/ci/lib.sh b/ci/lib.sh
index 29dc740d40..c8c2c38155 100755
--- a/ci/lib.sh
+++ b/ci/lib.sh
@@ -34,6 +34,11 @@ save_good_tree () {
 # successfully before (e.g. because the branch got rebased, changing only
 # the commit messages).
 skip_good_tree () {
+	if test "$TRAVIS_DEBUG_MODE" = true
+	then
+		return
+	fi
+
 	if ! good_tree_info="$(grep "^$(git rev-parse $CI_COMMIT^{tree}) " "$good_trees_file")"
 	then
 		# Haven't seen this tree yet, or no cached good trees file yet.