--- a/contrib/merge-test-compat.sh	Tue Jan 21 23:48:41 2020 +0700
+++ b/contrib/merge-test-compat.sh	Mon Jan 20 22:43:11 2020 +0700
@@ -2,14 +2,12 @@
 set -euox pipefail
 
 unset GREP_OPTIONS
-NOTOPIC="--config experimental.topic-mode=ignore"
 
-compatbranches=`hg branches --quiet | grep 'mercurial-' | grep -v ':' | sort -n --reverse`
+compatbranches=$(hg branches --quiet | grep 'mercurial-' | grep -v ':' | sort -n --reverse)
 prev='stable'
 for branch in $compatbranches; do
-    hg up $branch
-    hg merge $prev
+    hg up "$branch"
+    hg merge "$prev"
     hg commit -m "test-compat: merge $prev into $branch"
     prev=$branch
 done
-