+if [ -z "$branches" ]; then
+ # this check is only needed when no branches have been passed
+ name="$(git symbolic-ref HEAD | sed 's#^refs/heads/##')"
+ base_rev="$(git rev-parse --short --verify "refs/top-bases/$name" 2>/dev/null)" ||
+ die "not on a TopGit-controlled branch"
+ branches="$name"
+else
+ name="${branches##*,}" # the last of the comma-separated items
+fi
+# $name holds the current branch
+# $branches holds the comma-separated list of branches
+# $name is equal to the last of the list of branches
+
+
+playground="$(mktemp -d -t tg-export.XXXXXX)"