die "invalid branch name: $name"
baserev="$(git rev-parse --verify "refs/top-bases/$name" 2>/dev/null)" ||
die "not a TopGit topic branch: $name"
die "invalid branch name: $name"
baserev="$(git rev-parse --verify "refs/top-bases/$name" 2>/dev/null)" ||
die "not a TopGit topic branch: $name"