pub fn current_branch() -> Option<&'static str>Expand description
The branch HEAD names, or None on a detached head — asked of git ONCE
per process and lent to every check that wants it.
Two always-on pre-commit checks (branch-pattern, branch-protect) open
with this same question. Asked twice it is two spawns on every commit,
which is exactly the o(checks) growth tests/spawn_budget.rs exists to
refuse; asked once it is the price of one check, however many share it.