pub type PreRunHook = fn(App) -> PreRunFuture;Expand description
A pre-run hook, invoked with the App before command dispatch.
Runs after CLI parsing and before the matched command. Leaf crates
register cross-cutting pre-dispatch logic here (e.g. the self-update
policy check) via distributed_slice, keeping rtb-cli decoupled
from them — exactly like BUILTIN_COMMANDS.
Contract: a hook must be fast and order-independent — link-time
registration order across crates is not deterministic. A hook returning
Err aborts the run before the command executes, so advisory hooks that
must not block the command should swallow their own errors.