pub fn component_problem(name: &str) -> Option<&'static str>Expand description
Why name is not a safe single path component, or None when it is.
Used before any path is built from a declared name (target.gateway,
target.mode, tag providers, type halves), so a hostile value cannot
walk out of its directory (T-21-12). Refuses: empty, ., .., any /,
\ or NUL, and any dot-leading name.