Function posix_join 

pub fn posix_join(uri: &str, location: &str) -> String

posixpath.join(uri, location) semantics: an absolute location (leading /) replaces uri outright; otherwise location is appended, with a / inserted only if uri is non-empty and doesn’t already end in one. (sphinx/util/inventory.py:79,157 — location = posixpath.join(uri, location).)