pub fn match_path(
        &self,
        path: impl AsRef<Utf8Path>,
        match_cb: impl FnMut(&'g PackageId),
    ) -> PathMatch {
        process_path(
            path.as_ref(),
            &self.new.workspace(),
            &self.rules.path_rules,
            match_cb,
        )
    }
Returns what *would* happen if a given path was added to the changed set.

This does not add any path to the changed set, but indicates what *would* happen if a path
is added.

This method may be used to ensure that all paths in a repository are covered by at least one
rule if they don't match a package.

`match_cb` is called for all package IDs that the path matches.
tools/determinator/src/determinator.rs