Function parents

atomic-cli/src/commands/push/helpers.rs:530–542

Parent lookup backed by a map, for pure chain tests.

(
        pairs: &[(&str, Option<&str>)],
    )

    /// Parent lookup backed by a map, for pure chain tests.
    fn parents(
        pairs: &[(&str, Option<&str>)],
    ) -> impl FnMut(&str) -> Result<Option<String>, String> {
        let map: HashMap<String, Option<String>> = pairs
            .iter()
            .map(|(k, v)| (k.to_string(), v.map(str::to_string)))
            .collect();
        move |name: &str| {
            map.get(name)
                .cloned()
                .ok_or_else(|| format!("view '{}' not found", name))
        }
    }

    // Chain Construction Tests