Function path_from_usage

atomic-cli/src/agent_error.rs:65–89

The command path clap itself scoped the error to, read out of its usage line. This is the authoritative source when it exists. argv alone cannot answer the question: in `atomic --json memory new`, clap rejects `--json` at the ROOT and never reaches `memory`, yet `memory` and `new` are both real subcommands sitting later in argv. Walking argv names `memory new` — a command that never ran — and the

(root: &clap::Command, usage: &str)

/// <COMMAND>`; the path is its leading run of bare lowercase tokens after the
/// binary name.
fn path_from_usage(root: &clap::Command, usage: &str) -> Option<String> {
    let mut toks = usage.split_whitespace();
    if toks.next()? != root.get_name() {
        return None;
    }
    let mut node = root;
    let mut parts: Vec<String> = Vec::new();
    for tok in toks {
        if !tok
            .chars()
            .all(|c| c.is_ascii_lowercase() || c == '-' || c.is_ascii_digit())
            || tok.starts_with('-')
        {
            break;
        }
        match node.find_subcommand(tok) {
            Some(child) => {
                parts.push(child.get_name().to_string());
                node = child;
            }
            None => break,
        }
    }
    Some(parts.join(" "))
}

/// Walk argv against the live command tree to the deepest node that actually
/// exists.