Function save_json 

pub(crate) fn save_json(
    root: &Path,
    cargo_args: &[&str],
    dest: &Path,
) -> Result<()>

Runs cargo clippy --message-format=json and writes every output line to dest, creating or truncating the file.

Does not apply -D warnings — the exit status of clippy is ignored so that artifact collection always succeeds even when warnings are present.

Errors

Returns an error if the process cannot be spawned or the file cannot be written.