use std::io;use toml::Value as TomlValue;const DEFAULT_PROJECT_ROOT_MARKERS: &[&str] = &[".git"];/// Reads `project_root_markers` from a merged `config.toml` [toml::Value].////// Invariants:/// - If `project_root_markers` is not specified, returns `Ok(None)`./// - If `project_root_markers` is specified, returns `Ok(Some(markers))` where///   `markers` is a `Vec<String>` (including `Ok(Some(Vec::new()))` for an///   empty array, which indicates that root detection should be disabled)./// - Returns an error if `project_root_markers` is specified but is not an///   array of strings.pub fn project_root_markers_from_config(config: &TomlValue) -> io::Result<Option<Vec<String>>> {    let Some(table) = config.as_table() else {        return Ok(None);    };    let Some(markers_value) = table.get("project_root_markers") else {        return Ok(None);    };    let TomlValue::Array(entries) = markers_value else {        return Err(io::Error::new(            io::ErrorKind::InvalidData,            "project_root_markers must be an array of strings",        ));    };    if entries.is_empty() {        return Ok(Some(Vec::new()));    }    let mut markers = Vec::new();    for entry in entries {        let Some(marker) = entry.as_str() else {            return Err(io::Error::new(                io::ErrorKind::InvalidData,                "project_root_markers must be an array of strings",            ));        };        markers.push(marker.to_string());    }    Ok(Some(markers))}pub fn default_project_root_markers() -> Vec<String> {    DEFAULT_PROJECT_ROOT_MARKERS        .iter()        .map(ToString::to_string)        .collect()}