Function decode_configmap_sql 

pub fn decode_configmap_sql(
    configmap: &ConfigMap,
    key: &str,
    gzip: bool,
) -> Result<String>

Read the SQL out of the ConfigMap a plan’s sqlRef names.

Compressed SQL lives in binaryData; the legacy uncompressed shape lives in data. A missing key is an error rather than an empty plan: an empty string here would read as “this change does nothing”.