SQL copilots: SQL and Warehouse Copilots

# ✅ Author → validate → explain → optional run
FORBIDDEN = {"drop", "delete", "update", "insert", "alter", "grant"}

def run_copilot_sql(sql: str, *, user: str, dry_run: bool = True):
    ast = parse_sql(sql)
    if any(n in FORBIDDEN for n in ast.verbs):
        raise PermissionError("mutating SQL blocked")
    if not tables_allowlisted(ast.tables, user):
        raise PermissionError("table not allowlisted")
    plan = explain(sql)
    if plan.bytes_scanned > 50_000_000_000:  # 50GB
        raise PermissionError("scan too large")
    if dry_run:
        return {"plan": plan, "rows": None}
    return {"plan": plan, "rows": execute_readonly(sql, timeout_s=30)}